JPH05292038A - Submarine high-speed optical transmission system - Google Patents

Abstract

PURPOSE:To perform high-speed transmission and to perform the monitoring and control of a fault, etc., by remote operation by outputting monitor signal light with the same wavelength as that of excitation light, and multiplexing by synthesizing the main signal light with the monitoring signal light. CONSTITUTION:The transmission of a monitor signal from submarine optical terminal station transmission equipment 24 is performed by using a light source 114 for monitor signal of 1480nm wavelength band provided in a light booster amplifier 40. Thereby, the monitoring signal light can be transmitted to a downstream line by wavelength-superimposing the monitoring signal light on the main signal light. In such a case, a WDM coupler 100 for wavelength multiplex for the monitoring signal light and the main signal light is also used as a WDM coupler for excitation light to prevent the output of the light booster amplifier 40 from being decreased. Also, two Er doped fibers are used as a submarine optical amplification repeater 2. A light source for excitation of 1480nm wavelength band is used in each a Er doped fiber, and an initial stage is employed for forward excitation, and a rear stage for backward excitation. Thereby, it is possible to provide a low NF and high output simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission system applied to a relay transmission network system, and in particular,
The present invention relates to a high-speed optical transmission system in which an optical fiber cable is laid on the seabed.

[0002]

2. Description of the Related Art In recent years, the use of an optical transmission system has been studied to construct a long-distance transmission system.

Conventionally, as an optical communication system, for example,
There is JP-A-3-296334. This is to locate a failure point in an optical system quickly and accurately by arranging a single or a plurality of optical loopback components in an optical line.

[0004]

In the case of long-distance transmission, it is important in maintenance to remotely monitor and control the system such as finding a failure point. In particular,
It is necessary that the repeater installed on the seabed can be operated remotely. However, this conventional technique only discloses a technique for performing loopback, and does not consider remote operation or the like. Therefore, conventionally, no system having excellent maintainability has been proposed for optical transmission over a long distance at high speed.

The present invention has been made to solve such a situation, and an object thereof is to lay an optical fiber cable on the seabed to enable high-speed transmission and to monitor and control failures and the like. It is to provide a submarine high-speed optical transmission system that can be performed remotely.

[0006]

According to the first aspect of the present invention to achieve the above object, optical terminal stations are connected by an optical fiber cable laid on the seabed, and communication is performed by optical transmission. In the undersea high-speed optical transmission system for performing the optical terminal device, the optical terminal device has a transmitter for multiplexing and outputting the main signal light and the supervisory signal light, and the transmitter is an optical amplifier for optically amplifying the main signal light. The booster amplifier has a booster amplifier, and this optical booster amplifier optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light, and outputs a supervisory signal light having the same wavelength as the pumping light to There is provided a submarine high-speed optical transmission system having a function of multiplexing and outputting signal light and supervisory signal light.

At least one repeater can be provided between the optical terminal devices. The repeater may include a transmitter that multiplexes and outputs the main signal light and the supervisory signal light, and the transmitter may include an optical booster amplifier that optically amplifies the main signal light.

The optical booster amplifier optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light, and outputs a supervisory signal light having the same wavelength as the pumping light to generate the main signal light. It may have a function of multiplexing and outputting the monitoring signal light.

The optical booster amplifier is an optical fiber amplifier that optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light, and a monitoring light source that outputs monitoring signal light having the same wavelength as the pumping light. And a coupler that multiplexes the main signal light and the supervisory signal light.

Further, the repeater apparatus uses a pumping light having a wavelength different from that of the main signal light to optically amplify the main signal light received from the preceding apparatus, and a first amplifying section for amplifying the main signal light. A second amplification unit that further optically amplifies the signal light by using pumping light having a wavelength different from that of the main signal light, and the second amplification unit mainly uses pumping light having a wavelength different from that of the main signal light. It is possible to have a function of optically amplifying the signal light, outputting the supervisory signal light having the same wavelength as the pumping light, and multiplexing and outputting the main signal light and the supervisory signal light.

According to the second aspect of the present invention, an optical terminal station is provided in a submarine high-speed optical transmission system in which optical terminal cables are connected to each other by an optical fiber cable laid on the seabed to perform communication by optical transmission. At least one repeater is arranged between the devices, and the repeater optically amplifies the main signal light received from the preceding device by using pumping light having a wavelength different from that of the main signal light. Submarine high-speed optical transmission system, characterized in that it includes a second amplification unit that further amplifies the amplified main signal light using pumping light having a wavelength different from that of the main signal light. Will be provided.

A loop having a first amplification section and a second amplification section for each of the downlink and the uplink, and connecting the downlink and uplink the first amplification section and the second amplification section. A configuration further comprising a back unit, wherein the loopback unit has an optical switch, and the optical switch can switch between normal transmission and one-way loopback from upstream to downstream and downstream from upstream. can do.

Further, at least one of the first amplification section and the second amplification section is provided with at least two pump light generation light sources, a working light source and a spare light source, and two pump light generation sources are used by switching. It can be in this case,
Having means for separating the supervisory signal sent from the pre-stage device,
The excitation light generation source can be switched according to the instruction of the monitoring signal.

A wavelength division multiplexing (WDM) coupler is used as a means for wavelength division or separation of the main signal light and the supervisory signal light. This WDM coupler can be shared as a wavelength multiplexing coupler for main signal light and pumping light.

Further, it is possible to have a means for separating the supervisory signal light sent from the preceding stage device, and to switch the loopback optical switch according to the instruction of the supervisory signal.

According to the third aspect of the present invention, an optical terminal station in an undersea high-speed optical transmission system in which optical terminal cables are connected to each other by optical fiber cables laid on the seabed to perform communication by optical transmission. At least one repeater is arranged between the devices, and the repeater optically amplifies the main signal light received from the preceding device by using pumping light having a wavelength different from that of the main signal light. Section, means for separating the supervisory signal sent from the pre-stage device, and means for changing the output of the pumping light of the optical amplifier section and the output level of the main signal light according to the instruction of the supervisory signal. A submarine high-speed optical transmission system is provided.

Further, according to the present invention, between the optical terminal devices,
A submarine high-speed optical transmission system for performing communication by optical transmission by connecting with an optical fiber cable laid on the seabed, which is a relay device arranged on the seabed between optical terminal devices and which is an optical amplification unit for performing optical amplification. And a control unit therefor, and a plurality of circuit units, and a pressure resistant casing having a cylindrical housing portion for housing the plurality of circuit units, and the pressure resistant casing has three sets of circuits. A relay device is provided in which a unit is arranged on an inner circumference of a pressure-resistant housing along each side of a triangle.

The optical amplification section can be configured to have one system for upstream and one for downstream. Each optical amplification section can be configured to have first and second amplification sections each having an optical amplification fiber. The optical amplification fibers of the respective amplification units may be wound on a common bobbin.

[0019]

In the optical terminal device, the transmitting section includes the main signal light,
The monitor signal light is multiplexed and output. At this time, in the transmitter, the main signal light is optically amplified by the optical booster amplifier. That is, this optical booster amplifier optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light. Further, the optical booster amplifier outputs the supervisory signal light having the same wavelength as the pumping light, and multiplexes the main signal light and the supervisory signal light and outputs the multiplexed signal.

As described above, according to the present invention, a high-output signal light can be transmitted by optically amplifying with pumping light. Therefore, it is possible to realize high-speed transmission over a long distance such as the seabed.

Further, by providing the relay device, it is possible to perform optical transmission on the ocean floor over a longer distance.

Further, since the supervisory signal light is multiplexed with the main signal and sent to the post-stage device, the repeater device receives the supervisory signal according to the supervisory signal.
It is possible to monitor and control remotely. In this case, light having the same wavelength as the excitation light for optical amplification is used as the monitoring signal. As a result, it is possible to share the wavelength multiplexing coupler for separating and multiplexing the signal lights with the pumping light and the monitoring light. This is preferable because the amount of material can be reduced correspondingly and the loss due to the coupler can be reduced, so that it is particularly preferable for a relay device installed on a long-distance seabed.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

The embodiment of the present invention described below is an optical transmission system applied to a relay transmission network system, and in particular, is an example of an optical transmission system for laying an optical cable on the seabed to transmit information. .. FIG. 1 shows the overall configuration of the relay transmission network.

In the relay transmission network shown in FIG. 1, the optical transmission system of this embodiment is mainly applied to long distance transmission between large nodes. Generally, in a backbone transmission system between large nodes having a ladder structure, a plurality of transmission lines are provided to ensure reliability. A part of such a transmission line may include a submarine transmission line. For example, in a Japanese longitudinal transmission line, one or two longitudinal transmission lines include a submarine transmission line portion centering on a portion that crosses a strait such as Hokkaido / Honshu.

In this relay transmission network, the large nodes ND to which a plurality of small nodes nd are connected are connected by the optical transmission systems OTC and OTD for land and the optical transmission systems OTA and OTB for the submarine A type.

A type optical transmission system OTA (hereinafter, simply referred to as A
Type system) is an optical amplifier repeater (1R-REP;
It is an ultra-long-distance undersea relay system that uses 2) (1R-REP may be abbreviated below). This type A system controls the output light source wavelength in the optical terminal equipment (details will be described later) accommodated in the node to 1.552 μm ± 0.001 μm in order to achieve a maximum transmission distance of 1000 km and a 1R-REP2 interval of 100 km. The transmission level is 2488.32 Mb / s (STM-16) and the output level is +6.
~ + 8dBm, minimum received light level is -25dBm or less, transmission speed 9953.
At 28 Mb / s (equivalent to STM-64), the output level is set to +4 to +8 dBm, and the minimum received light level is set to -27 dBm or less. The transmission path code uses scrambled binary NRZ (non-conversion).

The 1R-REP 2 can be configured to be shared by two kinds of transmission speeds by changing the output level by remote control. The configuration of 1R-REP2 will be described later.

The internal interface of the terminal device is STM-1
It holds x64 series or STM-4x16 series. The STM-1 × 4 series and the STM-4 × 1 series can be exchanged with each other.

The type B system is a long-distance (300 km) sea-bottom repeaterless system, and has an optical loss of 0.18 dB / km (1.55 μm), for example.
Optical output level +1 using cut-off shift optical fiber
Realizes 300km non-relay with 9dBm and minimum reception level of -38dBm. As a countermeasure for stimulated Brillouin scattering (SBS) due to high output, a spread spectrum method is used.

In this embodiment, a compact and high-performance system is constructed by using the integrated light source technology, the ultra-high-speed circuit IC technology, the highly integrated CMOS LSI technology, and the high-density mounting technology. be able to.

The optical transmission system OTC for land is 100 k
1R-REP is inserted every m, and further 320km,
An optical regenerator (3R-REP, sometimes abbreviated as 3R-REP hereinafter) 4 is inserted.

FIG. 2 shows an example of the configuration of the large node ND used in the above network, which is connected to the undersea optical transmission system.

The large node ND connected to the submarine optical transmission system is installed on land and is connected to optical fiber cables (also referred to simply as optical fiber in this specification) 6 and 8 laid on the seabed. The large node ND is an A-type submarine optical terminal device (terminal or LT) that constitutes the A-type system.
-MUX 10) and a B-type submarine optical terminal device (terminal or LT-MUX) that constitutes a B-type system.
12 and a land optical terminal device (land L
T-MUX) 14, a terminal relay device 16, a path connect device / multiplex conversion device 18, an ATM transmission device 20,
It has a VC-3 / 4 cross connect 22 for connecting these. The A-type submarine optical terminal device 10 and the B-type submarine optical terminal device 12 are respectively provided in a multiplexed manner, and are 10G multiplexed terminal stations (or 10G terminal stations) or 2.4G multiplexed terminal stations ( Or 2.4G terminal).
The A-type submarine optical terminal device 10 has a transmission rate of 10 Gb / s or 2.4 Gb / s, and the latter has a transmission rate of 2.4 Gb / s.
Each transmission can be performed at the transmission speed of. In the present specification, one having a transmission rate of 10 Gb / s is, for example, 1
A system having a transmission rate of 2.4 Gb / s and a system having a transmission rate of 2.4 Gb / s may be referred to as a 2.4 Gb / s system, for example.

With such a structure, a high-reliability network is achieved by a ladder structure between the large nodes and route distribution and switching of VC-3 / 4 paths. Therefore, the SDH V
A VC-3 / 4 cross-connect 22 is installed to perform C-3 / 4 level path switching and path setting. Submarine optical terminal device 1
0 and 12 are generally connected to this cross connect 22 by an intra-station transmission line. Since the transmission line switching is performed by bypassing the path level by the VC-3 / 4 cross connect 22, it is not necessary to use the section-level redundant configuration of the transmission line itself.

Next, the outline of the configuration of the optical transmission system constituting the present embodiment will be described with reference to the drawings.

3 and 4 show the outline of the configuration of the A type 10 Gb / s system. In this embodiment, six systems 1 to 6 are provided. In these figures, one system out of the multiplexed systems is shown.

As shown in these figures, A type 10 Gb /
s system is a 10G multiplexed terminal station (LT-MUX) having a submarine terminal station transmitter 24 and a submarine terminal station receiver 26.
10 and multiple submarine linear repeaters (1R-R
EP (optical amplification repeater) 2 and a dispersion shift optical fiber 6 for connecting them. Details of each component will be described later. Here, only the outline will be described.

The submarine terminal station transmitter 24 and the submarine terminal station receiver 26 include a plurality of intra-station interfaces 28, a multiplexing / demultiplexing and section processing section 30 for performing multiplexing and demultiplexing, and an electrical signal for converting an electrical signal into an optical signal. / Optical converter 3
2 and an optical / electrical conversion unit 34 for converting an optical signal into an electric signal
An optical booster amplifier 40 having an optical fiber amplifier 41 for amplifying a transmitted optical signal, an optical preamplifier 42 having an optical fiber amplifier 43 for amplifying a received optical signal, a supervisory controller 36 for supervisory control, and a timing signal. And a timing supply device 38 for supplying. The multiplexing / demultiplexing and section processing unit 30 includes a multiplexing circuit 44 and a demultiplexing circuit 46. The timing supply device 38 has a clock generation circuit 48 and a timing extraction circuit 50.

FIG. 5 shows an outline of the configuration of the optical amplification repeater (1R-REP) 2. In FIG. 5, the optical amplification repeater (1R-R
The EP) 2 has an optical amplifier (optical fiber amplifier) 52, a supervisory control circuit (supervisory control signal processing circuit) 54, a power supply section and a surge protection section 56. The optical amplifier (optical fiber amplifier) 52 has a downlink and an upstream.

Next, an outline of the configuration and operation of the type A system will be described along the flow of signals.

The submarine terminal station transmitter 24 uses, as a transmission light source, a modulator integrated light source module 82 having a wavelength of 1552 nm and small chirping. Further, a pumping light source (pumping laser diode) having a wavelength of 1480 nm is used for the optical fiber amplifier 41, and the optical amplification is performed by the backward pumping method. Then, the total transmission distance of 1000 km is realized by optimizing the transmission power and the chirping amount.

The transmission of the supervisory signal from the submarine terminal station transmitter 24 is performed at a wavelength of 1480n provided in the optical booster amplifier 40.
The m-band supervisory signal light source 114 is used. This allows
The supervisory signal light is wavelength-multiplexed with the main signal light and transmitted downstream.
Here, in order to prevent the output of the optical booster amplifier 40 from decreasing,
WDM coupler 10 for wavelength multiplexing of supervisory signal light and main signal light
0 also serves as a WDM coupler for pumping light.

The optical amplification repeater 2 uses two Er-doped fibers. A light source for pumping the wavelength 1480 nm band
One is used for each Er-doped fiber, and forward pumping is used for the first stage and backward pumping is used for the second stage. Thereby, low NF and high output can be realized at the same time. In order to ensure the reliability of the submarine optical amplifier repeater, the pump light source is PB
It is duplexed by the polarization multiplexing method using S.

In the reception of the supervisory signal light in the submarine optical amplifier repeater, the supervisory signal light is demultiplexed by using the WDM coupler for pumping Er-doped fiber at the first stage and received by the dedicated receiver. This makes it possible to minimize the deterioration of NF (0.2 dB or less) and receive the supervisory signal.

The transmission of the supervisory signal light in the optical amplification repeater is
A monitoring signal light source having a wavelength of 1480 nm band is used. The supervisory signal light is wavelength-multiplexed with the main signal light and transmitted downstream. In order to prevent the output from decreasing in the combination of the supervisory signal light and the main signal light,
It also serves as a WDM coupler for pumping Er-doped fiber in the latter stage.

By such a supervisory signal transmission / reception system, the remote control of the output of the submarine optical amplification repeater from the terminal station, the remote control at the time of loopback, the transfer of the monitor signal of the operating state of the submarine optical amplification repeater from upstream to downstream. It will be possible to evaluate the failure of optical cables and submarine optical amplifier repeaters.

In the present invention, in order to monitor whether the optical transmission is normally performed, the main signal light is looped back as described later. This submarine optical amplification repeater 2 takes out the main signal light for loopback from the E at the first stage and the latter stage.
This is achieved by installing a 3 dB optical coupler at the midpoint of the r-doped fiber. With this method, a loopback system can be realized without deterioration of NF and reduction of output. In this case, a loopback is realized by remotely controlling the two optical switches in the submarine optical amplification repeater 2 by a control signal from the terminal station 10 using a supervisory signal system.

In the submarine terminal receiving device 26, 1480 nm
Highly sensitive reception is achieved by a forward pumping light preamplifier using a (or 980 nm) band pumping light source.

When the supervisory signal is received by the submarine terminal station receiver 26, the supervisory signal is demultiplexed using the Er-doped fiber pumping WDM coupler 120 and received by the dedicated receiver 130. As a result, it is possible to minimize the deterioration of NF (0.2 dB or less) and receive the supervisory signal.

Next, the overall configuration of the seabed A type 2.4 Gbit / s system and its features will be described with reference to FIGS. 6 and 7, focusing mainly on the differences from the 10 Gbit / s system.

As shown in these figures, A type 2.4 Gb
/ S system is a 2.4G multiplexed terminal station (LT-MU) having a submarine terminal station transmitter 24 and a submarine terminal station receiver 26.
X) 10a, a plurality of optical amplification repeaters 2 installed on the seabed, and a dispersion shift optical fiber 6 connecting them. This A type 2.4 Gb / s system
It has the same configuration as the A-type 10 Gb / s system except that the transmission speed is low and that it does not have an optical preamplifier.

The A type 2.4 Gb / s system can be commonly constructed by using the configuration of the A type 10 Gb / s system. Therefore, by partially changing the function of the A type 10 Gb / s system, this A type 2.4 G
It can be configured to realize a b / s system.

An MQW (multiple quantum well) -DFB (distributed feedback type) laser having a wavelength of 1552 nm is used as a transmission light source of the submarine optical terminal transmitter 24 of the A type 2.4 Gb / s system.

As the submarine terminal station receiver 26, a small low power consumption type optical receiver using an APD (avalanche photodiode) is used.

In addition to the above, this system is a seabed A type 1
It has the same features as the items listed as the features of the 0 Gbit / s system.

Submarine optical amplification repeater 1 of 2.4G system
0 has the same configuration as that of the seabed type A 10 Gbit / s system shown in FIG. Therefore, the submarine A system
Taking advantage of the bit rate flexibility of the optical amplifier 52, by replacing the transmitter and receiver and remotely setting the output level of each submarine optical amplification repeater 2 using the supervisory signal system,
With the submarine optical amplifier repeater 2 and the optical cable 6 installed on the seabed, 2.4 Gb will be used in response to future traffic increase.
It is possible to upgrade from it / s to 10 Gbit / s.

Next, in FIGS. 8 and 9, the seabed B type 2.4 is shown.
1 shows the overall configuration of a Gbit / s system.

The submarine B type 2.4 Gbit / s system is
It is configured by including a 10G multiplexing terminal station (LT-MUX) 12 having a submarine terminal station transmitter 58 and a submarine terminal station receiver 60, and a normal dispersion optical fiber 8 connecting them. Details of each component will be described later.
Here, only the outline will be described.

The submarine terminal station transmitter 58 and the submarine terminal station receiver 60 include a plurality of intra-station interfaces 62, a multiplexing / demultiplexing and section processing section 64 for performing multiplexing and demultiplexing, and an electrical signal for converting an electrical signal into an optical signal. / Optical converter 6
6 and an optical / electrical converter 68 for converting an optical signal into an electric signal
An optical booster amplifier (optical booster amplifier) 74 that amplifies the transmitted optical signal, an optical preamplifier 76 that amplifies the received optical signal, a supervisory control device 70 that performs supervisory control, and a timing supply device 72 that supplies a timing signal. Have.

A low-chirping modulator integrated light source with a wavelength of 1552 nm is used as the transmission light source of the seabed B type 2.4 Gbit / s system. It is preferable that the transmission light source is temperature-stabilized at 0.01 ° C. to stabilize the wavelength. Also, in order to suppress the SBS generation from the optical fiber at the time of high output, the FM generated by the small signal from the low frequency oscillator 78
A spread spectrum method using modulation is used.

The optical booster 74 uses four pumping light sources with a wavelength of 1480 nm, is a bidirectional pumping system using polarization multiplexing technology, and employs Er-doped fiber with high conversion efficiency (80% or more). Achieves high output.

Further, by optimizing the transmission power and the amount of chirping, the total transmission distance is 300 k in the normal dispersion optical fiber 8.
realize m.

The receiving terminal station 60 realizes a high-sensitivity receiver by adopting a forward pumping light preamplifier 76 using a 1480 nm (or 980 nm) band pumping light source and a narrow band optical filter (1 nm).

By the way, when a high optical power such as +8 dBm is input as the fiber input optical power from the transmitter, stimulated Brillouin scattering (SBS) occurs,
Transmission characteristics deteriorate. As a measure against this SBS, there is a spread spectrum method. That is, as shown in FIG. 9, a sine wave from the low-frequency oscillator 78 is converted into a current signal, which is applied to the laser section of the modulator integrated light source to modulate the frequency of the laser oscillation light and equivalent. The light spectrum is diffused to suppress the generation of SBS.

Regarding the spread spectrum method, see A. Hi
rose, Y. Takashima, T .; Okoshi
By “Journal of Optical Communications vol. 12 N
o.3PP.82-85 (1991): Suppression of Stimulated Brillo
uin Scattering and Brillouin Crosstalk by Frequenc
y Sweeping Spread-Spectrum Scheme ”.

Next, the structure of the terminal station used in the present invention will be described. FIG. 10 shows an example of the configuration of the optical transmission unit used in the 10G system. The figure (A) shows a transmitter and the figure (B) shows a receiver. FIG. 11 shows an example of the configuration of a transmitter used in the 10G system. In FIG. 12, 10
An example of the structure of the receiver used in a G system is shown.

The transmission section shown in FIG. 10 is an electric / optical conversion section 3.
2 and an optical booster amplifier 40.

The electric / optical conversion section 32 includes a drive circuit 80,
It has a modulator integrated light source module 82, an optical output control circuit 84 and a temperature control circuit 86 for stabilizing the optical output from the module 82 against ambient temperature changes and the like. The modulator integrated light source module 82 is configured by integrating a modulator and a laser diode. For example, an MQW-DFB-laser diode and an MQW electroabsorption modulator are integrated. Drive circuit 80
Drives the modulator at a transmission rate of 10 Gb / s. Although not shown in FIG. 10, a multiplexing circuit 44 shown in FIG. 11, which will be described later, is arranged in front of the drive circuit 80. The modulator modulates the optical output of the laser diode at 10 Gb / s according to the drive of the drive circuit 80. The light output control circuit 84 has, for example, a sensor that monitors the rear light output of the laser diode, and controls the driving of the laser diode according to the sensor output. Further, the temperature control circuit 86 has a temperature sensor, a thermoelectric cooling element, and the like,
The temperature of elements such as the module 82 is kept within a certain range.

The optical booster amplifier 40 includes an optical fiber amplifier 41 including an optical system and a light source, a monitor signal processing circuit 116 and an optical output stabilizing circuit 1 which are composed of an electric circuit system.
18 and. The optical fiber amplifier 41 includes, for example, an isolator 96 and an Er fiber 9 as shown in FIG.
8. WDM coupler WDM100 and isolator 1
08, the monitoring light source 114, and the excitation light source 104. This optical booster amplifier 40
Is the light output attenuated by the modulator, etc.
Increase without NF deterioration.

The supervisory signal processing circuit 116 comprises an optical fiber,
A fault monitoring process such as searching for a communication fault location such as 1R-REP, a fault mode, etc., and transferring the signal is performed.

The receiving section shown in FIG. 10 has an optical preamplifier 42.
And an optical / electrical conversion unit 34.

The optical preamplifier 42 includes an optical fiber amplifier 43 including an optical system and a light source, a monitor signal processing circuit 134 and an optical output stabilizing circuit 132 which are composed of an electric circuit system.
Have and. The optical fiber amplifier 43 is, for example, as shown in FIG. 4, an optical system including at least a wavelength division multiplexer WDM 120, an isolator 122, an Er fiber 124, an isolator 126, and a bandpass filter 136, a supervisory signal receiver 130, and an excitation light source. And 128. The wavelength multiplexing coupler WDM 120 separates the monitoring light signal from the signal light sent from the front and adds a pumping light source to the signal light. The optical preamplifier 42 increases the attenuated optical signal after the optical fiber transmission by the applied excitation light through the Er fiber 124 to a required optical output without NF deterioration. As the excitation light source 128, a light source having a wavelength of 1480 nm or 980 nm is used.

The optical / electrical converting section 34 converts the optical signal into an electric signal and equalizes and amplifies it to a predetermined signal amplitude while keeping it low noise, and the timing extracting circuit 5.
0, an identification circuit 166, and a photocurrent monitor circuit 142.

The equalizing / amplifying section 141 has a front end module 140 and a signal amplifying section 143.

The front-end module 140 has, for example, a light receiving element using a Pin photodiode and a preamplifier. The output of the preamplifier is the signal amplifier 1
43 and the photocurrent monitor circuit 142. The photocurrent monitor circuit 142 detects the average level of the optical input and sends it to the optical output stabilizing circuit 132 to control the gain of the optical preamplifier 43.

The signal amplification section 143 has an AGC amplifier 144.
And a peak value detection circuit 146 and a gain control circuit 148. The peak value detection circuit 146 is the AGC amplifier 1
An output from a peak value detection diode (not shown) built in 44 is compared with a reference voltage, and the error voltage is sent to a gain control circuit 148. The gain control circuit 148 controls the amplification gain of the AGC amplifier 144 based on this error voltage.

The timing extraction circuit 50 has a full-wave rectifier circuit 150, a dielectric filter 152 such as SAW, a phase shifter 154, and a limit amplifier 156. The timing extraction circuit 50 performs timing extraction from the received signal, generates a clock pulse required for the identification reproduction of the received signal in the identification circuit 166 in the subsequent stage, and supplies the timing clock signal to the separation circuit 46 described later. To do.

The discrimination circuit 166 discriminates the received signal by using the clock pulse and reproduces the signal.

Next, details of the configuration of the transmitter of the 10G system will be described with reference to FIG. The transmitter shown in FIG. 11 uses 622 Mb / s for 16 serial multiplexing and 9.9.
High-speed multiplexing circuit 45 for converting signals to 5 Gb / s (STM-64), electric / optical conversion unit 32, and optical booster amplifier 4
Has 0 and.

The high-speed multiplexing circuit 45 includes the clock generation circuit 4
8 and a multiplexing circuit 44. The high-speed multiplexing circuit 45 is composed of, for example, a Si integrated circuit. The electric / optical conversion unit 32 has a configuration as shown in FIG. 10 described above, and outputs the multiplexed signal,
The drive circuit 80 converts the level to obtain a modulated signal.

The optical booster amplifier 40 is the same as that shown in FIG.
Similar to the one shown in (1), it has an optical fiber amplifier 41 including an optical system and a light source, a monitor signal processing circuit 116 and an optical output stabilizing circuit 118 which are constituted by an electric circuit system. However, the optical booster amplifier 40 of this embodiment uses an optical fiber amplifier 41 having a configuration different from that shown in FIG. That is, the optical fiber amplifier 41 of the present embodiment includes the coupler 8 for extracting the optical input monitor light.
8 and a coupler 110 for extracting the optical output monitor light
And wavelength multiplexing coupler WDM 90, polarization combiner 92, isolator 96, Er fiber 98, wavelength multiplexing coupler WD
M100, polarization combiner 102 and isolator 108
And a monitoring light source 114, a pumping light source 94, a pumping light source 104, and a preliminary pumping light source 106. The output of a part of the optical signal taken out by the coupler 110 is directly input to the supervisory signal processing circuit 116, and the other part thereof is input to the optical output stabilizing circuit 118 via the bandpass filter 112.

This optical booster amplifier 40 includes a pump light source 9
The signal light from the electrical / optical conversion unit 32 is amplified by the forward pumping by 4 and the backward pumping by the pumping light source 104. That is, the pumping light from the pumping light source 94 is the coupler WD.
It is sent to the Er-doped fiber 98 via the M90 and the isolator 96, and is transmitted via the pumping light polarization beam combiner 102 from the pumping light source 104 and the wavelength multiplexing coupler WDM100 to Er.
The signal light is sent to the doped fiber 98, and the signal light is amplified by each. The light output is kept constant by the light output stabilizing circuit 118 based on the light output monitor.

The supervisory signal light from the supervisory light source 114 is inserted into the optical path of the signal light via the wavelength multiplexing coupler WDM100, and output via the coupler 110. Here, the wavelength of the monitoring light source 114 is set to the excitation light sources 94, 104, and 10.
6 wavelengths are set to be the same.

Next, details of the configuration of the receiver of the 10G system will be described with reference to FIG. The receiver shown in FIG. 12 includes an optical preamplifier 42 and an optical / electrical conversion unit 34.
And a separation circuit 46.

Optical preamplifier 42 and optical / electrical converter 3
4 is constructed similar to that shown in FIGS. 4 and 10 above. The separation circuit 46 uses 9.95 Gb / s (STM-
16) is separated from 64) to 622 Mb / s.

FIG. 13 shows an example of a transmitter used in the 2.4 Gb / s (A) system. The transmitter of the present embodiment has a basic configuration except that the multiple circuit part is different.
It is similar to that shown in FIG. The multiplexing circuit 44 of this embodiment multiplexes 150 Mb / s data into data having a transmission rate of 2.4 Gb / s.

FIG. 14 shows an example of a receiver used in the 2.4 Gb / s (A) system. The receiver of the present embodiment omits the optical preamplifier by using a highly sensitive avalanche photodiode for the photoelectric conversion unit 34. That is, it has the wavelength multiplexing coupler 120 and the isolator 122, the supervisory signal receiver 130 and the supervisory signal processing circuit 134, and the optical / electrical conversion unit 34.

The optical / electrical converting section 34 converts the optical signal into an electric signal, and at the same time, the equalizing amplifying section 170 which amplifies the signal to a predetermined signal amplitude while maintaining low noise, and the timing extraction circuit 5.
0, an identification circuit 166, and a photocurrent monitor circuit 142.

The equalizing / amplifying section 170 includes a front end module 174, a signal amplifying section 176, and a high voltage circuit 17.
2 and.

The front end module 174 has, for example, a light receiving element using an avalanche photodiode (APD) and a preamplifier. High voltage circuit 172
Driven by the output of. The output of the preamplifier is sent to the signal amplifier 176 and the photocurrent monitor circuit 142.

The signal amplification section 176 includes an AGC amplifier 144.
A peak value detection circuit 146 and a gain control circuit 148
And a main amplifier 180. The peak value detection circuit 146 compares the output from the main amplifier 180 with a reference voltage and sends the error voltage to the gain control circuit 148.
The gain control circuit 148 determines the AG based on this error voltage.
The amplification gain of the C amplifier 144 is controlled.

FIG. 15 shows an example of the configuration of the optical transmission unit used in the 2.4 Gb / s (A) system. Same figure (A)
Indicates a transmitter, and FIG. 1B shows a receiver.

The transmitting section shown in FIG. 15 is an electric / optical converting section 6
6 and an optical booster amplifier 74.

The electric / optical conversion section 66 includes a drive circuit 80,
A modulator integrated light source module 82, an optical output control circuit 84 and a temperature control circuit 86 for stabilizing the optical output from the module 82 against ambient temperature changes,
And a low frequency oscillator 78. The modulator integrated light source module 82 is configured by integrating a modulator and a laser diode. For example, an MQW-DFB-laser diode and an MQW electroabsorption modulator are integrated. The drive circuit 80 drives the modulator at a transmission rate of 2.4 Gb / s. Although not shown in FIG. 10, a multiplexing circuit 64 shown in FIG. 11, which will be described later, is arranged in front of the drive circuit 80. The modulator outputs the optical output of the laser diode to 2.4 Gb /
Modulate with s.

The optical booster amplifier 74 includes an optical fiber amplifier 75 including an optical system and a light source, and an optical output stabilizing circuit 1.
18 and. The optical fiber amplifier 75 is, for example, as shown in FIG. 9, an optical system including at least a wavelength multiplexing coupler WDM 90, a polarization combining unit 92, an isolator 96, an Er fiber 98, a wavelength multiplexing coupler WDM 100, a polarization combining unit 102, and an isolator 108. System and excitation light source 94
And a preliminary pumping light source 95, a pumping light source 104 and a preliminary pumping light source 106.

The receiving section used in the 2.4 Gb / s (B) system shown in FIG.
The electrical conversion unit 68 is included. In the receiver of this embodiment,
The use of a highly sensitive avalanche photodiode enables transmission without using a repeater.

The optical preamplifier 76 is the optical fiber amplifier 7
7 and a light output stabilizing circuit 132. The optical fiber amplifier 77 is, for example, as shown in FIG. 9, a wavelength multiplexing coupler 120, an isolator 122, and an Er fiber 1.
24, the isolator 126, and the bandpass filter 1
36 and an excitation light source 128 that outputs excitation light of 1480 nm or 980 nm.

The optical / electrical converting section 68 converts the optical signal into an electric signal, and at the same time, equalizes the amplifying section 170 which amplifies the signal to a predetermined signal amplitude while maintaining low noise, and the timing extraction circuit 5.
0, an identification circuit 166, and a photocurrent monitor circuit 142.

The equalizing / amplifying section 170 has a front end module 174 and a signal amplifying section 176.

The front-end module 174 has, for example, a light receiving element using an avalanche photodiode (APD) and a preamplifier. The output of the preamplifier is sent to the signal amplifier 176 and the photocurrent monitor circuit 142.

The signal amplification section 176 includes an AGC amplifier 144.
A peak value detection circuit 146 and a gain control circuit 148
And a main amplifier 180. The peak value detection circuit 146 compares the output from the main amplifier 180 with a reference voltage and sends the error voltage to the gain control circuit 148.
The gain control circuit 148 determines the AG based on this error voltage.
The amplification gain of the C amplifier 144 is controlled.

16 to 19 show other structural examples of the optical preamplifier and the optical booster amplifier used in the above-mentioned transmitter and receiver. These are respectively
The elements enclosed in the frame are contained in one package.

Next, the terminal station (LT-MUX) is carried out by accommodating the boards on which the respective constituent parts are mounted in a rack capable of forced air cooling. About the mounting state,
10GLT-MUX (2 systems / mounting) and 2.4G LT-MUX
External views of rack mounting (6 systems / mounting on rack) are shown in FIGS. 20 and 21, respectively.

As a mounting form, a forced air cooling method suitable for high-density mounting is used, and the division loss due to subdivision is small.
By adopting a 0 mm high package, 10 Gb /
An s transmitter, a 10 Gb / s receiver, an optical preamplifier, an optical booster amplifier, and a 2.4 G interface are mounted on one sheet. The inside of the station is equipped with 8 circuits of 150 Mb / s interface in a single sheet to achieve high density.

Also, the 2.4G LT-MUX in the B type system
(6 systems / mounting on rack) is also configured in the same manner as described above. The external view of the rack mounting is shown in FIG.

As for the power supply system, each power supply can be provided on the board. Also, some elements may be provided within a package that contains them.

Next, the terminal station (LTMUX (A
23) and FIG. 24 show the main specifications of (LTMUX) and (LTMUX (B type)). Note that these are just examples applied to the above-mentioned embodiment,
The present invention is not limited to this.

Next, referring to FIG. 25 and FIG.
The detailed structural example of 0GLT-MUX is shown. This 10GL
The T-MUX performs low-speed interface unit 200 (FIG. 25), two high-speed interface units 220 separated into 0-system and 1-system, and supervisory control in the device, as well as supervisory control serving as an interface to the operating system. / OpS interface unit 230, overhead interface unit 240 for inputting and outputting overhead signals outside the apparatus, and clock unit 250 for supplying a clock to the inside of the apparatus
(Above FIG. 26).

The low speed interface unit 200 includes
Intra-station interfaces 201 to 204 for 2 systems each of 0 system and 1 system, selectors 205 to 208 for selecting 0 system and 1 system, and a service controller for collecting monitoring information in the low speed interface unit, fault processing, etc. SVCONT) 209 and 210 and an in-unit monitoring control bus 211.

The high speed interface unit 220 includes
SOH units 221 to 224 that perform section overhead processing of STM-64, electric / optical conversion unit 10 GIFS 225 and optical booster amplifier unit 226 for transmission signals.
And an optical preamplifier unit 227 that amplifies an optical signal from the outside.
And an optical / electrical conversion unit 10GIFR228.

In this embodiment, STM-1 × 64 and S
Mutual demultiplexing conversion with the TM64 is performed, for example, as shown in FIG.

It is to be noted that 10 shown in FIG. 25 and FIG.
The functions of the respective parts of the GLT-MUX are shown as a list in FIGS. 27 and 28.

2.4G (A) system and 2.4
The system (B) can also be configured almost in the same manner as in the above figure.

Next, the structure of one embodiment of the submarine repeater will be described with reference to the drawings.

FIG. 30 shows a block diagram of the configuration of the submarine repeater. Further, FIG. 31 is a block diagram mainly showing the configuration of the optical fiber amplifier section of the submarine repeater.

In the present embodiment, each of the downlink and the uplink is 1
The system has a two-stage configuration including a low noise amplifying section DA1 and UA1 and a high output amplifying section DA2 and UA2, and is configured to simultaneously realize low noise and high output characteristics in a wide dynamic range. The low-noise amplifiers DA1 and UA1 function as an optical preamplifier, and this part is configured and functions similarly to the optical preamplifier shown in FIG. Further, the high-power amplifiers DA2 and UA2 function as an optical booster amplifier, and this part is configured and functions similarly to the optical booster amplifier shown in FIG. Further, an optical loopback function RBU using an optical switch is provided by connecting the interstages of the low noise amplification section DA1 and the high output amplification section DA2 and the interstages of the low noise amplification section UA1 and the high output amplification section UA2. ing. And each of these parts
Both the upstream and downstream optical amplifiers are integrally housed, and together with an electric circuit section for controlling them, they are housed in a common package as described later.

Further, it has an optical output monitor, an intermediate signal power monitor and an output open detection, and gain control and monitoring of the optical amplifier of each stage can be performed. Further, in this embodiment, the wavelength of 1.4
The configuration is such that a monitoring information signal of 8 μm can be received and transmitted.

Further, in the present embodiment, in consideration of being set on the seabed, the laser diode for the light source is used as a working standby structure of the cold standby system to achieve high reliability. This switching is configured so that both automatic switching and forced switching are possible. Further, both the switching of the optical switch of the loopback and the switching of the above-mentioned working standby can be operated by remote control from the terminal station LT-MUX by using the monitoring control signal of 1480 nm.

Next, further details will be described with reference to the drawings.

In FIG. 30 and FIG. 31, the low noise amplification section (optical preamplifier) DA1 on the down side and the optical preamplifier UA1 on the up side have the same configuration. Similarly, the downstream high-power amplifier (optical booster amplifier) DA2 and the upstream optical booster amplifier UA2 have the same configuration. Therefore, here, the configuration on the downstream side will be described.

The optical preamplifier DA1 is a composite coupler PFW.
DM 302 and supervisory signal receiver (S
1) 304, a working pumping light source (P1) 306 and a preliminary pumping light source (P1 ′) 308, and an Er fiber (EPF-
1) 310 and a composite bandpass filter (IBPF) 3
12 and.

As shown in FIG. 31, the composite coupler PFWDM 302 includes a wavelength division multiplexer WDM 302a, a polarization beam splitter (PBS) 302b, and an isolator 3.
And 02c in combination. This composite coupler 302 is
It has the functions of demultiplexing the monitoring optical signal sent through the optical fiber, multiplexing the pumping light, and performing optical isolation for preventing the return of the optical signal.

Composite Bandpass Filter (IBPF) 31
2 is a bandpass filter 312 as shown in FIG.
a and an isolator 312b arranged in the preceding stage thereof are combined and provided. The composite bandpass filter (IBPF) 312 performs ASE, removal of unabsorbed excitation light, and optical isolation.

The optical booster amplifier DA2 includes an isolator (ISO) 314 and an Er fiber (EPF-2) 31.
6, the composite coupler BBWDM 318, the supervisory signal light source (S2) 320 connected thereto, and the working pumping light source (P
2) 322 and a preliminary pumping light source (P2 ′) 324, a coupler (CPL-2) 326 for partially separating an optical signal, a bandpass filter 328 and a monitor light receiving element (M3) 332 connected thereto. A monitor light receiving element (M2) is further provided at the subsequent stage of the bandpass filter 328.
330 is arranged.

As shown in FIG. 31, the composite coupler BBWDM 318 includes a wavelength multiplexing coupler WDM 318a, a polarization beam splitter (PBS) 318b, and an isolator 3.
And 18c in combination. This composite coupler 318
It has the functions of demultiplexing the monitoring optical signal sent through the optical fiber, multiplexing the pumping light, and performing optical isolation for preventing the return of the optical signal.

Each light source 306, 308, 320, 324
Each have a laser diode as a light emitting element, and a driving circuit thereof.

The optical loopback function RBU is a loopback branch coupler (CPL) inserted in the downstream signal line.
-1) 344, a loopback branch coupler (CPL-1) 348 inserted in the upstream signal line, a loopback switching optical switch (D-SW) 342 on the downstream side,
Loopback switching optical switch (U-SW) 3 on the upstream side
46, a coupler (I-CPL) 340 that branches a part of the loopback optical signal, and this coupler (I-CPL) 3
Monitor light receiving elements (M1) 346 and 350 connected to 40.

As the electric circuit system, the same one is provided for each of the downstream system and the upstream system. This electric circuit system includes a supervisory signal processing circuit 352 and a light output stabilizing circuit 3
54 and.

With such a configuration, the optical signal input through the optical fiber is separated from the supervisory optical signal by the composite coupler 302 in the optical preamplifier section DA1.
The pumping light from the pumping light source 306 is combined and amplified by the Er fiber 310 by forward pumping. This light is input to the optical booster amplifier DA2 via the composite bandpass filter 312 and the coupler 344. The supervisory optical signal is detected by the supervisory signal receiver 304, and the detection signal is sent to the supervisory signal processing circuit 352.

In the optical booster amplifier DA2, the input optical signal enters the Er fiber 316 via the isolator 314, and is amplified by backward pumping there. This excitation light is supplied from the excitation light source 322 via the composite coupler 318. The backward pumping light is blocked by the isolator 314 from proceeding to the preamplifier side. In the composite coupler 318, in addition to the excitation light, the monitoring light signal from the monitoring light source 320 is multiplexed. In the subsequent stage, the coupler 326 splits a part of the signal light. The branched light is directly detected by the monitor light receiving element 332 and also detected by the monitor light receiving element 330 via the bandpass filter 328. The drive of the excitation light source and the monitoring light source is controlled based on the detection result.

By the way, the low noise amplifier DA1 (U
A1) stabilizes and uses the pumping light power so that the pumping light power is in a sufficiently high pumping state in order to realize low noise characteristics over a wide input signal light level range. High-power amplifier DA2 in the latter stage
(UA2) controls and uses pumping light power in order to realize stable high output characteristics over a wide input signal light level range.

The operation of the loopback function RBU will be described in the monitor control described later.

Regarding the details of the function of the relay device described above,
FIG. 32 shows a list.

The submarine repeater is suitable for constant current power feeding from the optical submarine power feeder of the landing station, which returns to the earth. Figure 3
3 shows an example of the configuration of the surge protection / power supply unit 56 (see FIG. 5). The diagram shows the surge protection circuit 360.
And a power supply circuit 366. Surge protection circuit 360
Has an arrester 362 and a Zener diode 364 for absorbing the surge.

Next, mounting of the submarine repeater will be described with reference to the drawings.

34 and 35 show the mounting state of the submarine optical amplification repeater. In the relay device of this embodiment, two 1R-REPs for ascending and descending are mounted on a rectangular substrate 400. In addition, the two substrates 1R-REP mounted on the substrate 400 are arranged as one set with the non-mounting surfaces facing each other. The substrate 400 is 100 mm in this embodiment.
× 600 mm is used. The input end I (D) in the down direction and the output end O (U) in the up direction are arranged on the input end side in the longitudinal direction of the substrate 400, and the output end O (D) in the down direction and the up direction in the multi-end side. The input end I (U) of is arranged. 34. In FIG. 34, the symbols attached to the respective constituent elements are those with D attached for downlink, and those with U attached for uplink.

Also, in the figure, the hatched portions are the optical preamplifier portion and the Er fiber bobbin 40.
It is 2. The bobbin 402 is arranged at the center of the substrate in the longitudinal direction. In the present embodiment, the downstream side optical preamplifier section and the upstream side optical preamplifier section are arranged symmetrically across the bobbin 402.

In this embodiment, four Er fibers 31 used for the upstream and downstream optical preamplifiers and optical booster amplifiers are used.
0 and 318 are wound around the same bobbin 402 and mounted. This reduces the mounting space for the Er fiber. Each optical component is spliced with a pigtail fiber with a bend radius of 30 mm and extra length. Although not shown, electric circuit systems such as a monitoring signal processing circuit and a light output stabilizing circuit are arranged in an empty space of the fiber surplus length processing unit. Further, an optical switch (D-SW) 3 for loopback is provided between the optical preamplifier output and the optical booster amplifier input.
42 and 346 (U-SW) are inserted. A coupler (I-CPL) 340 for intermediate power monitoring is arranged between the optical switches 342 and 346. Monitor couplers (M1) 346 and (M1) 350 are connected to the coupler 340 via an optical fiber. The composite couplers PFWDM and BBWDM mounted on the substrate 400 are both LT-MUX described above. In the same manner as the above, the signal light multiplexing (demultiplexing) and demultiplexing (separation) functions, the ports for the working and preliminary pumping light sources, and the 30 dB optical isolator are built in. And these are integrated and accommodated in the package. This allows
For example, it is possible to achieve a reduction in insertion loss between the input and output ports of 1 dB or less and pumping light coupling loss of 1.5 dB or less. In addition, the size can be reduced. further,
It is also possible to reduce the space for fiber surplus length processing required for connection when the above functions are individually configured.

Further, since the temperature rise of the optical amplification repeater unit can be suppressed to 10 ° C. or less with respect to the ambient temperature, the pumping light source module can have a structure without using a thermoelectric cooling element. Therefore, the size can be reduced.

Next, mounting of the submarine repeater of the present embodiment on the housing will be described with reference to the drawings.

Since this embodiment is installed on the seabed, functional conditions different from those installed on land are required for mounting. FIG. 36 shows the functional conditions.

The mounting structure used in this embodiment is shown in FIG.
Shown in. As shown in the figure, a pressure-resistant housing 502, a cable holding portion 504, and a connecting portion (gimbal) 506 are provided for mounting the above-described optical system and electric circuit system. At both ends of the pressure-resistant housing 502, the cable retaining portions 50
4 and the connecting portion (gimbal) 506 are fixed to each other by using a submarine optical cable coupling 508. The optical fiber cable 6 is attached to the cable retaining portion 504. As shown in FIG. 34, the optical system and the electric circuit system are mounted on a substrate 400, and further, a pair of the substrates 400 on which these are mounted constitute a circuit unit 500 and are housed in a pressure-resistant housing 502. It

The pressure-resistant housing 502 is constructed as follows.

(A) Material Since the pressure-resistant housing 502 is installed at a maximum water depth of 8000 m, it is required to withstand a strong water pressure and have a long-term corrosion resistance of 25 years. Further, it is desirable to use a material that does not cause corrosion of dissimilar metals with the material of the cable coupling 508. In this embodiment, the cable coupling 508 and the pressure-resistant housing 502 are both Be-
It is made of Cu alloy. The composition of the Be-Cu alloy used here contains 97.6% of copper, 1.6 to 1.8% of beryllium, and also contains cobalt, iron, nickel, silicon and the like. The mechanical properties of this alloy are shown in FIG. In addition,
The amount of seawater corrosion is considered to be approximately 20 μ / year or less.

(B) Dimensions (i) Wall thickness of pressure-resistant housing body The thickness of the pressure-resistant housing 502 can be obtained by a thick-wall theory. Regarding pressure vessel damage, there are (1) maximum principal stress theory, (2) maximum shear stress theory, and (3) maximum shear strain energy theory. Here, ductile materials such as mild steel and copper alloys
It should be determined according to the theory of shear strain energy. Assuming that the pressure-resistant housing 502 has a cylindrical structure as shown in FIG. 39A, the minimum wall thickness that does not damage is given by the following equation.

[0147]

[Equation 1]

Given that the outer diameter of the circumference of the pressure-resistant housing is φ320, the minimum wall thickness can be calculated from the water pressure: 7845 N / cm ² (800 kgf / cm ² ) and the material allowable stress: 588 N / cm ² (60 kgf / mm ² ). , About 18 mm. The wall thickness can be set to 25 mm in consideration of the margin safety factor of the amount of corrosion. Therefore, the cylinder inner diameter is φ270.

(Ii) Thickness of End Face of Pressure Resisting Case 502 As shown in FIG. 39 (B), the end face of pressure resistant case 502 is provided with a step 510 on the end face of the body of pressure resistant case 502.
As a structure in which the end plate 512 is fitted, it receives water pressure. It is necessary to determine the size of the end plate 512 so that the stress in the shoulder portion of the step 510 falls within the material allowable limit. The dimensions are given by:

[0150]

[Equation 2]

In the above formula (2), σ = 588 N / mm ² (60 kgf / mm ² ) P = 7845 N / cm ² (800 kgf / cm ² ) d = φ270 mm From the outer diameter D of the end plate 512, D ≧ φ290 mm.

Regarding the thickness of the end plate 512,
From the condition that 12 is fitted into the end face of the pressure-resistant housing 502 and welded circumferentially, the end face plate thickness is t, and a constant (welding structure c = 0.4) determined by the flat plate mounting method is given by the following formula. Given.

[0153]

[Equation 3]

In the above formula (3), σ = 588 N / mm ² (60 kgf / mm ² ) P = 7845 N / cm ² (800 kgf / cm ² ) d = φ270 mm, and thus the end face plate thickness t is 63 mm.

(C) Airtight structure (i) Pressure-resistant housing body and end face plate The end face plate 512 is fitted into the body of the pressure-resistant housing 502 and sealed by circumferential welding to maintain airtightness. The welding lip has a maintainable structure.

(Ii) Cable Introducing Section A cable introducing section 514 for introducing a fiber or a power supply line is provided at the end of the pressure-resistant housing. The cable introduction portion 514 is required to have high airtightness as well as water pressure resistance, electrical insulation and the like. The airtight basic structure of the cable introducing part 514 is received by a metal disk 516 for water pressure resistance.
This is electrically isolated from the pressure-resistant housing by a polyethylene-molded insulator. To prevent creep failure due to water pressure received by the pressure receiving portion of the disc 516, a taper is provided in the mold portion behind the disc 516 to relieve stress. In addition, the cable introduction portion 514 and the end plate 5
An O-ring 518 is used for sealing to and from 12. Further, a metal cone 520 is provided on the outer circumference of the connecting portion between the cable introducing portion 514 and the optical fiber cable 6.

Next, the circuit unit 500 housed in the pressure resistant casing 502 will be described.

(A) Division Method In this embodiment, as described above, the transmission line system is constructed in units of 6 systems. Circuit unit 5
As described above, 00 is configured by combining two boards 400 on which one system is mounted. Therefore, in housing in the pressure resistant housing 502, 6 systems are divided into 3 parts to form a 3 circuit unit 500. 3 circuit unit 5
00 indicates the circuit unit housing 522 as shown in FIG.
Inside, arrange in a triangular shape. That is, a maximum of 6 SYS can be accommodated by 2 SYS / circuit unit.

The circuit power supply unit 56 is arranged on the outer portion of any one of the three circuit units 500. This circuit power supply unit 56, as shown in FIG.
And a surge protection circuit 360. The power supply unit 56 is provided outside in order to improve heat dissipation.

The circuit unit housing 522 has a triple structure as shown in FIG. That is, it has a circuit unit outer casing 524 and a circuit unit inner casing 526 arranged inside thereof, and an insulating layer 528 is provided between them.
Are placed.

The housing of the circuit unit 500 is performed, for example, as shown in FIG. That is, the pedestal 538 is provided on the inner circumference of the circuit unit outer casing 524, and the mounting plate 540 on which the circuit unit 500 is mounted is fixed to the pedestal 538 by screwing or the like. As a result, each circuit unit 500 is connected to the circuit unit outer casing 52.
4 is arranged so as to be located on each side of the equilateral triangle.

(B) Heat dissipation buffer structure The circuit unit 500 mounted in the submarine repeater reduces the temperature rise due to heat generation from the necessity of ensuring a predetermined reliability, and, at the time of laying, an external pressure-resistant casing. There is a need for a heat dissipation / buffer structure that can alleviate the impact on the body. For this reason, as shown in FIGS. 42 and 43, a leaf spring 530 for improving heat conduction and a rubber buffer 532 for cushioning impact are attached between the pressure-resistant housing 502 and the circuit unit housing 522.

The leaf spring 530 has a U- or J-shaped channel structure with a shallow cross-sectional structure. This leaf spring 530
Are configured to be biased in the direction in which the channel expands, and a plurality of them are arranged between the circuit unit housing 522 and the pressure-resistant housing 502 so that elasticity acts in the radial direction of the circuit unit housing 522. To be done.

(I) Heat dissipation structure Most of the heat generated in the circuit unit 500 flows in the radial direction and is transferred from the pressure-resistant housing 502 to seawater. This heat equivalent circuit model is shown in FIG.

In this thermal equivalent circuit model, the main cause of thermal resistance is from the heating element to the circuit unit inner casing 5
26 between the circuit unit outer housing 524 and the pressure resistant housing 502. In this embodiment, the thermal resistance of each is further reduced. That is, between the heating element and the circuit unit inner casing 526, as shown in FIG. 45, the respective circuit units 500 arranged by dividing the space along the inner periphery of the circuit unit inner casing 526 into three are arranged. The heating element 534 is attached to the circuit unit inner housing 526 via a leaf spring (heat conduction plate) 536. In addition, a leaf spring is provided between the circuit unit outer casing 524 and the pressure-resistant casing 502.
A (heat conduction plate) 530 is attached to promote heat conduction.

The number of leaf springs (heat conduction plates) 530 is determined, for example, with the target thermal resistance between the circuit unit outer casing 524 and the pressure-resistant casing 502 being 0.02 ° C./W. Heat conduction between the circuit unit housing 522 and the pressure resistant housing 502 is shown in FIG.

(Ii) Cushion structure As shown in FIG. 42, the rubber cushion 5 is used as a cushion due to the distance between the pressure resistant casing 502 and the circuit unit casing 522.
32 is used to mitigate the impact when laying. The rubber shock absorber 532 is formed in a ring shape and includes the circuit unit housing 52.
It is fitted on the outside of 2.

(Iii) Surge Resistant Structure As described above, the circuit unit casing 522 has the triple structure of the circuit unit outer casing 524, the insulating layer 528 and the circuit unit inner casing 526 as shown in FIG. It has a structure. With such a structure, the surge resistance is secured.

Next, the cable retaining portion 504 will be described.

The cable retaining section 504 is a section for connecting the submarine optical cable 6 and the repeater 2 while ensuring sufficient strength against an external force received during laying and laying. As shown in FIG. 47, the cable retaining portion 504 has a cylinder portion 542 that performs connection processing and a retaining structure portion 544 that retains the cable 6.

The cylinder portion 542 has a structure having water pressure resistance and airtightness equivalent to those of the pressure resistant case. The cable retaining structure 544 securely fixes the strength member of the cable by the wedge effect while protecting the optical fiber 6.

Next, the connection (gimbal) section 506 will be described.

The gimbal portion 506 is used so that the pressure resistant casing and the cable holding portion can be smoothly wound around the drum of the laying machine. Therefore, the universal joint structure is adopted. As specific structures, there are a gyro structure capable of achieving a large tensile strength and a large rotation angle, which have a proven track record in submarine repeater housings, and a structure capable of adjusting a bending angle without giving a twist to an optical cable. The structure of the gimbal is shown in FIGS. 48 and 49 (A).

The feature of the structure shown in FIG. 49 is, firstly, that the bending angle can be limited. That is, stoppers are provided on the rotary shafts a and b. Second, it can be compact. Thirdly, the center of the rotation axis and the hole H are offset as shown in FIG. 7C, and the cable bending is smoother than in the case without offset shown in FIG. Can be

Next, the supervisory control system in the optical transmission system of the present invention will be described.

First, FIG. 50 shows main specifications of the supervisory control in the submarine type A system. The configuration of the supervisory control system is shown in FIG.

The supervisory control system is controlled under the control of the host operating system 600, as shown in FIG.

In the LT-MUX 10, the monitor control unit 602 and the failure section evaluator 60 are the necessary elements for the monitor control.
4 and a main signal transmission unit 606 for performing optical transmission. The monitoring control unit 602 is, for example, the monitoring control unit 36 in FIG. 3 or the monitoring control interface 2 in FIG. 25.
30 corresponds. The main signal transfer unit 606 corresponds to, for example, the electrical / optical conversion unit 32, the optical / electrical conversion unit 34, the optical booster amplifier 40, and the optical preamplifier 42. The monitoring control unit 602 includes an operating system interface 601 and an alarm controller interface 603.
And are connected.

The 1R-REP2 has a supervisory control unit 608 and a main signal transmission unit 610 as elements necessary for supervisory control. The monitoring control unit 608 corresponds to, for example, the monitoring control unit 54 in FIG. The main signal transfer unit corresponds to, for example, the optical fiber amplifier 52.

FIG. 52 shows the network monitoring control items executed in such a configuration. In FIG. 52, the items executed in each of the submarine terminal equipment (A type) and the optical amplification repeater are shown separately as monitoring items and control items.

Next, FIG. 53 shows the configuration of the monitor control unit 602. The monitor control unit 602 corresponds to the monitor control interface 230 shown in FIG. Further, the function sharing is shown in FIG. Further, FIG. 55 to FIG.
A list of functions of the supervisory control system is shown in.

Next, the supervisory control signal in the seabed A system will be described.

The supervisory control signal is wavelength-multiplexed with the main signal and transmitted. Therefore, it is possible to remotely monitor and control 1R-REP2. The monitor control signal has the following features.

1) The monitoring control signal (128 kb / s) is set to 1.48 μ
m Light is transmitted. The supervisory control signal has a frame length of 256
The byte and frame periods are 16 msec.

2) The inner area of the frame is divided into 16-byte units, and an area is assigned to each 1R-REP. In addition, the 16 bytes are divided into two areas and allocated to the EAST side access and the WEST side access. FIG. 59 shows an example of the frame structure of this supervisory control signal.

The supervisory control unit of the terminal station and the supervisory control unit of the 1R-REP execute, for example, the following surveillance and control in response to this supervisory control signal.

1) The above area of the reception monitoring control signal is accessed, and when an alarm is detected, a bit is set and sent to the subsequent stage.

2) Read and execute instructions such as loopback.

3) Monitor for power failure of 1R-REP. When the power is turned off, it will be notified to the latter stage.

4) The output level of the LD is set by the supervisory control signal, thereby realizing bit rate free transmission.

5) A loopback execution / cancellation instruction is output to the relay device in response to the monitor control signal.

Next, FIG. 60 shows the alarm transfer method. In this embodiment, the alert processing is performed by setting the alert detection / transfer layer to the 1R section layer, the 3R section layer, and the LT.
Divide into four sections, the section layer and the path layer.
Each will be described below.

1) 1R section layer Handles alarms detected by 1R-REP. The result is transferred by the supervisory control signal. The processing items include, for example, those listed below.

A) Optical fiber disconnection: Main signal and supervisory control signal input disconnection due to optical fiber disconnection b) Main signal input disconnection: Main signal input disconnection due to 1R-REP failure in the previous stage c) Supervisory control signal Input disconnection: Main signal input disconnection due to failure of 1R-REP in the previous stage d) Monitor control signal LOF (Loss of Frame): Monitor control signal out of frame e) Monitor control signal FCS (Frame Check Sequence) error・ ・
Code error is detected by inspecting FCS of supervisory control signal F) 1R section failure REP identification ... Severe failure detected 1
The R-REP writes its own ID in a predetermined byte provided in the monitor control signal and generates a monitor control signal. This realizes the SDH F1 byte function.

2) Perform processing related to RSOH of the 3R section layer STM frame. The processing items are listed below.

A) Main signal LOF ・ ・ ・ Detects main signal frame desynchronization by A1 and A2 bytes.

3) LT section layer Performs processing related to MSOH of STM frame.

4) Path Layer Performs processing related to VC-3 / 4 POH of STM frame.

The alarm of the 1R section reaches the LT-MUX by relaying another 1R-REP by the supervisory control signal.

[0200] Next, the maintenance operation of the relay device of the seabed A system will be described. For maintenance and operation of the submarine A system, various optical repeaters are remotely controlled, and a monitoring optical signal with a wavelength of 1.48 μm is used as 1R relay section overhead in order to easily identify a failure location for each 1R relay section. Below, 1R relay section monitoring, 1.4
The processing of the 8 μm supervisory control signal will be described. The supervisory control described here can be similarly performed in the preamplifier section and booster amplifier of the LT-MUX.

FIG. 61 shows an example of the supervisory control items in the relay device. For the monitoring control items shown in FIG. 61, for example, the following monitoring control is performed. That is, the monitoring control unit (monitoring control signal processing unit) of the relay device is
The locations indicated by circled numbers in FIG. 30 are monitored to perform optical amplification gain control (optical output stabilization control) at each stage, and also perform functions such as preventive maintenance and failure location identification at the time of failure.

Main signal light having a wavelength of 1552 ± 1 nm and 1480 nm
PF-W from the input light that is combined with the wavelength supervisory control optical signal
This is a supervisory optical signal demultiplexed by the DM 302 and received by the supervisory signal receiver 304. Supervisory signal receiver 3
04 performs 3R processing on this signal, converts it into an electric signal, and sends it to the supervisory signal processing circuit to detect a supervisory signal input disconnection.

: Loopback circuit RBU to CPL3
The monitor light is branched by 40 and used as gain control, input state monitoring, and intermediate output power monitor.

: Monitor light obtained by branching the optical output of the high-power amplifier section by the CPL 326, taken out through the BPF 328, and used for gain control and output state monitoring.

C: the reflected light from the output end of the high-power amplifier
This is the monitor light branched via the PL 326 and performs output open detection.

[0206]: L together with output stabilization control of the pumping light source
Perform D state monitoring.

This is the transmission of the supervisory control signal, which is converted into an optical signal by the supervisory control light source having a wavelength of 1480 nm, and multiplexed by the BB-WDM 318 with the optical output of the high-power amplifier. Further, here, the monitoring light source LD state monitor and the monitoring signal output disconnection are detected.

In the relay device of this embodiment, it is necessary to assume various types of main signal input / output disconnection, supervisory signal input disconnection, input fiber disconnection, etc. as transmission line alarms. With these, it is possible to identify the failure location by the decision logic that integrates ,,. Other monitoring points are also used to detect device failure in the optical amplification repeater and preventive maintenance of the device.

In the present invention, as described above, there is an embodiment in which the monitoring light source and the excitation light source are configured to have a spare in addition to the current one. In such an embodiment, an instruction from the host device is sent from the terminal station on the supervisory signal light and sent, and the signal is extracted as described above, based on this, the supervisory control unit decodes the instruction content, The designated light source, for example, the excitation light source is switched between the working and standby states. The switching can be performed, for example, by switching the drive circuit of the light source. Further, this switching may be automatically performed in the device. That is, the state of the light source is determined based on the monitor state of the light source (LD) in the above, and the working mode and the standby mode are switched if necessary.

Further, in the present invention, the 10G system and the 2.4G system have the same basic configuration, so that the 10G system and the 2.4G system are configured so that they can be used in advance. It is possible to switch to the other system. In this case, the most important item that needs to be switched is the switching of the power of the light source such as the excitation light source (output level setting). In this embodiment, the switching control can be performed by transmitting the switching instruction from the terminal station by mounting the switching instruction on the monitoring optical signal, separating it by the relay device, decoding it, and executing it in the same manner as described above. ..

In addition to this, remote control for failure point evaluation, loopback, etc. is performed. Those will be described later.

FIG. 62 conceptually shows a control system of the supervisory control for the above-mentioned submarine repeater. In addition,
In the figure, W-E and E-W mean west to east and east to west, respectively, and distinguish the down and up of signals.

Further, FIG. 63 shows details of the supervisory control function of the relay device. Here, the LD drive control circuit and the LD switching unit 700 are shown as the monitoring control unit. In the LD drive control circuit and LD switching section 700,
Based on various monitor information, information such as LD temperature, LD current, input state, intermediate power collection state, output state and output release is output. These pieces of information are transmitted to the host device.
Also, stop the output from the host device, set the output level, LD
An instruction such as switching is input.

As shown in FIGS. 51 and 62, the seabed 1
The R relay device 2 is connected to the OpS system 600 of the host device through the operating system interface 601 of the LT-MUX 10 of the landing station. For this remote monitoring control, monitoring signal light with a wavelength of 1.48 μm is used.

The supervisory control signal is used as 1R relay section overhead for 1R relay section monitoring and relay remote control, and is terminated for each 1R relay section as shown in FIG.

In the submarine repeater 2, it is necessary to simplify the control circuit as much as possible from the viewpoint of reliability and downsizing, and since the information transfer is closed between the repeater 2 and the LT-MUX 10. , Uses a simplified signal transfer method different from the remote monitoring and control method for land systems. As shown in FIG. 59, a fixed length frame with a fixed cycle is used.
A time slot is assigned to each relay device, and the supervisory control information of each relay device is stored here in the bit assignment format.

In the relay device, the monitoring result and the operation state are constantly and regularly transferred to the LT-MUX 10, and the LT-M
In UX10, failure judgment, event processing, history recording,
Performs processing such as OpS message communication. Also, OpS
The control command from 600 is converted into a relay control signal by the LT-MUX 10 and sent to the relay device 2. Access from the LT-MUX to the relay device 1Sys is possible from both WE and EW, and dual monitoring and control routes are provided. FIG. 63 shows the supervisory control function configuration in this relay device.

The supervisory control information transfer in the 1R-REP supervisory control not only notifies the downstream of the fault of the 1R-REP, but also facilitates the failure point determination for each 1R relay section and enables the remote control of the 1R-REP. Each one to do
A method of terminating the supervisory control signal light with R-REP is used.

Further, the method of the present invention has an advantage that the monitoring information can be transmitted by one wavelength even if the number of relay devices increases.

(1) Selection of wavelength If the wavelength of the monitor signal is out of the band of the optical amplifier, the influence on the main signal due to the saturation of the optical amplifier can be avoided. Here, a wavelength of 1.48 μm is used. this is,
This is because the loss of the transmission line fiber is as small as the main signal wavelength and the wavelength division multiplexer (WDM) can be shared with the multiplexer / demultiplexer of the pumping light.

(2) Selection of Transmission Code The supervisory control signal is transmitted using the CMI code. CMI
By adopting the code, it is possible to suppress the DC component and zero continuity, and the frame synchronization circuit based on the code violation can configure the frame synchronization circuit with a relatively small amount of hardware.

(3) Supervisory Control Light Transmission / Reception Processing The construction of the supervisory control light transmission / reception processing system is performed as described above.

Each 1R-REP receives the monitoring information signal,
By transmitting after the reproduction processing, the last receiving terminal station can know which repeater or fiber has an abnormality. That is, the following items can be monitored by the route of the circled numbers shown in FIG.

A. Input state a-1 Input signal disconnection () a-2 Input signal power (more estimated) b. Output state b-1 Output signal disconnection () b-2 Output open () b-3 Output signal power () c. Intermediate output state c-1 Intermediate output signal power, output cutoff () d. Repeater state d-1 pump LD temperature, monitor current, bias current () d-2 monitor LD temperature, monitor current, bias current () d-3 pre-stage / post-stage optical amplifier gain (estimated) d-4 power supply () Next, the failure section evaluation method of the seabed A system will be described.

The submarine section failure evaluation method is based on the failure evaluation in 1R relay section units by the main signal loopback.
As an auxiliary means, the cable breakage position is specified by measuring the resistance of the feeding conductor. In addition, OTDR (Optic
Al Time Domain Reflectometry) is used to measure the fault position of the optical fiber from the landing station to the nearest 1R-REP.

For the evaluation of the failure section of the seabed A system,
The main signal loopback in the 1R repeater is mainly used. However, in the evaluation of the failure section, it is necessary to properly use a plurality of methods depending on the availability of power supply to the 1R repeater, the position of the evaluation section, and the like.

The main signal loopback is performed by switching the optical switch in the repeater. Then, the activation, notification, and cancellation of loopback are transmitted from the landing station on the monitoring signal. Therefore, in the main signal loopback, when the power supply to the 1R repeater is possible, it is possible to evaluate the failure section for each fiber core in the 1R relay interval unit. Detailed means for implementing loopback will be described later.

Further, when a failure occurs in the power feeding conductor of the cable and it is impossible to feed power to the 1R repeater, it is possible to estimate the failure occurrence point by measuring the DC resistance of the power feeding conductor from the landing station. Resistance between cable break point and ground, that is,
It has been reported that the value of the fault resistance is proportional to the nth root of the measured current (Ishida et al. “Improvement of fault location measurement method in submarine cables” KDD International Communication Research No. 102).
p.41), which has been used as a method of fault location evaluation.

[0229] In addition, OTDR (Optical Time) is used for the failure evaluation of the section from the landing station to the first repeater (first section).
By connecting the Domain Reflectometry), it is possible to evaluate the failure point with an accuracy of several meters.

FIG. 64 is a block diagram of the fault section evaluation system installed at the landing station. The failure section evaluation system includes a monitoring device 800, a power feeding device 802, and a main signal rack 8
08 and a failure section evaluation device 810.

The cable 6 is terminated at the landing station 10,
The electric conductor portion is connected to the power feeding device 802, and the optical fiber core wire is connected to the main signal frame 808. When an abnormality in the transmission path is detected by the section overhead processing of the main signal, the monitoring system sequentially activates the main signal loopback in the 1R repeater, and evaluates the failure section for each relay section.
When loopback cannot be performed due to power supply abnormality, the electric conductor part connected to the power supply device 802 is switched to the DC resistance measurement part 812 of the failure section evaluation device 810 to estimate the failure position. In addition, the OTDR measuring device 814
Can be connected to a fault fiber to find the fault point in the first section.

Next, the optical loopback system will be described with reference to FIG. FIG. 65 shows only the part necessary for loopback in the configuration in the relay device shown in FIG. 31 described above.

The following procedure is used to loop back the downlink signal.

(1) The supervisory signal system is used, and the pumping light source output of the Er-doped fiber 310 in the desired submarine optical amplification repeater is dropped by remote control from the submarine optical terminal transmitter.

(2) Using the supervisory signal system, the optical switch 342 of the submarine optical amplification repeater is switched to the 2 side and the optical switch 346 of the submarine optical amplification repeater is switched to the 4 side by remote control from the submarine optical terminal transmitter.

(3) By this operation, the downstream signal passes through the 3 dB coupler 344, the optical switch 342, the optical switch 346 inserted in the downstream signal system, and the 3 dB coupler 348 inserted in the upstream signal system, and loops. Back.

A similar procedure may be used to loop back the upstream signal.

(1) Using the supervisory signal system, the pump light source output of the Er-doped fiber 310 in the desired submarine optical amplification repeater is dropped from the submarine optical terminal transmitter.

(2) Using the supervisory signal system, the optical switch 34 of the submarine optical amplification repeater from the submarine optical terminal transmitting device.
2 is switched to the 1 side, and the optical switch 346 is switched to the 3 side.

(3) By this operation, the upstream signal passes through the 3 dB coupler 348, the optical switch 346, the optical switch 342 inserted in the upstream signal system and the 3 dB coupler 344 inserted in the downstream signal system, and loops. Back.

In the normal service state, the optical switch 342 is set to the 2 side and the optical switch 346 is set to the 3 side. At this time, the intermediate optical power monitor 350 monitors the output of the Er-doped fiber 310 for the downstream signal, and the intermediate optical power monitor 346 monitors the output of the Er-doped fiber 310 for the upstream signal.

The feature of this system is that the loopback signal is
The point is that it is taken out from the middle of the stage optical amplifier. By doing so, (1) there is no deterioration in NF as compared with the method of extracting the loopback signal from the input side of the optical amplifier, and (2) the method of extracting the loopback signal from the output side of the optical amplifier. Compared with, there is an advantage that a large output power can be obtained (compared under the same excitation power).

Next, the supervisory control system in the submarine B type optical transmission system will be described.

FIG. 66 shows the configuration of an embodiment of the supervisory control system of the submarine B type optical transmission system. The monitoring control system is shown in Fig. 6.
As shown in FIG. 6, the upper operating system 600
Controlled under the control of.

In the LT-MUX 10, the elements necessary for the supervisory control are the supervisory control unit 602 and the failure section evaluator 60.
4 and a main signal transmission unit 606 for performing optical transmission.

FIG. 67 shows network monitoring control items executed in such a configuration. In FIG. 67, the items to be executed in the submarine terminal device 10 are divided into monitoring items and control items.

In the optical transmission system on the seabed B, monitoring control is basically performed via OpS. CC for supervisory control
The SOH part of the ITT STM frame is used. As an alarm processing method, the alarm detection / transfer layer is divided into 3R section layer, LT section layer, and path layer. FIG. 68 shows an alarm transfer method. Each will be described below.

1) Perform processing related to RSOH of the 3R section layer STM frame. The main processing items are as follows. a) Main signal LOF ・ ・ ・ Detection of main signal frame out-of-sync by A1 and A2 bytes 2) Processing of MSOH of LT section layer STM frame. The main processing items are as follows. a) Error rate deterioration detection: MER and ERR MON using B2 byte
3) Perform processing related to VC-3 / 4POH of the path layer STM frame.

Next, the failure section evaluation method for the seabed B system will be described.

The submarine section failure evaluation method is based on the failure position evaluation by OTDR. As an auxiliary means, the cable breakage position is specified by measuring the resistance of the feeding conductor.

In this embodiment, OTDR (Optical Time Domain Reflect) is used to evaluate the failure section of the seabed B system.
ometry) is used. In addition, DC resistance measurement of the cable conductor is also used to estimate the failure point. The failure section evaluation function is shown in FIG.

The specifications of the OTDR used are shown in FIG. By measuring the level of backscattered Rayleigh scattered light, it is possible to evaluate a fault point up to 150 km from the landing station with an accuracy of ± 5 m. Since the maximum relay distance in the submarine B system is 300 km, the fault sections are determined by performing a fault assessment for each half of the fiber from both landing stations.

When the cable is broken, the failure point can be estimated by measuring the DC resistance of the cable conductor.

FIG. 69 shows an example of the configuration of the failure section evaluation system used in this embodiment. This system will be installed at the landing station. The cable 8 is terminated at the landing station, and the electric conductor portion is the cable position search signal generation portion 804.
The optical fiber cores are connected to the main signal rack 808, respectively. When an abnormality of the transmission path is detected by the section overhead processing of the main signal, the electric conductor portion connected to the cable position search signal generation unit 804 is switched to the DC resistance measurement unit 812 by the switch 805, and the fault position is estimated. To do. Further, the OTDR measuring device 814 is connected to the faulty fiber to accurately find the faulty point.

The embodiment described above is merely an example, and the present invention is not limited to this.

[0256]

As described above, according to the present invention,
An optical fiber cable is laid on the seabed to enable high-speed transmission and to monitor and control failures etc. remotely. In particular, the relay device installed on the seabed can be monitored and controlled from a device on land, which is excellent in maintainability.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a relay transmission network to which the present invention is applied.

FIG. 2 is a block diagram showing an example of the configuration of one of the large nodes used in the network that is connected to the submarine optical transmission system.

[FIG. 3] 10G of the submarine high-speed optical transmission system of the present invention
The block diagram which shows the outline of a structure of one Example of the b / s (A type) system.

FIG. 4 is a block diagram showing an outline of the overall configuration of the system of the above embodiment.

FIG. 5 is an explanatory diagram showing an outline of a relay device used in the above embodiment.

[Fig. 6] 2.4 of the high-speed submarine optical transmission system of the present invention
The block diagram which shows the outline of a structure of one Example of a Gb / s (A type) system.

FIG. 7 is a block diagram showing an outline of the overall configuration of the system of the above embodiment.

FIG. 8: 2.4 of the undersea high-speed optical transmission system of the present invention
The block diagram which shows the outline | summary of the structure of one Example of a Gb / s system (B type system).

FIG. 9 is a block diagram showing an outline of the overall configuration of the system of the above embodiment.

FIG. 10 is a block diagram showing a configuration of an optical transmission unit in an embodiment of the 10 Gb / s (A type) system.

FIG. 11 is a block diagram showing a configuration of a transmitter in one embodiment of the 10 Gb / s (A type) system.

FIG. 12 is a block diagram showing a configuration of a receiver in an embodiment of the 10 Gb / s (A type) system.

FIG. 13 is a block diagram showing a configuration of a transmitter in one embodiment of the 2.4 Gb / s (A type) system.

FIG. 14 is a block diagram showing a configuration of a receiver in an example of the 2.4 Gb / s (A type) system.

FIG. 15 is a block diagram showing a configuration of an optical transmission unit in an example of the 2.4 Gb / s (B type) system.

FIG. 16 is a block diagram showing the configuration of an embodiment of an optical booster amplifier used in the present invention.

FIG. 17 is a block diagram showing the configuration of an embodiment of an optical preamplifier used in the present invention.

FIG. 18 is a block diagram showing the configuration of another embodiment of the optical booster amplifier used in the present invention.

FIG. 19 is a block diagram showing the configuration of another embodiment of the optical preamplifier used in the present invention.

FIG. 20: Seabed A type 10GL used in the present invention
Explanatory drawing which shows an example of the rack mounting state of T-MUX.

FIG. 21: Seabed A type 2.4G used in the present invention
Explanatory drawing which shows an example of the rack mounting state of LT-MUX.

FIG. 22 shows a seabed B type 2.4G used in the present invention.
Explanatory drawing which shows an example of the rack mounting state of LT-MUX.

FIG. 23 shows a seabed type A LT-M used in the present invention.
Explanatory drawing which shows an example of the main specifications of UX.

FIG. 24 is a submarine B-type LT-M used in the present invention.
Explanatory drawing which shows an example of the main specifications of UX.

FIG. 25: 10GLT-MU used in the present invention
The block diagram which shows a part of example of X apparatus structure.

FIG. 26: 10GLT-MU used in the present invention
The block diagram which shows the remainder of an example of the apparatus structure of X.

FIG. 27: A type 10GLT- used in the present invention
Explanatory drawing which displays a part of an example of the function of MUX.

FIG. 28: A type 10GLT- used in the present invention
Explanatory drawing which displays a part of an example of the function of MUX.

FIG. 29 is an STM-1 × 64 and S in the optical terminal device.
Explanatory drawing which shows the relationship between TM-64 demultiplexing and in-station interface implementation.

FIG. 30 is a block diagram showing the configuration of an example of a submarine optical amplification repeater used in the present invention.

31 is an explanatory diagram showing a configuration of an optical system portion of the relay device in FIG.

FIG. 32 is an explanatory diagram showing the function of a relay device used in the present invention.

FIG. 33 is a block diagram showing an example of a configuration of a power supply unit used in a relay device.

FIG. 34 is a plan view showing a mounting structure of an optical amplifier circuit of a relay device.

FIG. 35 is a side view thereof.

FIG. 36 is an explanatory diagram showing functional conditions related to an implementation layer of a relay device.

FIG. 37 is a front view showing the outer appearance of an embodiment of a pressure-resistant housing that houses the circuit unit of the relay device.

FIG. 38 is an explanatory diagram showing mechanical characteristics of a beryllium copper alloy used in the structure of the pressure resistant casing.

FIG. 39 is an explanatory view for determining the wall thickness and the end face structure of the pressure resistant casing.

FIG. 40 is a cross-sectional view showing the structure of a cable introducing portion in the pressure resistant casing.

FIG. 41 is an explanatory view showing a housed state of the circuit unit in the pressure-resistant housing.

FIG. 42 is an explanatory view showing a heat radiation cushioning structure when the circuit unit is housed in the pressure resistant casing.

FIG. 43 is an explanatory diagram showing a state where the circuit unit housing is inserted into the pressure resistant housing.

FIG. 44 is an explanatory view showing a thermal equalization circuit model in the pressure resistant casing.

FIG. 45 is an explanatory view showing an example of a structure for conducting heat from a circuit unit to a circuit unit casing.

FIG. 46 is an explanatory diagram of heat induction to the pressure resistant casing.

FIG. 47 is a cross-sectional view showing the structure of an example of a cable retracting portion of a pressure-resistant housing.

FIG. 48 is an explanatory diagram showing a structure of an example of a gimbal portion of a pressure-resistant housing.

FIG. 49 is an explanatory view showing the structure of another example of the gimbal portion of the pressure-resistant housing.

FIG. 50 is an explanatory diagram showing the main specifications of the supervisory control in the present invention.

FIG. 51 is a block diagram showing an outline of the configuration of an example of a supervisory control system used in the type A system of the present invention.

FIG. 52 is an explanatory diagram showing an example of network monitoring control items in the monitoring control system.

FIG. 53 is a block diagram showing an example of a configuration of a supervisory control unit in the supervisory control system.

FIG. 54 is an explanatory diagram showing the functional division of the monitoring control unit.

FIG. 55 is an explanatory diagram showing a part of the functions of the monitoring control system.

FIG. 56 is an explanatory diagram showing a part of the functions of the above-mentioned monitoring control system.

FIG. 57 is an explanatory diagram showing a part of the functions of the monitoring control system.

FIG. 58 is an explanatory diagram showing a part of the functions of the above-mentioned monitoring control system.

FIG. 59 is an explanatory diagram showing an example of a frame configuration of a monitor control signal.

FIG. 60 is an explanatory diagram showing an example of an alarm transfer method in the supervisory control of the type A system of the present invention.

FIG. 61 is an explanatory diagram showing monitoring control items in the relay device used in the present invention.

FIG. 62 is an explanatory diagram showing a signal flow of a supervisory control system including a relay device according to the present invention.

FIG. 63 is a block diagram showing a supervisory control function of the relay device.

FIG. 64 is a block diagram showing a configuration of an example of a failure section evaluation device for a seabed A type system according to the present invention.

FIG. 65 is an explanatory diagram showing an example of a loopback method performed in the present invention.

FIG. 66 is a block diagram showing an outline of the configuration of an example of a supervisory control system used in the B-type system of the present invention.

67 is an explanatory diagram showing an example of network monitoring control items in the monitoring control system. FIG.

FIG. 68 is an explanatory diagram showing an example of an alarm transfer method in the supervisory control of the type A system of the present invention.

FIG. 69 is a block diagram showing the configuration of an example of a failure section evaluation device for a submarine B type system according to the present invention.

FIG. 70 is an explanatory diagram showing an example of a failure section evaluation function in the seabed B type system.

71 is an explanatory diagram showing OTDR specifications in the submarine B-type system. FIG.

[Explanation of symbols]

2 ... Submarine optical amplification repeater (repeater), 6, 8 ... Optical fiber cable, 10 ... Optical terminal device (LT-MUX), 2
4 ... Optical terminal station transmitter, 26 ... Optical terminal station receiver, 28 ... Intra-station interface, 32 ... Electric / optical converter, 34 ... Optical /
Electric conversion unit, 36 ... Monitoring control unit, 38 ... Timing supply unit, 40 ... Optical booster amplifier, 41, 43 ... Optical fiber amplifier, 42 ... Optical preamplifier, 44 ... Multiplexing circuit, 46
... Separation circuit, 56 ... Power supply section, 80 ... Modulator drive circuit, 8
2 ... Modulator integrated light source module, 84 ... Optical output control circuit, 86 ... Temperature control circuit, 98, 124, 310, 31
4 ... Er fiber, 100, 124 ... Wavelength multiplex WDM coupler, 94, 104, 106, 128 ... Excitation light source, 11
4 ... Monitoring light source, DA1, UA1 ... Low noise amplifier, DA
2, UA2 ... High output amplifier, RBU ... Loopback function, 400 ... Board, 402 ... Bobbin, 500 ... Circuit unit, 502 ... Pressure resistant housing, 522 ... Circuit unit housing,
530, 536 ... Leaf spring (heat conduction plate), 532 ... Rubber buffer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshihiro Yano, Inventor Yoshihiro Yano, 216 Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa, Ltd.Hitachi, Ltd., Information & Communication Division (72) Yoichi Igarashi, 216 Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa Hitachi Ltd., Information & Communication Division (72) Inventor Hironari Matsuda, 216 Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture Incorporated Information & Communications Division, Hitachi, Ltd. (72) Satoshi Aoki Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa 216 Incorporated company Hitachi, Ltd., Information & Communication Division (72) Inventor Yukio Nakano 1-280, Higashi Koikekubo, Kokubunji, Tokyo Metropolitan Research Laboratory, Hitachi, Ltd. (72) Masahiro Takatori 1-280, Higashi Koikeku, Kokubunji, Tokyo Central Research Laboratory, Hitachi, Ltd. (72) Inventor Toru Kazawa Tokyo 1-280, Higashi Koikekubo, Branch Temple City, Central Research Laboratory, Hitachi, Ltd. (72) Inventor: Shinya Sasaki 1-280, Higashi Koikeku, Hitachi Kokubunji City, Central Research Laboratory, Hitachi, Ltd. (72) Inventor, Ryoji Wuhou Higashi Koikeku, Kokubunji City, Tokyo 1-280-1 Hitachi Central Research Laboratory (72) Inventor Hiroyuki Nakano 1-280 Higashi-Kengikubo, Kokubunji-shi, Tokyo Inside Hitachi Central Research Laboratory

Claims (14)

[Claims] 1. A submarine high-speed optical transmission system in which optical terminal devices are connected by an optical fiber cable laid on the seabed to perform communication by optical transmission, wherein the optical terminal devices are a main signal light and a monitor. The transmitter has a transmitter that multiplexes and outputs the signal light, and the transmitter has an optical booster amplifier that optically amplifies the main signal light.
The main signal light is optically amplified by using pumping light of a wavelength different from that of the main signal light, and the monitoring signal light of the same wavelength as the pumping light is output to combine the main signal light and the monitoring signal light. A submarine high-speed optical transmission system characterized by having an output function. 2. The transmission according to claim 1, wherein at least one relay device is provided between the optical terminal stations, and the relay device multiplexes the main signal light and the supervisory signal light and outputs the multiplexed signal. And a transmitter having an optical booster amplifier for optically amplifying the main signal light, and the optical booster amplifier optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light. Along with the output of the monitoring signal light of the same wavelength as the pump light,
A submarine high-speed optical transmission system having a function of multiplexing and outputting main signal light and supervisory signal light. 3. The optical booster amplifier according to claim 1, wherein the optical booster amplifier optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light, and monitors the same wavelength as the pumping light. A submarine high-speed optical transmission system having a monitoring light source that outputs signal light, and a coupler that multiplexes the main signal light and the monitoring signal light. 4. The optical terminal station device according to claim 1, wherein at least one repeater device is provided between the optical terminal devices, and the repeater device receives the main signal light received from the preceding stage device at a wavelength different from that of the main signal light. A first amplifying section that optically amplifies the main signal light by using the pumping light, and a second amplifying section that further optically amplifies the amplified main signal light by using the pumping light having a wavelength different from that of the main signal light. The second amplification section optically amplifies the main signal light by using pumping light having a wavelength different from that of the main signal light, and outputs the supervisory signal light having the same wavelength as the pumping light to obtain the main signal light. A submarine high-speed optical transmission system having a function of multiplexing and outputting a monitoring signal light. 5. A submarine high-speed optical transmission system in which optical terminal cables are connected to each other by optical fiber cables laid on the seabed, and at least one relay is provided between the optical terminal stations. The apparatus is arranged, and the repeater includes a first amplification unit that optically amplifies the main signal light received from the preceding apparatus by using pumping light having a wavelength different from that of the main signal light, and the amplified main signal light. A submarine high-speed optical transmission system comprising: a second amplification unit that further amplifies the signal light by using pumping light having a wavelength different from that of the main signal light. 6. The method according to claim 4 or 5, wherein one set of a first amplification section and a second amplification section is provided for the downlink and the uplink, and the first amplification section and the second amplification section for the downlink and the uplink are provided. The loopback unit further includes a loopback unit connecting between the amplification unit and the loopback unit. The loopback unit includes an optical switch, and the optical switch allows normal transmission and one direction from upstream to downstream and downstream to upstream. A submarine high-speed optical transmission system having a configuration in which loopback can be switched. 7. The method according to claim 5, wherein at least one of the first amplification section and the second amplification section is provided with at least two light sources for generating pumping light, a working light source and a spare light source.
A submarine high-speed optical transmission system that uses two excitation light sources by switching them. 8. A submarine high-speed optical transmission system according to claim 7, further comprising means for separating the supervisory signal light sent from the preceding device, and switching the pumping light generation source according to an instruction of the supervisory signal. 9. The submarine high-speed optical transmission system according to claim 6, further comprising means for separating the supervisory signal light sent from the preceding stage device, and switching the loopback optical switch according to an instruction of the supervisory signal. 10. A submarine high-speed optical transmission system in which optical terminal devices are connected by an optical fiber cable laid on the seabed to perform communication by optical transmission, and at least one relay is provided between the optical terminal devices. The repeater is equipped with an optical amplifier that amplifies the main signal light received from the pre-stage device by using pumping light of a wavelength different from that of the main signal light, and the monitoring sent from the pre-stage device. A submarine high-speed optical transmission system comprising means for separating signals and means for changing the output of the pumping light of the optical amplifying section and changing the output level of the main signal light according to an instruction of the monitoring signal. . 11. The method according to claim 4, 8, 9 or 10.
A wavelength division multiplexing (WDM) coupler is provided as means for performing wavelength division multiplexing or demultiplexing of the main signal light and the supervisory signal light.
A submarine high-speed optical transmission system characterized by using a DM coupler as a wavelength multiplexing coupler for main signal light and pumping light. 12. A submarine high-speed optical transmission system in which optical terminal devices are connected by an optical fiber cable laid on the seabed to perform communication by optical transmission, and relays arranged on the seabed between the optical terminal devices. An apparatus, comprising: a plurality of circuit units having an optical amplification section for performing optical amplification; and a control section therefor, and a pressure-resistant housing having a cylindrical housing portion for housing the plurality of circuit units. The relay device is characterized in that three sets of circuit units are arranged in the pressure-resistant casing along the inner periphery of the pressure-resistant casing along each side of the triangle. 13. The optical amplifying unit according to claim 12, wherein the optical amplifying unit has one for upstream and the other for downstream, and each optical amplifying unit has first and second amplifying units each having an optical amplifying fiber. A repeater characterized in that the optical amplification fibers of the respective amplification units are wound on a common bobbin. 14. The relay device according to claim 13, wherein each circuit unit has two systems in one circuit unit.