JP6155803B2 - Optical wavelength division multiplexing communication system, optical wavelength division multiplexing communication method, and optical multiplexing / demultiplexing device - Google Patents

Description

  The present invention relates to an optical wavelength division multiplexing communication system, an optical wavelength division multiplexing communication method, and an optical multiplexing / demultiplexing device.

  In recent years, C-band (1530 nm to 1565 nm) or L band (1565 nm to 1625 nm) is mainly used in optical wavelength division multiplexing communication systems. These wavelength bands are defined by ITU-T (International Telecommunication Union Telecommunication Standardization Sector).

  In the optical wavelength division multiplexing communication system, the wavelength band that can be used is limited by the characteristics of the transmission path (for example, an optical fiber) and the optical device (for example, an optical amplifier, a laser diode, and a photodiode). Therefore, at present, it is mainly constructed by an optical wavelength division multiplexing communication system constructed by equipment (such as optical fibers and optical devices) capable of transmitting C-band optical signals and equipment capable of transmitting L-band optical signals. The optical wavelength division multiplexing communication system is in operation. For example, a silica-based optical fiber is used in a C-band optical wavelength multiplexing communication system, and a dispersion compensating fiber is used in an L-band optical wavelength multiplexing communication system. Based on the performance of such facilities, 1530 nm to 1560 nm are mainly used in the C-band optical wavelength division multiplexing communication system, and 1570 nm to 1610 nm are mainly used in the L band optical wavelength multiplexing communication system. .

  In particular, the C band is a global standard because it includes the lowest loss wavelength of silica-based optical fibers. That is, outside Japan, wavelength division multiplexing communication in the C band is realized. On the other hand, in Japan, a dispersion compensating fiber has been laid in a wide range, and therefore the zero dispersion wavelength (1550 nm) is considered in consideration of non-linear degradation due to four-wave mixing or the like that becomes prominent near the zero dispersion wavelength of the dispersion compensating fiber (1550 nm in the C band). ), And wavelength division multiplexing communication in the L band is realized.

  Here, in the optical wavelength division multiplexing communication, in order to realize a multi-channel, a high density of wavelength intervals is realized in a limited band. However, since the increase in density is limited by the modulation method or the like, it is required to increase the number of channels by increasing the bandwidth.

  Patent Document 1 discloses an optical transmission system that performs WDM (Wavelength Division Multiplexing) optical transmission over a wide band including S, C, and L bands. In this optical transmission system, the multiplexed signal light is first Raman-amplified by a distributed Raman amplifier, and then the multiplexed signal light is amplified by a lumped constant optical amplifier. As a result, the multiplexed signal light is Raman-amplified so that the power of the short-wavelength signal channel becomes higher, and then input to the lumped-constant optical amplifier. There is no need to make it large, and the variation in noise figure is improved.

JP 2004-78176 A

  As described above, the optical transmission system disclosed in Patent Document 1 achieves a wider bandwidth by performing WDM optical transmission in a wide band including the S, C, and L bands. However, in the technology disclosed in Patent Document 1, it is necessary to replace existing facilities (such as optical fiber and optical device) in the network with a device that supports a wide band including S, C, and L bands as a whole. There is a problem that it costs a lot of money.

  In order to solve the above-described problems, an object of the present invention is to provide an optical wavelength division multiplexing communication system, an optical wavelength division multiplexing communication method, and an optical multiplexing / demultiplexing apparatus capable of realizing a wide band while reducing costs. It is to be.

  The optical wavelength division multiplexing communication system according to the first aspect of the present invention is assigned to each of a plurality of wavelength bands, and converts an input electric signal into an optical signal of the assigned wavelength band and outputs the optical signal. A plurality of transmission side conversion units; a transmission side multiplexing unit that combines a plurality of optical signals output from the plurality of transmission side conversion units; and transmits the multiplexed signal as a wavelength multiplexed optical signal via the network; and A wavelength-division multiplexed optical signal transmitted from a wave unit via the network, a received-side demultiplexing unit that demultiplexes the received wavelength-multiplexed optical signal into the plurality of optical signals, and outputs the plurality of wavelength bands; And a plurality of receiving side conversion units that convert optical signals in the assigned wavelength band among the plurality of optical signals output from the receiving side demultiplexing unit to electrical signals. The plurality of wavelength bands are small Both and a wavelength band including a part of the wavelength band and L-band including a portion of the C-band, it does not include the wavelength band including a non-C-band and L-band, is intended.

  An optical wavelength division multiplexing communication method according to a second aspect of the present invention includes a step of converting each of a plurality of electrical signals into a plurality of optical signals that are respectively in a plurality of wavelength bands, and the plurality of optical signals. Multiplexing and transmitting as a wavelength multiplexed optical signal via a network; receiving the transmitted wavelength multiplexed optical signal via the network; and demultiplexing the received wavelength multiplexed optical signal into the plurality of optical signals And converting each of the plurality of demultiplexed wavelength bands into each of the plurality of electric signals, wherein the plurality of wavelength bands include at least a part of the C band. And a wavelength band including a part of the L band, and does not include a wavelength band including other than the C band and the L band.

  The optical multiplexing / demultiplexing device according to the third aspect of the present invention receives each of a plurality of optical signals in a plurality of wavelength bands from each of a plurality of electro-optical converters that convert an electric signal into an optical signal. 1 receiving unit, a plurality of optical signals received by the first receiving unit are combined to generate a wavelength multiplexed optical signal, and the wavelength multiplexed optical signal generated by the combining unit is connected to the network. A first transmitter for transmitting via the network, a second receiver for receiving, via the network, a wavelength-multiplexed optical signal obtained by combining a plurality of optical signals of the plurality of wavelength bands, and the second The demultiplexing unit that demultiplexes the wavelength-multiplexed optical signal received by the receiving unit, generates the plurality of optical signals, and converts each of the plurality of optical signals generated by the demultiplexing unit into an optical signal. A second transmitter for transmitting to a plurality of photoelectric converters to be converted Wherein the plurality of wavelength bands includes a wavelength band including a part of the wavelength band and L band including at least a portion of the C-band, it does not include the wavelength band including a non-C-band and L-band, is intended.

  According to each aspect of the present invention described above, it is possible to provide an optical wavelength division multiplexing communication system, an optical wavelength division multiplexing communication method, and an optical multiplexing / demultiplexing device that can realize a wide band while reducing costs.

1 is a configuration diagram of an optical wavelength division multiplexing communication system according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating a wavelength band of a wavelength multiplexed optical signal according to the first embodiment. FIG. 5 is another configuration diagram of the optical wavelength division multiplexing communication system according to the first embodiment. 6 is a diagram illustrating a wavelength band of a wavelength multiplexed optical signal according to Embodiment 2. FIG. FIG. 6 is a configuration diagram of a wavelength division multiplexing optical signal conversion system according to a third embodiment. FIG. 10 is a diagram illustrating conversion wavelength bands of wavelength-multiplexed optical signals before and after conversion according to Embodiment 3. FIG. 10 is another configuration diagram of the wavelength division multiplexing optical signal conversion system according to the third embodiment. FIG. 6 is a configuration diagram of a wavelength division multiplexing optical signal conversion system according to a fourth embodiment. It is a figure which shows the conversion wavelength band of the wavelength multiplexing optical signal before and behind the conversion which concerns on Embodiment 4. FIG. FIG. 10 is another configuration diagram of the wavelength division multiplexing optical signal conversion system according to the fourth embodiment. It is a schematic block diagram of the optical wavelength division multiplexing communication system which concerns on embodiment.

<Embodiment 1 of the Invention>
First, the first embodiment of the present invention will be described. With reference to FIG. 1, the configuration of an optical wavelength division multiplexing communication system 1 according to Embodiment 1 of the present invention will be described. FIG. 1 is a configuration diagram of an optical wavelength division multiplexing communication system 1 according to Embodiment 1 of the present invention.

  The optical wavelength division multiplexing communication system 1 includes transmission processing systems 10-1 to 10-N, reception processing systems 11-1 to 11-N, and E / O converters (electric / optical converters) 20-1 to 20-. N, O / E converters 21-1 to 21 -N, an optical multiplexer 30, an optical demultiplexer 31, an optical amplifier 40, and optical fibers 50 and 51.

  Hereinafter, each of the transmission side processing systems 10-1 to 10-N is also collectively referred to as “transmission side processing system 10”, and each of the reception side processing systems 11-1 to 11-N is generally referred to as “reception side processing system 11”. The E / O converters 20-1 to 20-N are also collectively referred to as “E / O converters 20”, and the O / E converters 21-1 to 21-N are generally referred to as “ Also referred to as “O / E converter 21”.

  Here, “N” is an arbitrary positive integer determined in advance. That is, in the first embodiment, the optical wavelength division multiplexing communication system 1 has an example in which each of the transmission side processing system 10, the reception side processing system 11, the E / O converter 20, and the O / E converter 21 has N pieces. Show. Hereinafter, “k” corresponds to any of 1 to N.

  The transmission side processing system 10-k is a device that transmits data to the reception side processing system 11-k. When transmitting data to the receiving side processing system 11-k, the transmitting side processing system 10-k transmits an electrical signal indicating the data to the E / O converter 20-k. In the present embodiment, an example in which the transmission processing system 10 is an information processing apparatus will be described. The information processing apparatus may be any apparatus as long as it is connected to a part of a network (for example, the Internet) constructed by optical wavelength division multiplexing communication and transmits / receives arbitrary data. For example, the transmission processing system 10 is a personal computer.

  The reception side processing system 11-k is a device that receives data from the transmission side processing system 10-k. The reception side processing system 11-k receives an electrical signal indicating the data from the O / E converter 21-k as data from the transmission side processing system 10-k. In the present embodiment, an example in which the reception-side processing system 11 is a higher-level device of an OLT (Optical Line Terminal) described later will be described. For example, the reception processing system 11 is a layer 2 switch. Therefore, in FIG. 1, the receiving side processing systems 11-1 to 11-N are illustrated separately, but they may all be the same device (layer 2 switch).

  The E / O converter 20-k receives the electrical signal transmitted from the transmission side processing system 10-k, and converts the received electrical signal into an optical signal. The E / O converter 20-k includes a laser diode (LD) 200-k. The E / O converter 20-k generates an optical signal in the wavelength band λ (k) by causing the LD 200-k to oscillate light in a predetermined wavelength band λ (k) as an optical signal after conversion. To do. The E / O converter 20-k transmits the converted optical signal to the optical multiplexing device 30. The optical signal generated by each of the E / O converters 20-1 to 20-N is an optical signal per channel. The E / O converter 20 is, for example, an ONU (Optical Network Unit).

  The O / E converter 21-k receives the optical signal in the wavelength band λ (k) transmitted from the optical demultiplexing device 31, and converts the received optical signal into an electrical signal. The O / E converter 21-k includes a photodiode (PD) 210-k. The O / E converter 21-k generates an electrical signal by receiving an optical signal in the wavelength band λ (k) by the PD 210-k as the converted electrical signal. The O / E converter 21-k transmits the converted electrical signal to the reception processing system 11-k. The O / E converter 21 is, for example, an OSU (Optical Subscriber Unit). That is, an OLT (operator side termination device) is configured including the O / E converters 21-1 to 21-N.

  The optical multiplexer 30 receives the optical signals transmitted from the E / O converters 20-1 to 20-N, multiplexes the received optical signals, and generates a wavelength multiplexed optical signal. As a result, a wavelength-multiplexed optical signal in which N-channel optical signals are multiplexed is generated. The optical multiplexer 30 transmits the generated wavelength multiplexed optical signal to the optical demultiplexer 31 via the optical fiber 50.

  The optical demultiplexing device 31 receives the wavelength multiplexed optical signal transmitted from the optical multiplexing device 30, and demultiplexes the received wavelength multiplexed optical signal into optical signals in the wavelength bands λ (1) to λ (N). To do. That is, the wavelength multiplexed optical signal is demultiplexed into optical signals for each channel. The optical demultiplexer 31 transmits an optical signal in the wavelength band λ (k) generated by demultiplexing to the O / E converter 21-k. As a result, the optical signal generated by the E / O converter 20-k is received by the O / E / O converter 21-k.

  As shown in FIG. 1, when a wavelength multiplexed optical signal is transmitted through optical fibers 50 and 51 having two or more spans, the wavelength multiplexed optical signal is amplified by an optical amplifier 40. The optical amplifier 40 receives the wavelength multiplexed optical signal transmitted from the optical multiplexer 30 via the optical fiber 50 and amplifies the received wavelength multiplexed optical signal. The optical amplifier 40 transmits the amplified wavelength multiplexed optical signal to the optical demultiplexing device 31 via the optical fiber 51. The optical amplifier 40 is, for example, an EDFA (Erbium Doped Optical Fiber Amplifier) or an EDTFA (Erbium Doped Tellurite Fiber Amplifier: ER3 + -added tellurite fiber amplifier).

  In FIG. 1, for simplification of explanation, only the optical fibers 50 and 51 for two spans are illustrated as a network (transmission path) between the optical multiplexing device 30 and the optical demultiplexing device 31. The number is not limited to this. The optical fibers 50 and 51 are, for example, a dispersion compensating optical fiber or a quartz optical fiber. The optical fibers 50 and 51 are, for example, single mode optical fibers.

  As described above, the optical wavelength division multiplexing communication system 1 according to the present embodiment includes the existing C-band optical wavelength division multiplexing communication system equipment (such as an optical fiber and an optical device) and the existing L-band optical wavelength division multiplexing communication. A network for transmitting wavelength-multiplexed optical signals is configured including the equipment in which the system is installed (for example, optical fibers 50 and 51 and optical amplifier 40).

  These existing facilities actually have the ability to process optical signals beyond the operating wavelength band as long as they are in the C band and L band wavelength bands and up to a certain wavelength band. Yes. Therefore, the optical wavelength division multiplexing communication system 1 according to the present embodiment realizes a wide band while diverting existing equipment for the C band and the L band. Next, with reference to FIG. 2, the realization method is demonstrated concretely.

  Next, with reference to FIG. 2, the wavelength band of the wavelength multiplexed optical signal according to Embodiment 1 of the present invention will be described. FIG. 2 is a diagram showing wavelength bands of wavelength-multiplexed optical signals according to Embodiment 1 of the present invention.

  As shown in FIG. 2, for example, 1530 nm to 1560 nm are mainly used in the C-band optical wavelength division multiplexing communication system due to limitations on the optical amplification band of the optical amplifier, and 1570 nm in the L-band optical wavelength multiplexing communication system. To 1610 nm are used.

  On the other hand, the wavelength band (wavelength band of the wavelength multiplexed optical signal) used in the optical wavelength division multiplexing communication system 1 includes a wavelength of 1565 nm serving as a boundary between the C band and the L band, and C continuously from the wavelength serving as the boundary. A wavelength band including at least a part of both the band and the L band is used. Therefore, each of the wavelength bands λ (1) to λ (N) of the optical signal generated by the E / O converters 20-1 to 20-N is the wavelength used in the optical wavelength division multiplexing communication system 1 as described above. Each of the wavelength bands obtained by continuously dividing the wavelength band determined as the band into N is obtained.

  The upper and lower limits of the wavelength band of the wavelength multiplexed optical signal indicate that the wavelength multiplexed optical signal is normal depending on the performance of the devices (such as the optical fibers 50 and 51 and the optical amplifier 40) included in the network and the transmission distance of the network. What is necessary is just to determine arbitrarily so that it may become the range which can be transmitted. Therefore, if allowed by the network, the wavelength band of the wavelength multiplexed optical signal may be determined as all wavelength bands of the C band and the L band.

  In addition, the transmission side processing systems 10-1 to 10-N, the reception side processing systems 11-1 to 11-N, the optical multiplexing device 30, and the optical demultiplexing device 31 have the determined wavelength bands (wavelengths) of wavelength multiplexed optical signals. There is a possibility that a device corresponding to the bands λ (1) to λ (N)) is newly installed. In some cases, the optical amplifier 40 is not limited to the diverted one, and a part of the optical amplifier 40 may be replaced with one that can amplify the optical amplification band suitable for the wavelength band used in the optical wavelength division multiplexing communication system 1. For this reason, the upper and lower limits of the wavelength band of the wavelength multiplexed optical signal may be determined so as to be an acceptable cost in consideration of the cost for installing these facilities.

  However, when a dispersion compensating optical fiber is included in the optical fibers 50 and 51 of the network, since the zero dispersion wavelength (1550 nm) is included, nonlinear degradation occurs in the optical signal. Therefore, when determining the wavelength band to be used so as to include this wavelength, this is preferably used as an optical wavelength division multiplexing communication system for short-distance transmission (several meters to several hundreds of meters). However, many non-zero dispersion shifted optical fibers in which the zero dispersion wavelength is shifted to the shorter wavelength side than the C band are also laid as dispersion compensating optical fibers. Therefore, in the case of constructing the optical wavelength division multiplexing communication system 1 in a network including only non-zero dispersion shifted optical fibers as dispersion compensating optical fibers, optical wavelength multiplexing for not only short-distance transmission but also longer-distance transmission is used. It may be used as a communication system.

  As described above, according to the first embodiment, it is possible to use the wavelength band optimized for the characteristics of the transmission path and the optical device to be used without depending on the division of the C band and the L band. More efficient optical multiplex communication can be realized. That is, the wavelength band used in this embodiment is a wavelength range (1530 nm to 1565 nm) used in an optical wavelength division multiplexing communication system using only the C band and a wavelength used in an optical wavelength multiplexing communication system using only the L band. Compared with the range (1565 nm to 1610 nm), since both the C-band and L-band wavelength ranges are used, a wider band can be realized.

  Further, the first embodiment can be realized by adding simple modifications to the existing optical wavelength division multiplexing communication system using only the L band and the optical wavelength multiplexing communication system using only the C band. That is, as described above, existing equipment (such as an optical fiber and an optical amplifier) can be used and can be easily realized. Therefore, the cost can be greatly reduced in the realization of the optical wavelength division multiplexing communication system. This eliminates the need to replace a large amount of various devices (such as optical fibers and optical amplifiers) in a wide range of optical wavelength division multiplexing communication networks, and thus has a significant cost reduction effect.

  Here, as described above, in the environment where the dispersion compensating optical fiber is laid, there is a concern about nonlinear deterioration due to four-wave mixing that becomes noticeable near the zero dispersion wavelength (1550 nm), and the zero dispersion wavelength (1550 nm) is not included. An L-band optical multiplex communication system is realized. In the L band, when a light receiving element (photodiode) using indium gallium arsenide is used, it is difficult to realize high quantum efficiency on the long wavelength side. Further, when a light receiving element made of another compound semiconductor is used, there is a high possibility that the cost will be high. Furthermore, especially on the long wavelength side of 1610 nm or more, an increase in transmission loss due to Rayleigh scattering and a small decrease in the amount of dispersion compensation can be mentioned.

  From these, good optical characteristics can be obtained without depending on the transmission path and optical device, in the range of 1550 nm or more which is the zero dispersion wavelength of the dispersion compensating optical fiber and 1610 nm or less not including the long wave side of the L band ( 1560 nm to 1610 nm). However, the wavelength band from 1560 nm to 1570 nm is not generally used because it is an intermediate region between the C band and the L band. On the other hand, in the present embodiment, since a continuous wavelength band including a wavelength band from 1560 nm to 1570 nm is used around a wavelength of 1565 nm, which is a boundary between the C band and the L band, good optical performance is obtained. Wide band is realized while obtaining the characteristics.

  In the above description, for simplification of description, an example in which an optical signal is transmitted from the transmission side processing systems 10-1 to 10-N to the reception side processing systems 11-1 to 11-N has been described. Of course, the optical signal may be transmitted from the reception side processing systems 11-1 to 11-N to the transmission side processing systems 10-1 to 10-N. That is, as shown in FIG. 3, the transmission processing systems 10-1 to 10-N may operate as reception processing systems, and the reception processing systems 11-1 to 11-N serve as transmission processing systems. It may work.

  Therefore, as shown in FIG. 3, the E / O converters 20-1 to 20-N may also operate as O / E converters, and the O / E converters 21-1 to 21-N are also It may operate as a / O converter. Similarly, the optical multiplexing device 30 may operate as an optical demultiplexing device, and the optical demultiplexing device 31 may operate as an optical multiplexing device. That is, as shown in FIG. 3, the optical multiplexing device 30 and the optical demultiplexing device 31 may operate as an optical multiplexing / demultiplexing device. The optical multiplexer / demultiplexer is, for example, an optical splitter (optical coupler).

  According to this, it operates as follows. The reception-side processing system 11-k (also serving as a transmission processing system) transmits an electrical signal indicating data to the O / E converter 21-k (also serving as an E / O converter). The O / E converter 21-k converts the electrical signal transmitted from the reception side processing system 11-k into an optical signal in the wavelength band λ (k) by the LD 211-k and transmits the optical signal to the optical demultiplexing device 31. . The optical demultiplexing device 31 (also serving as an optical multiplexing device) multiplexes the optical signals transmitted from the O / E converters 21-1 to 21-N, and converts the wavelength multiplexed optical signal into the optical fibers 52, 53 and The signal is transmitted to the optical multiplexer 30 via the optical amplifier 41. The optical fibers 52 and 53 and the optical amplifier 41 are the same as the optical fibers 50 and 51 and the optical amplifier 40. However, the optical fibers 52 and 53 and the optical amplifier 41 are targeted for wavelength multiplexed optical signals transmitted from the optical demultiplexing device 31 toward the optical multiplexing device 30.

  The optical multiplexing device 30 (also serving as an optical demultiplexing device) converts the wavelength multiplexed optical signal transmitted from the optical demultiplexing device 31 through the optical fibers 52 and 53 and the optical amplifier 41 into wavelength bands λ (1) to λ ( N) is demultiplexed into each optical signal and transmitted to each of the E / O converters 20-1 to 20-N. The E / O converter 20-k (also serving as the O / E converter) converts the optical signal in the wavelength band λ (k) transmitted from the optical multiplexing device 30 into an electrical signal by the PD 201-k, and transmits it to the transmission side. The data is transmitted to the processing system 10-k (also serving as the receiving side processing system).

<Embodiment 2 of the Invention>
Next, a second embodiment of the present invention will be described. Since the configuration of the optical wavelength division multiplexing communication system according to the second embodiment is the same as that of the first embodiment, description thereof is omitted. The wavelength band (wavelength band of the wavelength multiplexed optical signal) used in the optical wavelength division multiplexing communication system 1 according to the second embodiment is different from that of the first embodiment.

  Next, with reference to FIG. 4, the wavelength band of the wavelength multiplexed optical signal according to the second embodiment of the present invention will be described. FIG. 4 is a diagram showing wavelength bands of wavelength-multiplexed optical signals according to Embodiment 2 of the present invention.

  In the optical wavelength division multiplexing communication system 1 according to the second embodiment, a wavelength band from 1560 nm to 1610 nm is used. That is, the wavelength band of the wavelength multiplexed optical signal transmitted in the optical wavelength division multiplexing communication system 1 is a wavelength band from 1560 nm to 1610 nm. This wavelength band generally has sufficient optical characteristics for optical transmission, and is a wavelength band that does not depend on existing optical fibers and optical devices. Therefore, each of the wavelength bands λ (1) to λ (N) of the optical signal generated by the E / O converters 20-1 to 20-N is continuously divided into N wavelengths from 1560 nm to 1610 nm. For each of the selected wavelength bands.

  As described above, the second embodiment has sufficient optical characteristics for optical transmission and uses a wavelength band from 1560 nm to 1610 nm, and thus does not depend on optical fibers and optical devices. A network capable of long-distance transmission can be configured. In other words, in an optical wavelength division multiplexing communication system using only the existing C band and an optical wavelength multiplexing communication system using only the L band, it is naturally possible to transmit only an optical signal having a good optical characteristic. Therefore, there is no need to adjust the wavelength band in accordance with the performance of the existing system equipment (optical fiber, optical device, etc.), and a wider band can be realized more easily and at low cost.

  Also, depending on the wavelength band used in the second embodiment, compared with the wavelength range (1530 nm to 1560 nm) used in the optical wavelength division multiplexing communication system using only the C band, the optical wavelength using only the L band is 20 nm. Compared to the wavelength range (1570 nm to 1610 nm) used in the multiplex communication system, a wide band of 10 nm can be realized. In addition, the wavelength band may be expanded both on the long wavelength side and on the short wavelength side in accordance with changes in the performance of optical fibers and optical devices in the future.

  Note that the optical amplifier 40 may be changed from 1560 nm to 1610 nm as required, but even if the optical amplifier 40 is changed, the entire wavelength band of the C band and the L band is used. Compared with the case of using the narrow bandwidth, the cost of the optical amplifier 40 is reduced.

<Third Embodiment of the Invention>
Subsequently, Embodiment 3 of the present invention will be described. In addition to the various apparatuses 10, 11, 20, 21, 30, 31, 40, 50, 51 shown in FIG. 1, the optical wavelength division multiplexing communication system according to the third embodiment further includes the wavelength multiplexed light shown in FIG. A signal conversion system 2 is included. In addition, description is abbreviate | omitted about the apparatus 10,11,20,21,30,31,40,50,51 which becomes the component similar to FIG. 1, and demonstrates the wavelength division multiplexing optical signal conversion system 2. FIG. The wavelength band used in the optical wavelength division multiplexing communication system 1 according to the third embodiment (the wavelength band of the wavelength division multiplexing optical signal) is the same as the wavelength band used in the optical wavelength division multiplexing communication system 1 according to the second embodiment. It becomes.

  Subsequently, the configuration of the wavelength division multiplexing optical signal conversion system 2 according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram of the wavelength division multiplexing optical signal conversion system 2 according to Embodiment 3 of the present invention.

  The wavelength division multiplexing optical signal conversion system 2 includes an optical demultiplexing device 32, an optical multiplexing device 33, and wavelength conversion devices 60-1 to 60-N. The wavelength division multiplexing optical signal conversion system 2 converts the wavelength of the wavelength division multiplexed optical signal used in the L-band optical wavelength division multiplexing communication system into the wavelength division multiplexing used in the optical wavelength division multiplexing communication system 1 according to Embodiment 3 of the present invention. Convert to wavelength of optical signal.

  Hereinafter, each of the wavelength conversion devices 60-1 to 60-M is also collectively referred to as “wavelength conversion device 60”. Here, “M” is a predetermined positive integer. That is, the third embodiment shows an example in which the optical wavelength division multiplexing communication system 1 has M wavelength conversion devices 60. Hereinafter, “k” corresponds to any of 1 to M.

  The optical demultiplexing device 32 receives the wavelength multiplexed optical signal transmitted from the L-band optical wavelength multiplexing communication system to the optical wavelength multiplexing communication system according to the third embodiment, and receives the received wavelength multiplexed optical signal, The optical signals in the wavelength bands λ (1) to λ (M) and the optical signals in other wavelength bands are demultiplexed. As a result, the wavelength multiplexed optical signal includes an optical signal in a wavelength band that is not subject to wavelength conversion and an optical signal in the wavelength band that is subject to wavelength conversion (respective optical signals in the wavelength bands λ (1) to λ (M)). Generated. The optical demultiplexing device 32 transmits an optical signal in a wavelength band that is not subject to wavelength conversion among optical signals generated by demultiplexing to the optical multiplexing device 33, and an optical signal in the wavelength band that is subject to wavelength conversion (wavelength band λ ( 1) to λ (M)) are transmitted to the wavelength converters 60-1 to 60-M. The optical signal in the wavelength band λ (k) is transmitted to the wavelength conversion device 60-k.

  The optical multiplexing device 33 transmits an optical signal in a wavelength band not subject to wavelength conversion transmitted from the optical demultiplexing device 32 and an optical signal after wavelength conversion transmitted from each of the wavelength conversion devices 60-1 to 60-M ( Wavelength bands λ ′ (1) to λ ′ (M)) are combined to generate a wavelength multiplexed optical signal. The optical multiplexer 33 transmits the generated wavelength multiplexed optical signal toward the network in the optical wavelength multiplexing communication system 1 according to the third embodiment. As a result, the wavelength multiplexed optical signals transmitted toward the network in the optical wavelength division multiplexing communication system 1 are transmitted on the transmission side processing systems 10-1 to 10-N or the reception side processing systems 11-1 to 11-, for example. To N or the like.

  The wavelength conversion device 60-k converts the wavelength of the optical signal in the wavelength band λ (k) transmitted from the optical demultiplexing device 32, and generates an optical signal in the wavelength band λ ′ (k). The wavelength conversion device 60-k transmits the generated optical signal in the wavelength band λ ′ (k) to the optical multiplexing device 33.

  Next, with reference to FIG. 6, the conversion wavelength band of the wavelength multiplexed optical signal according to Embodiment 3 of the present invention will be described. FIG. 6 is a diagram showing a converted wavelength band of a wavelength multiplexed optical signal according to Embodiment 3 of the present invention.

  In the third embodiment, a longer wave than 1610 nm is used in the L-band optical wavelength multiplex communication system, and transmission near 1610 nm is performed due to the limitation of the optical device of the optical multiplex communication system 1 according to the third embodiment. If this is difficult, the problem can be solved by converting the wavelength band of the wavelength multiplexed optical signal as shown in FIG. As shown in FIG. 6, in the wavelength division multiplexing optical signal conversion system 2 according to Embodiment 3 of the present invention, only the optical signal near 1610 nm is demultiplexed and the wavelength is converted. As a result, the optical signal of each channel on the longer wavelength side than 1610 nm in the L band is converted from an optical signal of 1560 nm to 1570 nm in the optical multiplex communication system 1 according to the third embodiment.

  For example, as shown in FIG. 6, it is assumed that an L-band optical wavelength division multiplexing communication system uses 1570 nm to 1620 nm. In this case, in order to convert the L-band wavelength multiplexed optical signal to the wavelength band (1560 nm to 1610 nm) of the optical multiplexing communication system 1 according to Embodiment 3, it is necessary to convert the wavelength band from 1570 nm to 1610 nm. Rather, it can be realized by converting the wavelength band from 1610 nm to 1620 nm into the wavelength band from 1560 nm to 1570 nm. Therefore, each of the wavelength bands λ (1) to λ (M) of the above-described optical signal to be converted is a wavelength band obtained by continuously dividing the wavelength band from 1610 nm to 1620 nm into M. Further, the wavelength bands λ ′ (1) to λ ′ (M) of the optical signal after wavelength conversion described above are the wavelength bands obtained by continuously dividing the wavelength band from 1560 nm to 1570 nm into M. Thus, the optical signal in the wavelength conversion target wavelength band is demultiplexed into M optical signals for each channel.

  In this case, the wavelength band width before and after the conversion is both 10 nm, but it can be realized even when the wavelength band width is different before and after the conversion by adjusting the channel interval. For example, the wavelength band of the L-band wavelength multiplexed optical signal is 1570 nm to 1630 nm (exceeding 1625 nm, but for convenience of explanation), and 10 in a wavelength band of 20 nm width (1610 nm to 1630 nm) to be converted. When channels exist, the same number of 10 channels can be accommodated in the converted wavelength band (1560 nm to 1570 nm) by halving the wavelength band width per channel after conversion. Note that the delay caused by the wavelength converter may be compensated by a general method using a chromatic dispersion compensator, and thus detailed description thereof is omitted.

  As described above, according to the third embodiment, by incorporating a simple system such as the wavelength division multiplexing optical signal conversion system 2, the existing L-band optical wavelength division multiplexing communication system and the present embodiment Communication with the three optical wavelength division multiplexing communication systems 1 can be realized. Further, in the third embodiment, the wavelength band from 1570 nm to 1610 nm can be used without conversion as compared with the case of converting from the L-band optical wavelength multiplexing communication system to the C-band optical wavelength multiplexing communication system. Significant power savings can be expected. In addition, since an optical signal is transmitted in a wavelength band with good optical characteristics, communication in a more efficient wavelength band becomes possible.

  In the above description, for simplification of description, an example in which an optical signal is transmitted from the L-band optical wavelength division multiplexing communication system to the optical wavelength division multiplexing communication system 1 according to the third embodiment has been described. The optical signal may be transmitted from the optical wavelength division multiplexing communication system 1 according to the third embodiment to the L-band optical wavelength division multiplexing communication system. That is, the wavelength division multiplexing optical signal conversion system 2 may further include an optical multiplexing device 34, an optical demultiplexing device 35, and wavelength conversion devices 61-1 to 61-M, as shown in FIG. The wavelength conversion of the wavelength multiplexed optical signal by these devices is the same except that the conversion is the reverse of the conversion described above, so only a brief description will be given below.

  For example, the wavelength band used by the optical wavelength division multiplexing communication system in the L band and the wavelength band used by the optical wavelength division multiplexing communication system 1 according to the third embodiment are the same wavelength bands (1570 nm to 1620 nm and 1560 nm as described above). (1616 nm). In this case, the optical demultiplexing device 35 receives the wavelength division multiplexed optical signal transmitted from the optical wavelength division multiplexing communication system 1 according to the present embodiment to the L-band optical wavelength division multiplexing communication system, and receives the received wavelength division multiplexed light. The signal is demultiplexed into optical signals (wavelength conversion targets) in the wavelength bands λ ′ (1) to λ ′ (M) and optical signals in other wavelength bands (not wavelength conversion targets). The optical demultiplexing device 35 transmits an optical signal in a wavelength band that is not subject to wavelength conversion among optical signals generated by demultiplexing to the optical multiplexing device 34, and an optical signal in the wavelength band that is subject to wavelength conversion (wavelength band λ ′). (1) to λ ′ (M) optical signals) are transmitted to the wavelength converters 61-1 to 61-M. The wavelength conversion device 60-k converts the optical signal in the wavelength band λ (k) ′ transmitted from the optical demultiplexing device 35 into an optical signal in the wavelength band λ (k), and transmits the optical signal to the optical multiplexing device 34. The optical multiplexing device 34 includes an optical signal in a wavelength band not subject to wavelength conversion transmitted from the optical demultiplexing device 35 and an optical signal after wavelength conversion transmitted from each of the wavelength conversion devices 61-1 to 61-M ( Wavelength bands λ (1) to λ (M)) are multiplexed to generate a wavelength multiplexed optical signal, which is transmitted to the L band optical wavelength multiplexing communication system.

  The optical multiplexing device 34, the optical demultiplexing device 35, and the wavelength conversion devices 61-1 to 61-M are respectively the optical demultiplexing device 32, the optical multiplexing device 33, and the wavelength conversion devices 60-1 to 60-M. These may be configured as the same device.

<Embodiment 4 of the Invention>
Next, a fourth embodiment of the present invention will be described. In addition to the various apparatuses 10, 11, 20, 21, 30, 31, 40, 50, 51 shown in FIG. 1, the optical wavelength division multiplexing communication system according to the third embodiment further includes the wavelength multiplexed light shown in FIG. A signal conversion system 3 is included. In addition, description is abbreviate | omitted about the apparatus 10,11,20,21,30,31,40,50,51 used as the component similar to FIG. 1, and the wavelength multiplexing optical signal conversion system 3 is demonstrated. Further, the wavelength band (wavelength band of the wavelength multiplexed optical signal) used in the optical wavelength division multiplexing communication system 1 according to the fourth embodiment is the same as the wavelength band used in the optical wavelength multiplexing communication system 1 according to the second embodiment. It becomes.

  Next, the configuration of the wavelength division multiplexing optical signal conversion system 3 according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 8 is a configuration diagram of the wavelength division multiplexing optical signal conversion system 3 according to Embodiment 4 of the present invention.

  The wavelength division multiplexing optical signal conversion system 3 includes an optical demultiplexing device 36, an optical multiplexing device 37, and wavelength conversion devices 62-1 to 62-N. The wavelength division multiplexing optical signal conversion system 3 transmits the wavelength of the wavelength division multiplexed optical signal (1530 nm to 1560 nm) transmitted in the C-band optical wavelength division multiplexing communication system in the optical wavelength division multiplexing communication system 1 according to the fourth embodiment. The wavelength is converted to the wavelength of the wavelength multiplexed optical signal (1560 nm to 1610 nm).

  The operations of the optical demultiplexing device 36, the optical multiplexing device 37, and the wavelength conversion devices 62-1 to 62-N are the same as those of the optical demultiplexing device 32, the optical multiplexing, except that the wavelength band is different from that of the third embodiment. Since it is the same as that of the wave apparatus 33 and the wavelength converters 60-1 to 60-N, detailed description is abbreviate | omitted.

  Next, with reference to FIG. 9, a conversion wavelength band of the wavelength multiplexed optical signal according to Embodiment 4 of the present invention will be described. FIG. 9 is a diagram showing a converted wavelength band of a wavelength multiplexed optical signal according to Embodiment 4 of the present invention.

  As shown in FIG. 9, in the wavelength division multiplexing optical signal conversion system 3 according to Embodiment 4 of the present invention, an optical signal of a channel shorter than 1560 nm in the C band is used as an optical multiplexing communication system according to this embodiment. In 1570 nm to 1610 nm.

  For example, as shown in FIG. 9, it is assumed that a C-band optical wavelength division multiplexing communication system uses 1530 nm to 1565 nm. In this case, in order to convert the C-band wavelength multiplexed optical signal to the wavelength band (1560 nm to 1610 nm) of the optical multiplexing communication system 1 according to the present embodiment, it is necessary to convert the wavelength band from 1560 nm to 1565 nm. Instead, it can be realized by converting the wavelength band from 1530 nm to 1560 nm into the wavelength band from 1570 nm to 1610 nm. Therefore, each wavelength band λ (1) to λ (M) of the above-described optical signal to be converted is a wavelength band obtained by continuously dividing the wavelength band from 1530 nm to 1560 nm into M. In addition, each of the wavelength bands λ ′ (1) to λ ′ (M) of the optical signal after wavelength conversion described above is a continuous wavelength band having a predetermined width of 30 nm among wavelength bands from 1570 nm to 1610 nm. Thus, each wavelength band is divided into M. Thus, the optical signal in the wavelength conversion target wavelength band is demultiplexed into M optical signals for each channel.

  In this case, the wavelength band width before and after the conversion is both 30 nm, but it can be realized even when the wavelength band width is different before and after the conversion by adjusting the channel interval, as in the third embodiment. For example, if there are 10 channels in the wavelength band of 30 nm width (1530 nm to 1560 nm) to be converted, the wavelength band width per channel after conversion is increased to 4/3 times to obtain 40 nm after conversion. The same number of 10 channels can be accommodated in the wavelength band of the width (1570 nm to 1610 nm). Note that the delay caused by the wavelength converter may be compensated by a general method using a chromatic dispersion compensator, and thus detailed description thereof is omitted.

  As described above, according to the fourth embodiment, by incorporating a simple system such as the wavelength division multiplexing optical signal conversion system 3, the existing C-band optical wavelength division multiplexing communication system and the present embodiment Communication with the optical wavelength division multiplexing communication system 1 can be realized. In the fourth embodiment, the wavelength band from 1560 nm to 1565 nm can be used without conversion, as compared with the case of converting from the C-band optical wavelength multiplexing communication system to the L-band optical wavelength multiplexing communication system. Power saving can be expected. In addition, since an optical signal is transmitted in a wavelength band with good optical characteristics, communication in a more efficient wavelength band becomes possible.

  In the above description, for the sake of simplification, an example in which an optical signal is transmitted from the C-band optical wavelength division multiplexing communication system to the optical wavelength division multiplexing communication system 1 according to the present embodiment has been described. The optical signal may be transmitted from the optical wavelength division multiplexing communication system 1 according to the embodiment to the C-band optical wavelength division multiplexing communication system. That is, the wavelength division multiplexing optical signal conversion system 3 may further include an optical multiplexing device 38, an optical demultiplexing device 39, and wavelength conversion devices 63-1 to 63-M, as shown in FIG. The operations of the optical multiplexing device 38, the optical demultiplexing device 39, and the wavelength conversion devices 63-1 to 63-M are the same as those of the optical multiplexing device 34, the optical demultiplexing except that the wavelength band different from that of the third embodiment is targeted. Since it is the same as that of the wave apparatus 35 and the wavelength converter 62-1 to 62-M, detailed description is abbreviate | omitted.

  Here, in the above description of the third and fourth embodiments, the case where the wavelength is changed as illustrated in FIGS. 6 and 9 is illustrated, but the present invention is not limited thereto. That is, as described in the third and fourth embodiments, the optical wavelength division multiplexing communication system 1 according to the present embodiment is different from the optical wavelength division multiplexing communication system 1 that uses a different wavelength band (wavelength band of the wavelength division multiplexed optical signal). Of the wavelength multiplexed optical signals, if an optical signal other than the wavelength band used in the optical wavelength multiplexing communication system 1 is converted into an optical signal in a wavelength band included in the wavelength band used in the optical wavelength multiplexing communication system 1, The wavelength band used in each optical wavelength division multiplexing communication system is not limited to the above example.

  Further, as described in the third and fourth embodiments, during wavelength conversion, among wavelength multiplexed optical signals from different optical wavelength multiplexing communication systems, the wavelength band (wavelength multiplexing) used in the optical wavelength multiplexing communication system 1 is used. In the wavelength band used in the optical wavelength division multiplexing communication system 1, the wavelength band included in the wavelength band not overlapping with the wavelength band of the wavelength multiplexing optical signal in the different optical wavelength multiplexing communication system is used. By converting to an optical signal, it is possible to avoid duplication of the wavelength of the optical signal before and after the conversion.

  Further, as shown in FIG. 6, the wavelength bands to be converted are all the wavelength bands that are not overlapped with the wavelength bands of the wavelength multiplexed optical signals of different optical wavelength multiplexing communication systems in the wavelength band used in the optical wavelength multiplexing communication system 1. Of course, as shown in FIG. 9, it may be determined arbitrarily as a part of a non-overlapping wavelength band. For example, in the fourth embodiment, the wavelength band of the conversion destination may be 1565 nm to 1605 nm instead of 1570 nm to 1610 nm.

<Schematic configuration of the embodiment>
Next, a schematic configuration of the optical wavelength division multiplexing communication system 1 according to the embodiment of the present invention will be described with reference to FIG. FIG. 11 is a schematic configuration diagram of the optical wavelength division multiplexing communication system 1 according to the embodiment of the present invention. That is, the optical wavelength division multiplexing communication system 1 according to the first to fourth embodiments described above can also be understood as an optical wavelength division multiplexing communication system 9 shown in FIG.

  The optical wavelength multiplexing communication system 9 includes transmission side conversion units 100-1 to 100-N, reception side conversion units 101-1 to 101-N, a transmission side multiplexing unit 110, and a reception side demultiplexing unit 111. Yes.

  The transmission side conversion units 100-1 to 100-N are assigned to each of the plurality of wavelength bands λ (1) to λ (N), and the input electric signal is converted into an optical signal in the assigned wavelength band. And output to the transmission side multiplexing unit 110. The transmission side conversion units 100-1 to 100-N correspond to the E / O converters 20-1 to 20-N.

  Receiving side converters 101-1 to 101-N are assigned to each of a plurality of wavelength bands λ (1) to λ (N), and among the plurality of optical signals output from receiving side demultiplexing unit 111 The optical signal in the assigned wavelength band is converted into an electrical signal. The receiving side conversion units 101-1 to 101-N correspond to the O / E converters 21-1 to 21-N.

  The transmission side multiplexing unit 110 multiplexes the plurality of optical signals output from the plurality of transmission side conversion units 100-1 to 100-N, and transmits the multiplexed signal as a wavelength multiplexed optical signal to the reception side demultiplexing unit 111 via the network. Send. The transmission side multiplexing unit 110 corresponds to the optical multiplexing device 30.

  The receiving side demultiplexing unit 111 receives the wavelength multiplexed optical signal transmitted from the transmitting side multiplexing unit 110 via the network, demultiplexes the received wavelength multiplexed optical signal into a plurality of optical signals, and performs reception side conversion. Output to each of the units 101-1 to 101-N. The receiving side demultiplexing unit 111 corresponds to the optical demultiplexing device 31.

  Here, the plurality of wavelength bands include at least a wavelength band including a part of the C band and a wavelength band including a part of the L band, and does not include a wavelength band including other than the C band and the L band. According to this, since it is possible to divert the facilities of the existing C-band and L-band optical wavelength division multiplexing communication systems and to broaden the wavelength band of the wavelength division multiplexing optical signal, while reducing the cost, Broadband can be realized.

  In the above description of the embodiment, the description specifying the range of the wavelength band may be interpreted as including or not including the wavelengths that are the upper limit and the lower limit of the wavelength band. . For example, a wavelength band from 1530 nm to 1560 nm (or 1530 nm to 1560 nm) may be interpreted as a wavelength band of 1530 nm or more or larger and 1560 nm or less.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  In the above-described embodiment, the continuous wavelength band including the wavelength band from 1560 nm to 1570 nm with the wavelength of 1565 nm serving as the boundary between the C band and the L band as the center is set as the wavelength band used in the optical wavelength division multiplexing communication system 1. Although the example has been described, the wavelength band is not limited to the above-described wavelength band as long as it includes at least a part of each of the C band and the L band and does not include other than the C band and the L band. The wavelength band may be discontinuous.

DESCRIPTION OF SYMBOLS 1 Optical wavelength division multiplexing system 2, 3 Wavelength division multiplexing optical signal conversion system 10 Transmission side processing system 11 Reception side processing system 20 E / O converter 21 O / E converter 30, 33, 34, 37, 38 Optical multiplexer 31 , 32, 35, 36, 39 Optical demultiplexing device 40, 41 Optical amplifier 50, 51, 52, 53 Optical fiber 60, 61, 62, 63 Wavelength conversion device 100 Transmission side conversion unit 101 Reception side conversion unit 110 Transmission side combination Wave unit 111 Receiving side demultiplexing unit 200, 201 LD
210, 211 PD

Claims (9)

A plurality of transmission-side converters that are assigned to each of a plurality of wavelength bands, convert the input electrical signal into an optical signal of the assigned wavelength band, and output the optical signal;
A plurality of optical signals output from the plurality of transmission side conversion units, and a transmission side multiplexing unit that transmits the signals as wavelength multiplexed optical signals via a network;
A wavelength-division multiplexed optical signal transmitted from the transmission-side multiplexing unit is received via the network, and the wavelength-division multiplexed optical signal received is demultiplexed into the plurality of optical signals and output;
A plurality of receiving side conversions that are assigned to each of the plurality of wavelength bands and that convert an optical signal in the assigned wavelength band among the plurality of optical signals output from the receiving side demultiplexing unit into an electric signal. And
An external optical signal in which optical signals of a plurality of wavelength bands are combined from another optical wavelength division multiplexing communication system, and the received external optical signal is converted into an optical signal to be converted other than the wavelength band of the wavelength multiplexed optical signal, A demultiplexing unit for demultiplexing and demultiplexing the non-conversion target optical signal in the wavelength band of the wavelength multiplexed optical signal;
A wavelength conversion unit that converts the optical signal to be converted output from the demultiplexing unit for conversion into an optical signal in a wavelength band included in a wavelength band of the wavelength division multiplexed optical signal;
A multiplexing for conversion that combines the non-conversion target optical signal output from the conversion demultiplexing unit and the conversion target optical signal converted by the wavelength conversion unit, and transmits the multiplexed signal to the network as the wavelength multiplexed optical signal And comprising
The plurality of wavelength bands include a wavelength band including at least a part of the C band and a wavelength band including a part of the L band, and does not include a wavelength band including other than the C band and the L band.
Optical wavelength division multiplexing communication system. The plurality of wavelength bands are included from 1560 nm in the C band to 1610 nm in the L band.
The optical wavelength division multiplexing communication system according to claim 1. The wavelength conversion unit converts the optical signal to be converted into an optical signal in a wavelength band included in a wavelength band that does not overlap with a wavelength band of the external optical signal in the wavelength band of the wavelength multiplexed optical signal.
The optical wavelength division multiplexing communication system according to claim 1 . The plurality of wavelength bands are included from 1560 nm in the C band to 1610 nm in the L band,
The external optical signal is an optical signal obtained by combining optical signals of a plurality of wavelength bands included only in the L band,
The conversion demultiplexing unit uses, as the conversion target optical signal, a wavelength band of 1610 nm or larger or larger in the external optical signal.
The optical wavelength division multiplexing communication system according to any one of claims 1 to 3 . The plurality of wavelength bands are included from 1560 nm in the C band to 1610 nm in the L band,
The external optical signal is an optical signal obtained by combining optical signals of a plurality of wavelength bands included only in the C band,
The conversion demultiplexing unit uses a wavelength band of 1560 nm or less or less than the external optical signal as the conversion target optical signal.
The optical wavelength division multiplexing communication system according to any one of claims 1 to 3 . The plurality of wavelength bands includes a wavelength band including a boundary wavelength between the C band and the L band, and becomes a continuous wavelength band.
The optical wavelength division multiplexing communication system according to any one of claims 1 to 5 . The network is a silica-based optical fiber laid to transmit an optical signal obtained by combining optical signals of a plurality of wavelength bands included only in the L band as an optical fiber for transmitting the wavelength-multiplexed optical signal; Including a dispersion compensating optical fiber laid to transmit an optical signal in which optical signals of a plurality of wavelength bands included only in the C band are combined,
The optical wavelength division multiplexing communication system according to any one of claims 1 to 6 . Converting each of the plurality of electrical signals into each of a plurality of optical signals to be in each of a plurality of wavelength bands;
Combining the plurality of optical signals and transmitting as a wavelength multiplexed optical signal over a network;
Receiving the transmitted wavelength multiplexed optical signal via the network, and demultiplexing the received wavelength multiplexed optical signal into the plurality of optical signals;
Converting each of the plurality of demultiplexed wavelength bands into each of the plurality of electrical signals;
An external optical signal in which optical signals of a plurality of wavelength bands are combined from another optical wavelength division multiplexing communication system, and the received external optical signal is converted into an optical signal to be converted other than the wavelength band of the wavelength multiplexed optical signal, Demultiplexing and outputting to the non-conversion target optical signal in the wavelength band of the wavelength multiplexed optical signal;
Converting the optical signal to be converted into an optical signal in a wavelength band included in a wavelength band of the wavelength-multiplexed optical signal;
Combining the non-conversion target optical signal and the conversion target optical signal, and transmitting to the network as the wavelength-multiplexed optical signal ,
The plurality of wavelength bands include a wavelength band including at least a part of the C band and a wavelength band including a part of the L band, and does not include a wavelength band including other than the C band and the L band.
Optical wavelength division multiplexing method. A first receiving unit that receives each of a plurality of optical signals in a plurality of wavelength bands from each of a plurality of electro-optical converters that convert an electrical signal into an optical signal;
A multiplexing unit that multiplexes a plurality of optical signals received by the first receiving unit and generates a wavelength multiplexed optical signal;
A first transmitter that transmits the wavelength multiplexed optical signal generated by the multiplexer via a network;
A second receiving unit for receiving, via the network, a wavelength-multiplexed optical signal obtained by combining a plurality of optical signals in the plurality of wavelength bands;
A demultiplexing unit that demultiplexes the wavelength-multiplexed optical signal received by the second receiving unit and generates the plurality of optical signals;
A second transmitter that transmits each of the plurality of optical signals generated by the branching unit to a plurality of photoelectric converters that convert the optical signal into an electrical signal;
An external optical signal in which optical signals of a plurality of wavelength bands are combined from another optical wavelength division multiplexing communication system, and the received external optical signal is converted into an optical signal to be converted other than the wavelength band of the wavelength multiplexed optical signal, A demultiplexing unit for demultiplexing and demultiplexing the non-conversion target optical signal in the wavelength band of the wavelength multiplexed optical signal;
A wavelength conversion unit that converts the optical signal to be converted output from the demultiplexing unit for conversion into an optical signal in a wavelength band included in a wavelength band of the wavelength division multiplexed optical signal;
A multiplexing for conversion that combines the non-conversion target optical signal output from the conversion demultiplexing unit and the conversion target optical signal converted by the wavelength conversion unit, and transmits the multiplexed signal to the network as the wavelength multiplexed optical signal And comprising
The plurality of wavelength bands include a wavelength band including at least a part of the C band and a wavelength band including a part of the L band, and does not include a wavelength band including other than the C band and the L band.
Optical multiplexing / demultiplexing device.

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