JPH01188040A - Laser beam interruption system - Google Patents

Abstract

PURPOSE:To interrupt a control voltage to an optical switch when an optical connector is removed and to interrupt a radiated beam of a laser diode by supplying the control voltage to the optical switch provided to the output side of a laser diode through a conductor provided to a plug and a receptable of the optical connector. CONSTITUTION:If a subscriber removes a plug 103, for example, conductors 105, 106, 107 are disconnected and no voltage 1017 is supplied to optical switches SW1, SW2, FETs 1002, 1102 and electric switches SEW1, SEW2. Thus, the optical switches SW1, SW2 are opened and the radiated beam of the laser diodes LD1, LD2 is interrupted. Then FETs 1002, 1102 are inoperative and the electric switches SEW1, SEW2 are opened to cause no stimulation to the laser diodes LD1, LD2. Thus, a damage to eyes due to the radiated beam of the laser diode 1107 is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laser beam; +! The present invention relates to a C41 optical tracing system for blocking unnecessary laser light in optical subscriber terminals and the like.

[Conventional technology]

In recent years, with the advancement of the information society, studies are underway to install fiber optics in subscriber lines and provide a variety of broadband and high-speed services such as video in addition to conventional voice and data. .

Such an optical subscriber transmission system is introduced, for example, in the Institute of Electronics and Communications Engineers Technical Research Report C385-148r ``Application Method of Subscriber Single Mode Optical Line and Strap Network Configuration'' (Yamamoto et al.).

FIG. 5 is a block diagram showing an example of a unidirectional transmission side of an optical subscriber transmission system according to the prior art.

According to FIG. 5, the optical subscriber terminal 500 has an optical fiber 501.
It is connected to the subscriber line exchange 502 by.

The configuration of FIG. 5 includes input terminals 5001. FET (field effect transistor) 5002, resistor Rb5003, resistor RM5005, inductance L5004. Monitor photodetector PD5006, laser diode LD5
007, LD bias adjustment circuit IB5008. Voltage comparator vC5009, photodetector APD5021, broadband amplifier AMP5022, output terminal 5023, optical connector 5
03. In FIG. 5, the laser diode LD5007 has a threshold current characteristic, and laser oscillation occurs at this threshold current, and the optical output increases rapidly. Therefore, generally the resistance Rb 500
3. An optimal threshold bias current is supplied to the LD bias adjustment circuit IB5008 via the inductance L5004. On the other hand, the input signal applied to the input terminal 5001 is applied to the FET 5002 and converted into a current swing part according to the input voltage amplitude. This current becomes the driving current for the laser diode LD5007. in this way,
The signal applied to the input terminal 5001 is converted into the intensity of the light emitted from the laser diode LD5007,
Send n to one end of 01.

Additionally, the laser diode LD5007 generally has a tendency for its optical output to change as the ambient temperature changes, and a circuit to keep this optical output constant, that is, an optical output stabilization circuit, is usually essential. There is. In Figure 5,
The monitor photodiode PD5006 receives part of the optical signal power emitted from the laser diode LD5007. This optical signal power becomes a DC voltage component by a capacitor C5012, and is input to a voltage comparator VC5009 via a signal line 5011. This voltage comparator VC
At 5009, the voltage value input from the signal line 5011 is compared with the reference voltage VREF 5010, and the LD bias adjustment circuit outputs a signal tube to 5008 to control the increase/decrease of the bias current. By this, the laser diode LD
The optical signal power emitted from 5007 becomes a constant value. The optical signal thus obtained is transmitted to the subscriber line exchange 502 through the optical connector 503 and the optical fiber 501.

This optical signal enters the light receiving element APD5021 and is converted into an electrical signal, and then is sent to the wideband amplifier AMP5022.
The signal is amplified by and output to a switch network connected to an output terminal 5023.

[Problem that the invention seeks to solve]

In the conventional optical subscriber transmission system described above, for example, in FIG.
03 and looking through its end face, there is a risk that the subscriber's eyes may be damaged by the emitted light from the laser diode LD5007. For this reason, in recent years there has been a movement in Japan to set limits on the amount of laser emitted light based on JIS standards and the like. However, if the amount of light emitted from the subscriber terminal 500 is limited, there is a problem in that the degree of freedom in allocating loss in the optical subscriber transmission system is significantly impaired.

The object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a laser beam blocking method that does not limit the amount of light emitted from the laser diode, does not damage the laser diode itself, and does not damage the subscriber's eyeballs. The goal is to provide a method.

[Means to solve the problem]

The first laser beam blocking method of the present invention includes first and second laser diodes placed at different locations where light is to be transmitted, and a side where the first laser diode is installed and a side where the second laser diode is installed. A laser diode drive circuit is installed on the installation side of the diode to drive the laser diode, and a voltage is provided to supply a bias current to the laser diode via an electric switch and to keep the optical output of the laser diode constant. an optical output stabilizing circuit including a comparator;
) one end is coupled through the original switch and the second
an optical connector for coupling an optical 7 eyer to a laser diode, and a source fiber for coupling the other end via a second source switch, and each conductor is provided in the plug and receptacle of the source connector. A conductor integrated with the redundant fiber is provided to supply a constant voltage as a control voltage to the first and second source switches and a power supply voltage for the laser diode drive circuit and the electrical switch. The optical fiber is passed through the plug, the receptacle, and the optical fiber from the receptacle end of the connector to control the cutoff of the optical output of the fpil laser diode.

Furthermore, the laser beam blocking method of the second invention includes first and second laser diodes placed at different locations where light is to be transmitted, and a side where the laser diode is installed and the second laser diode. a laser diode drive circuit disposed on the installation side of each laser diode to drive the laser diode; an optical output stabilizing circuit equipped with a voltage comparator, one end of which is coupled to the first laser diode via an ff1l optical switch and a first optical multiplexer/demultiplexer, and an optical fiber is connected to the second laser diode. The optical fiber is configured to include an optical connector to be coupled and an optical fiber to be coupled at the other end via a second source switch and a second optical multiplexer/demultiplexer, and a plug and receptacle of the optical connector and the first and second optical fibers. The optical multiplexer is provided with conductors, and further includes a conductor that is attached to and integrated with the original fiber to supply control voltages to the first and second optical switches, the laser diode drive circuit, and the electrical switch. A constant voltage as a power supply voltage is supplied from the receptacle end of the original connector through the plug, the receptacle, the first and second optical multiplexer/demultiplexer, and a conductor installed in the optical fiber, thereby blocking the optical output of the laser diode. It is characterized by controlling.

Furthermore, the laser light blocking method of the third aspect of the present invention includes a first laser diode and a light receiving element, a second laser diode and a light receiving element, and a second laser diode and a light receiving element disposed at different locations where light is to be transmitted; a laser diode drive circuit disposed on the installation side of the diode and the installation side of the second laser diode to drive the laser diode; an optical output stabilizing circuit including a voltage comparator for making the output constant; and a first laser diode connected to the first laser diode.
One end is coupled through the optical switch and the first optical multiplexer/demultiplexer, and the optical fiber is fully coupled to the second laser diode in fi111 through the original connector and the second optical switch and the second optical multiplexer/demultiplexer. an optical fiber whose other end is coupled to the first light receiving element via a third optical switch, and whose other end is coupled to the first optical multiplexer/demultiplexer;
an optical fiber coupled through an optical switch, and an optical fiber coupled at one end to the second light receiving element and at the other end coupled to the second optical multiplexer/demultiplexer via a fourth optical switch. Each conductor is provided in the plug and receptacle of the optical connector and the first and second optical multiplexer/demultiplexer, and further a conductor is provided and integrated with the optical fiber. A control voltage to the optical switch, the laser diode driving circuit, and a constant voltage as the electric switch power supply voltage are supplied from the receptacle end of the optical connector to the plug and receptacle, the first and second optical multiplexer/demultiplexer, and the optical switch. The method is characterized in that cutting off of the optical output of the laser diode is controlled by passing through a conductor installed in an optical fiber.

Furthermore, the laser light blocking method of the fourth invention includes a first laser diode and a light receiving element, a second laser diode and a light receiving element, and a second laser diode and a light receiving element disposed at different locations where light is to be transmitted. a laser diode drive circuit disposed on the installation side of the diode and the installation side of the second laser diode and driving the laser diode; a bias adjustment circuit supplying a bias voltage to the laser diode; a voltage conversion circuit that generates a voltage; a laser light monitor circuit that receives a portion of the laser light emitted from the laser diode and generates a monitor voltage having a magnitude corresponding to the intensity of the laser light; a first voltage comparator that compares the output voltage of the first voltage comparator and the second voltage; a first voltage comparator that compares the output voltage of the first voltage comparator with the second voltage; One end is coupled to the second laser diode through a switch and a first optical multiplexer/demultiplexer, and the other end is coupled to the second laser diode through a second optical switch and a second optical multiplexer/demultiplexer. an optical fiber whose ends are coupled, and an original fiber whose one end is in contact with the first light receiving element and the other end is in contact with the first optical multiplexer/demultiplexer via a third optical switch.

One end is coupled to the second light receiving element, and the second
and an original fiber whose other end is coupled to the optical multiplexer/demultiplexer via a fourth optical switch, and each conductor is connected to the plug and receptacle of the optical connector and the first and second optical multiplexer/demultiplexer. Further, a conductor is installed and integrated with the original fiber, and supplies a constant voltage as a control voltage to the first to fourth optical switches and a power supply voltage of the voltage conversion circuit to the receptacle end of the optical connector. The present invention is characterized in that cutting off of the optical output of the laser diode is controlled through conductors installed in the plug and receptacle, the first and second optical multiplexer/demultiplexers, and the original fiber.

[Effect]

The first to fourth inventions provide an optical switch subordinate to the output side of a laser diode, and supply a control voltage to the optical switch through a plug of an optical connector and a conductor provided in a receptacle. When the connector is disconnected, the control voltage to the original switch is Mrg′r.
By blocking the emitted light from the laser diode, it is possible to prevent the subscriber's eyeballs from being damaged by the emitted light from the laser diode.

〔Example〕 Next, the present invention will be explained using the drawings.

FIG. 1 is a block diagram showing an embodiment of the first invention. In FIG. 1 as well as in FIG. 5, the optical subscriber terminal lOO is
An optical fiber 101 is connected to a subscriber line exchange 102, illustrating a mode of bidirectional optical transmission.

The embodiment of FIG. 1 has input terminals 1001 and 1101°FE.
T1002, 1102, resistance Rb1003, 1103
.

Resistance RM1005, 1105, inktance L10
04e1104,% Nita-7*Todetech:p-PD1
006°1106, laser diode LDI (1007
, ), LD2 (1107), LD pipe, ;<From paw circuit 1 (1oo8), IB2 (11o8), voltage comparator VCIθ001. VC2 (1109, l, capacitor p
1012.1112% III pressure source 1017. V sector 104, plug 103, conductors 105, 106, 1
07° Photodetector APD1021, 1121, broadband amplifier AMP1022.1122, output terminal 1023, 11
23, optical multiplexer/demultiplexer 108, 109, optical switch SW
1 (1013).

SW2 (1113), electric switch 5EWI (101
4).

5EW2 (1114).

The optical connector includes a plug 103 and a receptacle 10.
Composition by 4 is disgusting. In the receptacle 104,
Two conductors 105 and 107 are provided in the plug 103, and these two conductors 105 and 107 are connected by a conductor 106 provided in the plug 103. Further, the original fiber 101 is coated with metal by vapor deposition or the like, and is electrically connected to a conductor 106.

The input signal applied to input terminals 1001.1101 is
Laser diode by FET1002, 1102)
LD 1 (100υ, LD 2 (1107,)'t
- converted into a driving current to drive. On the other hand, the threshold bias current to the laser diode LDI(100v, LD2(110ψ) is LD bias adjustment circuit 4I B 1(1
008), I B 2 (110g) Yostain Switch 5EWI (1014).

5EW2 (1114) and resistance Rb1003,110
3. Supplied through inductances L1004 and 1104 and superimposed on the drive current signal to the laser diodes LD 1 (1007) and LD 2 (1107), respectively.
to drive. This electric switch 5EW1.5EW2 is
It is conductive when voltage is applied.

The monitor photodiode PD1006.1106 is
Laser diode LDI, LD2 (1007, 1107
) receives part of the original signal power emitted from the This optical signal is converted into an electrical signal, and its direct θIt component is further controlled! Voltage comparator VCI via 1toxt, xxtx
, VC2 (1009, 1109).

Ko (7)! Pressure comparison 1Vc1. VC2 (1009,110
In 9), compare the reference voltage Viar1010.1110 and the voltage input from the control line 1011°1111,
LD bias adjustment circuit IBI, IB2 (1008, 11
08), outputs a voltage that controls the threshold bias current to be constant. In this way, the laser diodes LDl, LD2 (1007, 1107) are
It is possible to always emit constant optical signal power.

Laser diode LD 1. LD 2 (1007
, 1107) The emitted optical signal is sent to the optical switch SW.
I.

It is coupled to the optical fiber via SW2 (1013, 1113).

The optical switches SWI and SW2 are in a conductive state when a control voltage is applied. The control voltage is supplied to FET1002, electric switch 5EW11 and optical switch SWI from voltage source 1017 to conductor 105-conductor 106-
Conductor 107-FET 1002, electrical switch 5EWI
, is performed along the path of the optical switch SW1. At the same time, the control voltage is also supplied to the FET 1102, the electric switch 5EW2, and the original switch SW2 through the path of the conductor 106 and the optical fiber 101. Therefore, for example, when a subscriber pulls out plug 103, this causes conductor 105, conductor 106, conductor 1
07 is disconnected, and the optical switch sw is disconnected from the voltage source 1017.
i.

SW2. Voltage is no longer supplied to FETs 1002 and 1102 and electrical switches 5EWI and 5EW2.

Therefore, when the optical switches SWI and SW2 are in an open state, they can block the light emitted from the laser diodes LDI and LD2. Furthermore, FETs 1002 and 1102 are in a non-operating state, and further, electric switches 5EWI and 5EW2 are in an open state, and laser diodes LDI and LD2 are in an open state.
becomes a non-emitting state.

In this way, in this embodiment, when the subscriber pulls out the plug 103, the emitted light from the laser diode 1007 on the subscriber terminal 100 side and the emitted light from the laser diode 1107 on the exchange 102 side can cause damage to the eyeball, etc. At the same time, it can be prevented from giving.

Next, the second invention will be explained. The second invention is, for example, the first invention in the embodiment of the first invention shown in FIG.
This is done so that even when the original fiber is cut at points A and B shown in the figure, it is possible to block the laser light emitted from the cut surface.

FIG. 2 is a block diagram showing an embodiment of the second invention. Similarly to FIG. 5, FIG. 2 also shows an aspect of bidirectional optical transmission, in which an optical subscriber terminal 100 is connected to a subscriber line exchange 102 by an optical 7-IPer 101). Below, a detailed explanation will be given of the differences from FIG. 1, and redundant detailed explanations of the same contents will be omitted.

The optical connector includes a plug 103 and a receptacle 10.
It is composed of 4. In the receptacle 104,
Furthermore, two conductors 105.2 (17) are provided, and these two conductors 105 and 207 are connected by a conductor 106 provided in the plug 103.Furthermore, the original fiber 101 is coated with metal by, for example, vapor deposition. The conductor 106 and the conductor 106 are electrically connected to each other.

``Metal is also deposited on the original fibers 2082, 2083, and 2092. Conductors 2081 and 2091 are inserted into the optical multiplexer and demultiplexer 208 and 209, respectively, and the conductor 2081 is connected to optical fibers 2082 and 2083, and
91 is electrically connected to the optical fibers 101 and 2092. The receptacle 1040 exclusive body 207 is also electrically connected to the optical fiber 2083.

The input signal applied to input terminals 1001.1101 is
Laser diode L by FET1002, 1102
It is converted into a drive current that drives DI and LD2 (1007, 1107). On the other hand, the laser diode LDI, L
The threshold bias current to D2 is determined by the LD bias adjustment circuits IBI, IB2 (1008°1108) and the stain switches 5EWI, 5EW2 (1014).

1114), is supplied through the resistor Rb1003.1103 and the inductance L1004.1104, and is superimposed on the drive current signal to drive the laser diodes LDI, LD2,
Drive. The electric switches 5EWI and 5EW2 are conductive when voltage is applied. Monitor photodetector PD 1006.1106 is
A portion of the original signal power emitted from the laser diodes LDI and LD2 is received. This optical signal is converted into an electrical signal and its DC component is sent to the control line 1011.1111 t
-Sake Te! Pressure comparison WV C1, VC2 (1009, 11
09). This voltage comparator MCI, u at VC2, reference voltage VREF1010.1110 and control line 10
11. Compare the voltage input from 1111 with the voltage input from LD bias adjustment circuit mlB1. A voltage is outputted to IB2 to control the threshold bias current to be constant. In this way, the laser diodes LDI and LD2 can always emit constant original signal power. The optical signal μ emitted from the laser diodes LDI and LD2 passes through the original switches SWI and SW2 to the optical fiber 2082°209.
2. This optical switch SWI.

SW2 is in a conductive state when the control voltage is applied. The supply of control voltage to the FET 1002, the electric switch 5EWI, and the optical switch SW1 is provided by the voltage source 101.
From 7, conductor 105-'4 body 106-conductor 107-optical fiber 2083-conductor 2081-optical fiber 2082-F
ET H2O2, electric switch 5EWI, optical switch S
This is done via route W1.

At the same time, conductor】06-Optical fiber 101-m body 209
A control voltage is also supplied to the FET 1102, the electric switch 5EW2, and the optical switch SW2 through the path of the 1-element fiber 2092. Thus, for example, when a subscriber pulls out the plug 103, this causes the plug 105, the conductor 106, and the conductor 1
07 is disconnected and the original switch SWI is disconnected from the voltage source 1017.
, SW2. Voltage is no longer supplied to FETs 1002 and 1102 and electrical switches 5EWI and 5EW2. Therefore, when the optical switches swi and sw2 are in an open state, they can block the light emitted from the laser diodes LDI and LD2. Furthermore, FETs 1002 and 1102 become inactive, and electric switches 5EWI and 5EW2 become open, so that the laser diode LD 1007
.

1107 is in a non-emission state. Also, former Fino Ku 20
82. Even if disconnection occurs at points A and B of 2092, the FET
1002, 1102, electrical switch 5EWI.

5EW2, the voltage is no longer supplied to the optical switches SWI and SW2. Therefore, laser light can be blocked.

Thus, in the second inventive embodiment, when the subscriber pulls out the plug 103.

Emitted light from the laser diode 1007 on the subscriber terminal 100 side and the laser diode 11 on the subscriber line exchange 102 side
At the same time, it is possible to prevent damage to the eyeballs etc. caused by the emitted light of 07.

FIG. 3 is a block diagram showing an embodiment of the third invention. The third invention makes it possible to block the laser light emitted from the cut surface even when the original fiber is cut at points C and D shown in FIG.

Similarly to FIG. 5, the third example also shows an optical subscriber terminal 100 connected to a subscriber line exchange 102 by an optical fiber 101, and exhibits a mode of bidirectional optical transmission. Below is the first
A detailed explanation will be given of the differences from FIG. 2, and a detailed explanation of the same contents will be omitted.

The optical connector includes a plug 103 and a receptacle 104.
It is made up of. The receptacle 104 is further provided with two conductors 105 and 207.
The two conductors 105 and 207 are connected by a conductor 106 provided on the plug 103. Furthermore, the original 7 Aipa 10
1 is coated with metal, for example by vapor deposition,
It is electrically connected to the conductor 106. Also, the original fiber 2082.2083.2092.3082.3092
Metals are also vapor-deposited. Optical multiplexer/demultiplexer 208, 209
Conductors 2081 and 2091 are interpolated respectively.

Conductor 2081 connects optical fibers 2082, 2083 and conductor 2
091 is electrically connected to optical fibers 101 and 2092. The conductor 207 of the receptacle 104 is also electrically connected to the original fiber 2083. Furthermore, the metal deposited on the optical fibers 3082 and 2082, and 3092 and 2092 are electrically connected, so that they are electrically connected. Therefore, the optical fibers 2082, 3082, 20
83, 101, 2092, 3092, conductor 2081, 2
07, 106, and 2091 are all conductive when the original connectors 104 and 103 are connected.

The input signal applied to input terminals 1001.1101 is
Laser diode L by FET1002.1102
It is converted into a drive current that drives DI and LD2.

On the other hand, the threshold bias current to the laser diodes LDI and LD2 is supplied to the LD bias adjustment circuit IBI.

IB2) Electrical switch 5EWI, 5EW2, resistance Rh1003.1103, inductance L10
04.1104 and is superimposed on the drive current signal to drive the laser diodes LDI and LD2. This electric switch 5EW1.5EW2 is conductive when a voltage is applied. The monitor photodiodes PD1006 and 1106 are laser diodes LI)1. A portion of the optical signal power emitted from the LD 2 is received. This optical signal is converted into an electrical signal, and its DC component is further input to voltage comparators VC1 and VC2 via control lines 1011.1111.

In this voltage comparator MCI, VC2, the reference voltage VREF
1010, 1110 and the voltages input from the control lines 1011 and 1111, the LD bias adjustment circuit I
A voltage is outputted to BI and IB2 to control the threshold bias current to be constant. In this way, the laser diodes LDI and LD2 can always emit constant optical signal power.

The original signal emitted from the V-the diodes LDI and LD2 is sent to the optical fiber 20 via the optical switch SWI and 5W2ft.
82.2092. Transmitted optical signal color D1
;λ1. LD2:λ2), λ1 is the original fiber 3092
from APD11 via optical switch SW4 (3113)
21, and λ2 is received by the APD 1021 from the original fiber 3082 via the optical switch SW3 (3013). The original switches SW3 and SW4 are the optical multiplexer/demultiplexer 20
It must be installed at the near end of 8,209. This optical switch SWI.

SW2. SW3. SW4 is in a conductive state when a control voltage is applied. FET1002, 1102,
The control voltage is supplied to the electric switch 5EWI and the optical switch SWI from the voltage source 1017 to the multi-conductor 105-conductor 106.
- Conductor 107 - Optical fiber 2183 - Conductor 2081 - Optical fiber 2082 - FETs 1002 and 1102, electrical switches SF and W 1 , and optical switch SWI. Therefore, the optical switch SW3 also has an optical 7-iper 20
82 - A control voltage is applied in the optical fiber 3082 path. ° At the same time, FET 1102 is connected to the conductor 106-optical fiber X0X-s body 2091-optical fiber 2092 path.
, the electric switch 5EW2, and the original switch SW2 are also supplied with the control voltage. Furthermore, the control voltage is also supplied to the optical switch SW4 through the path from the original fiber 2092 to the ninth fiber 3092. From optical fiber 3282.3092 to optical switch SW3. The control voltage is supplied to sw4 from the original fiber 3.
This is done from the output end of 282.3092.

Therefore, for example, when a subscriber pulls out the plug 103, the conductors 105, 106, and 107 are disconnected and the voltage source 1017 is connected to the optical switches SWI, SW2, . S
W3. SW4. FET1002゜1102, electric switch 5EW1. Voltage is no longer supplied to SEw2.

Therefore, the optical switch SWI.

SW2. SW3. When SW4 is in an open state, it can block the light emitted from the laser diodes LDI and LD2. Further, the FETs 1002 and 1102 are in a non-operating state, and the electric switches 5EWI and 5EW2 are in an open state, so that the laser diode LD1.2 is in a non-emitting state. Also, even if the break occurs at points A and B of the Tsum fiber or points 0 and D of the optical fiber, the original switch SV/1°8W2. SW3. SW4. FET1
002,1102% No voltage is supplied to the electric switch 5EW1.5EW2. Therefore, the laser beam can be blocked.

In this way, in the embodiment of the present invention, when the subscriber pulls out the plug 103, the emitted light from the laser diode 1007 on the subscriber terminal 100 side and the emitted light from the laser diode 1107 on the exchange 102 side may cause damage to the eyeballs, etc. Damage can be prevented at the same time.

FIG. 4 is a block diagram showing an embodiment of the fourth invention. Similarly to FIG. 5, FIG. 4 also shows an aspect in which the optical subscriber terminal 100 is connected to the subscriber line exchange 102 by an optical fiber 101, and the same party is transmitted on both sides. The fourth aspect of the present invention is to eliminate the possibility of damage to the surge voltage laser diode due to direct interruption of the LD bias current due to 5EWI,2.

The 4' invention will be explained in detail by focusing on the points that are different from the embodiments of the 1st to 3rd inventions, and detailed explanations of the same content will be omitted.

The optical connector includes a plug 103 and a receptacle 104.
It is made up of. The receptacle 104 is further provided with two conductors 105 and 207.
The two conductors 105 and 207 are connected by a conductor 106 provided on the plug 103. Furthermore, the original fiber 10
1 is coated with metal, for example by vapor deposition,
It is electrically connected to the conductor 106. Also optical fibers 2082, 2083, 2092.3082.3092
Metals are also vapor-deposited. Optical multiplexer/demultiplexer 208, 209
Conductors 2081 and 2091 are inserted into each of the conductors 2081 and 2091, respectively, and the conductor 2081 is electrically connected to the optical fibers 2082 and 2083, and the conductor 2091 is electrically connected to the optical fibers 101 and 2092. The conductor 207 of the receptacle 104 is
It is also electrically connected to the original fiber 2083. Further, the metals deposited on the optical fibers 3082 and 2082, 3092 and 2092 are electrically connected, so that they are electrically connected. Therefore, Hikari 7 Aiper 2082, 3082, 2
083.101, 2092°3092, conductor 2081,
207,106.2091 is optical connector 104.103
All are conductive when connected.

The input signal applied to input terminals 1001.1101 is
Laser diode L by FET1002.1102
It is converted into a drive current that drives DI and LD2. This F
The power supply voltage of ET1002.1102 is determined by voltage conversion circuit D.
CV1. DCV2 (4011, 4111) control line 7
, 8. In addition, this voltage i conversion times MD
Cv1. DCV2 (4011, 4111)h control line 1,
4 to the second voltage comparator VCl2.4. VC
Occurs for 22. On the other hand, laser diode LDI
, the threshold bias current to LD2 is determined by the LD bias adjustment circuit MIBI, IB2 and the resistors Rh1003, 1103.
, inductance L 1004 .

1104 and is superimposed on the drive current signal to drive the laser diodes LDI and LD2.

The monitor photodiode PD1006, 1106 is
A portion of the optical signal power emitted from the laser diodes LDI and LD2 is received. This optical signal is converted into an electrical signal and its DC component is sent to the first voltage comparator VCII via control lines 1011.1111.

It is input to VC21. This first voltage comparator VC11
, VC21a, , reference voltage VREF 1010 , 11
10 and the voltage input from the control lines 1011.1111, and outputs a voltage to control the threshold bias current to be constant to the LD bias adjustment circuits IBI and IBZ. Second voltage comparator VCl2. At VC22, the first voltage comparator VCII.

Voltage value input from VC21 and voltage conversion circuit DCV1
．． Input from DCV2 through control lines 1 and 4! bi
Comparison is made with the lJ control voltage, and the LD bias adjustment circuit r-6
IB1. A voltage is output to control IBZ so that the threshold one point bias current is constant.

This second voltage comparator VCl2. In VC22, it is usually the first
The LD bias adjustment circuits IBI and IBZ are controlled depending on the output voltages of the voltage comparators VC11 and VC21, but when the voltages of the control lines 1 and 4 fall below a predetermined value, the threshold bias current becomes zero. Output the control voltage as follows. In this way, the laser diodes LDI and LD2 are
It is possible to always emit constant original signal power. Optical signals emitted from the laser diodes LDI and LD2 are coupled to the optical fiber via the source switches SWI and SW2. The transmitted optical signal (LDI: λ1. LD2: λ2) has λ1 from the optical fiber 3092, passes through the optical switch SW4, and is received by the APD 1121, and λ2 is received by the original fiber 308.
2, the light is received by the APD 1021 via the optical switch SW3. The optical switches S w3 and SW4 need to be installed near the ends of the optical multiplexer/demultiplexer 208 and 209. These optical switches SWx, SW2°SW3. SW4 is in the interrogation state when the control voltage is applied. During normal operation, a certain voltage value is output from the voltage conversion circuits ncvt and DCV2 to the control lines 1.4 and 7.8. The control voltage is supplied to the voltage conversion circuit DC1 and the main switch SW1 from the voltage source 1017 to the conductor 105 to the conductor 1.
06-Conductor 107-Optical fiber 2083-'4 body 208
1-optical fiber 2082-ffi pressure conversion circuit DCV1,
This is done through the optical switch SW1.

Therefore, the control voltage of 15 can be applied to the optical switch SW3 through the optical fiber 2082-optical 7-iper 3082 path. At the same time, 4 bodies 106 - original fiber 101 - conductor 2091
- Voltage conversion circuit DCV2 on the path of Kuunaipa 2092,
A control voltage is also supplied to the optical switch SW2. Furthermore, the control voltage is also supplied to the optical switch SW4 through the path from the original fiber 2092 to the optical fiber 3092. Former 7 Aiba 32
82°3092 to optical switch SW 3, S
The control voltage supply to W4 is via optical fiber 3282.3.
There is a current signal from the output terminal of 092.

Therefore, for example, when a subscriber pulls out the plug 103, the conductor 105, conductor 106, and conductor 107 are disconnected, and the voltage converter circuits DCVI and DCV are disconnected from the voltage source 1017.
2, ft, SW 1°SWz, SW3. SW
4 is no longer supplied with voltage. Therefore, the original switch S
WI, SW2. SW3 and SW4 are in an open state and can block the emitted light from the laser diodes LDI and LD2.

Furthermore, the voltages of control lines 1.4 and 7.8 are approximately Oω,
FETs 1002 and 1102 are inactive, and the LDL-like bias current is zero).Laser diode LDI,2 is in a non-starting state. In addition, even if a break occurs at points A and B of the optical fiber or points C and D of the optical fiber, the optical switches SWI and SW
2. SW3. SW4, voltage conversion circuit DCVI, DCV2
Voltage is no longer supplied to the Therefore, laser light can be blocked.

In this way, in the embodiment of the present invention, when the subscriber pulls out the plug 103, the emitted light from the laser diode 1007 on the subscriber terminal 100 side and the emitted light from the laser diode 1107 on the exchange 102 side may cause damage to the eyeballs, etc. Damage to the optical element can be prevented and the life of the optical element can be maintained.

〔Effect of the invention〕

As described above, according to the present invention, a laser diode cutoff method is provided that does not limit the amount of light emitted from the V-the diode, and also does not damage the laser diode or damage the subscriber's eyeballs. There is an effect that can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the first invention, FIG. 2 is a block diagram showing an embodiment of the second invention, and FIG.
The figure is a block diagram showing an embodiment of the present invention g3, FIG. 4 is a block diagram showing an embodiment of the fourth invention, and FIG. 5 is a block diagram showing an optical subscriber transmission system according to the prior art. be. In the figure, 1 to 8, 1011, 1111.5011... Control line, 100°500... Optical subscriber terminal, 10
1,501,2082°2083.2092.3092
...Optical fiber, 102°502...
Participating line-saving switch, 103...Plug, 104.
...Receptacle, 105, 106, 107, 2
07゜2081.2091・・・Conductor, 108,
109,208.209---Optical multiplexer/demultiplexer, 10
02.1102.5002... Field effect transistor (FET), 1003,1005°1103.1
105.5003.5005...Resistance, -10
04゜1104.5004...Inductance, 1006゜1106.5006...Monitor photodiode (PD), 1007,1107,50
07... Laser diode (LD, LDl, L
D2), 1008.1108°5008...L
D bias adjustment circuit (IB, IBI. IB2), 1009.1109.4019.4009,
4109°4119.5009--Voltage comparator (VC, VCI. VC2, VCll, VCl2. VC21, VC22),
1010°1110.5010 ...-Standard! Pressure (V
REF), 1013°1113.3013.3113・
...... Original switch (SWI. SW2.SW3.5W4), 1017... Voltage source (V), 1021.1121.5021...
Light receiving element API), 1022.1122.5022...
... Wideband amplifier (AMP). Agent Patent Attorney Oto Uchihara

Claims (4)

[Claims] (1) First and second laser diodes placed at different locations where light is to be transmitted, and the laser diode placed on the installation side of the first laser diode and the installation side of the second laser diode respectively. an optical output stabilizing circuit comprising: a laser diode driving circuit for driving a diode; and a voltage comparator for supplying a bias current to the laser diode via an electric switch and for keeping the optical output of the laser diode constant; , one end is coupled to the first laser diode via a first optical switch, and the other end is coupled to the second laser diode via an optical connector that couples an optical fiber and a second optical switch. The plug and the receptacle of the optical connector are provided with respective conductors, and further a conductor is provided and integrated with the optical fiber to connect the first and second optical switches. A constant voltage is supplied as a control voltage and a power supply voltage for the laser diode drive circuit and the electric switch from the receptacle end of the optical connector through the plug and a conductor installed in the receptacle and the optical fiber, thereby controlling the optical output of the laser diode. A laser light blocking method characterized by controlled blocking. (2) first and second laser diodes placed at different locations where light is to be transmitted, and a first laser diode placed on the installation side of the first laser diode, and a second laser diode placed on the installation side of the second laser diode, respectively; a laser diode drive circuit that drives a diode; and an optical output stabilization circuit that includes a voltage comparator that supplies a bias current to the laser diode via an electric switch and keeps the optical output of the laser diode constant; an optical connector that couples one end to the first laser diode via a first optical switch and a first optical multiplexer/demultiplexer, and an optical connector that couples an optical fiber to the second laser diode; a second optical multiplexer/demultiplexer, and an optical fiber that connects the other end via a second optical multiplexer/demultiplexer, and each conductor is provided in the plug and receptacle of the optical connector and the first and second optical multiplexer/demultiplexer; A conductor integrated with the optical fiber is provided to supply a constant voltage as a control voltage to the first and second optical switches and a power supply voltage of the laser diode drive circuit and the electrical switch to the connector. A laser beam cutoff method characterized in that the plug, the receptacle, the first and second optical multiplexer/demultiplexer, and a conductor installed in the optical fiber are passed through the receptacle end of the laser diode to control the cutoff of the optical output of the laser diode. . (3) A first laser diode, a light receiving element, and a second laser diode and a light receiving element disposed at different locations where light is to be transmitted, and a side where the first laser diode is installed and the second laser. A laser diode drive circuit that is arranged on each side of the diode and drives the laser diode, and a voltage comparator that supplies a bias current to the laser diode via an electric switch and keeps the optical output of the laser diode constant. an optical output stabilization circuit comprising an optical output stabilizing circuit, one end of which is coupled to the first laser diode via a first optical switch and a first optical multiplexer/demultiplexer, and an optical fiber is coupled to the second laser diode. an optical fiber whose other end is coupled to the optical connector via a second optical switch, a second optical multiplexer/demultiplexer, and a third optical switch; an optical fiber whose other end is coupled to the optical multiplexer/demultiplexer via a third optical switch; one end is coupled to the second light receiving element and the other end is coupled to the second optical multiplexer/demultiplexer via a fourth optical switch; and an optical fiber coupled through a switch, and each conductor is provided in the plug and receptacle of the optical connector and the first and second optical multiplexer/demultiplexer, and is further attached to and integrated with the optical fiber. A conductor is provided to supply a control voltage to each of the first to fourth optical switches and a constant voltage as a power supply voltage for the laser diode drive circuit and the electric switch from the receptacle end of the optical connector to the plug and receptacle. A laser beam cutoff method, characterized in that the cutoff of the light output of the laser diode is controlled by passing through a conductor installed in the first and second optical multiplexer/demultiplexer and the optical fiber. (4) A first laser diode, a light receiving element, and a second laser diode and a light receiving element disposed at different locations where light is to be transmitted, and a side where the first laser diode is installed and the second laser. a laser diode drive circuit disposed on the installation side of the diode and driving the laser diode; a bias adjustment circuit supplying a bias current to the laser diode; a voltage conversion circuit generating first and second voltages; a laser light monitor circuit that receives a portion of the laser light emitted from the laser diode and generates a monitor voltage corresponding to the intensity of the laser light; and a first voltage comparator that compares the monitor voltage with a reference voltage. , a second voltage comparator that compares the output voltage of the first voltage comparator and the second voltage;
an optical connector that couples one end to the first laser diode via a first optical switch and a first optical multiplexer/demultiplexer, and an optical connector that couples an optical fiber to the second laser diode; an optical fiber whose other end is coupled to the first optical multiplexer/demultiplexer via a second optical multiplexer/demultiplexer; one end is coupled to the first light receiving element, and the other end is coupled to the first optical multiplexer/demultiplexer via a third optical switch; an optical fiber having one end coupled to the second light-receiving element and the other end coupled to the second optical multiplexer/demultiplexer via a fourth optical switch; Each conductor is provided in the plug and receptacle of the connector, and the first and second optical multiplexer/demultiplexer, and further, a conductor is provided that is attached to and integrated with the optical fiber, and the conductor is connected to each of the first to fourth optical switches. A constant voltage is supplied as a control voltage and a power supply voltage of the voltage conversion circuit from the receptacle end of the optical connector to the receptacle of the plug and the first and second receptacles.
A laser beam cutoff method, characterized in that the cutoff of the optical output of the laser diode is controlled through a conductor installed in the optical multiplexer/demultiplexer and the optical fiber.