WO2021106031A1 - Light amplifier, light transmission system, and light amplification method - Google Patents

Light amplifier, light transmission system, and light amplification method Download PDF

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Publication number
WO2021106031A1
WO2021106031A1 PCT/JP2019/045919 JP2019045919W WO2021106031A1 WO 2021106031 A1 WO2021106031 A1 WO 2021106031A1 JP 2019045919 W JP2019045919 W JP 2019045919W WO 2021106031 A1 WO2021106031 A1 WO 2021106031A1
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WO
WIPO (PCT)
Prior art keywords
light
optical
signal
output
optical amplifier
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PCT/JP2019/045919
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French (fr)
Japanese (ja)
Inventor
峻 近森
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三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2019/045919 priority Critical patent/WO2021106031A1/en
Publication of WO2021106031A1 publication Critical patent/WO2021106031A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal

Definitions

  • This disclosure relates to an optical amplifier.
  • the optical amplifier amplifies the optical level of the input signal light and outputs it. At that time, the optical amplifier generates high-power light.
  • the optical amplifier may have an eye-safe function that reduces the light output.
  • the optical amplifier described in Patent Document 1 has an optical amplifier unit that photoamplifies signal light input from an input end and outputs it from an output end, and reflected light and / or return light input to the own machine from the output end.
  • the branch portion that branches the light composed of light, the light receiving element that receives the light branched by the branch portion and detects the light level, and the light level detected by the light receiving element are equal to or higher than a preset first threshold value.
  • it is provided with a control circuit that reduces the amount of light amplification in the light amplification unit.
  • the cause of the return light returning into the optical amplifier is the input of light from an external device connected to the output end of the optical amplifier. ..
  • the output fiber disconnection is determined based on the light level of the return light, there is a problem that the return light input from the external device may be erroneously recognized as the output fiber disconnection.
  • An optical amplifier that photoamplifies signal light has a drive unit that modulates the excitation light for optical amplification with an identification signal that identifies the optical amplifier, and an excitation light that is output from the drive unit to photoamplify the signal light and output light. It detects the optical amplifier that outputs to the outside and the return light whose propagation direction is opposite to that of the output light, and controls to lower the output level of the excitation light when the return light contains the identification signal of the self-optical amplifier. It is equipped with a detection unit.
  • FIG. 1 It is a block diagram which incorporated the optical amplifier 1 which concerns on Embodiment 1 into an optical transmission system. It is a block diagram of the optical amplifier 1 which concerns on Embodiment 1.
  • FIG. It is explanatory drawing which shows an example of the operation of an optical transmission system 10. It is explanatory drawing which shows another example of operation of an optical transmission system 10. It is a flowchart which shows an example of the processing flow of an optical amplifier 1. It is a block diagram which shows the optical transmission system 11 which concerns on the modification 1 of Embodiment 1.
  • Embodiment 1 The optical amplifier 1 photoamplifies the signal light. For example, the optical amplifier 1 photoamplifies and outputs the input signal light.
  • Optical amplifiers are incorporated in various optical transmission systems. Optical amplifiers are also used in communication systems capable of optical transmission in "multi-way", that is, multi-way optical transmission systems and the like.
  • the multi-way optical transmission system includes, for example, a WDM (Wavelength Division Multiplexing) system, a ROADM (Reconfigurable Optical Add Multiplexer) system, and an OXC (Optical Cross Connect) system.
  • WDM Widelength Division Multiplexing
  • ROADM Reconfigurable Optical Add Multiplexer
  • OXC Optical Cross Connect
  • an optical amplifier is used to optically amplify the signal light.
  • optical amplifier 1 according to the first embodiment will be described in detail with reference to the drawings.
  • the following first embodiment shows a specific example. Therefore, the shape, arrangement, material, etc. of each component are examples and are not intended to be limited. Moreover, each figure is a schematic view and is not exactly illustrated. Further, in each figure, the same components are designated by the same reference numerals.
  • FIG. 1 is a configuration diagram showing an example of a case where the optical amplifier 1 according to the first embodiment is incorporated in the optical transmission system 10.
  • the optical transmission system 10 selects and outputs an arbitrary signal light from, for example, a plurality of signal lights.
  • the optical transmission system 10 selects a plurality of arbitrary signal lights, multiplexes the wavelengths, and outputs the light.
  • the optical transmission system 10 includes a switch 4 and an optical amplifier 1.
  • the optical transmission system 10 can include a transponder 2 and an optical combiner 3.
  • the transponder 2 outputs a signal light.
  • the transponder 2 converts, for example, into signal light having a specific wavelength.
  • the transponder 2 is, for example, an interface module.
  • optical combiner 3 multiplexes a plurality of signal lights.
  • the optical combiner 3 multiplexes signal lights having different wavelengths, for example.
  • optical amplifier 1 photoamplifies the signal light.
  • the optical amplifier 1 photoamplifies, for example, the multiplexed signal light.
  • the switch 4 selects and outputs an arbitrary signal light from a plurality of input signal lights.
  • the switch 4 multiplexes and outputs, for example, the selected signal light.
  • the switch 4 is, for example, WSS (Wavelength Selective Switch), WDM, ROADM, OXC, or the like.
  • the switch 4 includes an input port 5 and an output port 6.
  • the switch 4 may include a plurality of input ports 5.
  • the switch 4 may include a plurality of output ports 6.
  • the switch 4 may include an optical element 7 and a mirror 8.
  • the optical element 7 guides light of a specific frequency from a specific input port 5 to a specific mirror 8. Further, the optical element 7 guides light of a specific frequency from a specific mirror 8 to a specific output port 6.
  • the mirror 8 reflects light of a specific frequency.
  • Each of the plurality of mirrors 8 reflects light having a specific frequency.
  • the switch 4 With the optical element 7 and the mirror 8, the switch 4 outputs the signal light of a specific frequency input from the specific input port 5 to the specific output port 6.
  • the signal light output from the output port 6 may include signal light having a plurality of frequencies.
  • the switch 4 in FIG. 1 selects the signal light by the optical element 7 and the mirror 8, but the signal light may be selected by another method.
  • An optical amplifier 1, an optical combiner 3, and a plurality of transponders 2 are connected to each input port 5, respectively.
  • Each of the plurality of transponders 2 outputs signal light to the optical combiner 3.
  • the optical combiner 3 multiplexes a plurality of signal lights.
  • the optical combiner 3 performs wavelength division multiplexing of the plurality of signal lights. That is, the optical combiner 3 combines a plurality of signal lights.
  • the optical combiner 3 outputs the combined signal light to the optical amplifier 1.
  • the optical amplifier 1 amplifies the combined signal light.
  • the optical amplifier 1 amplifies a plurality of signal lights having different frequencies.
  • Each of the plurality of optical amplifiers 1 amplifies the combined light of the signal lights from the plurality of transponders 2.
  • the plurality of optical amplifiers 1 each output signal light to the switch 4.
  • the switch 4 selects and outputs an arbitrary signal light from a plurality of combined lights.
  • the switch 4 can be selected for each output unit of each optical amplifier 1.
  • the switch 4 can be selected from the output signal light of each optical amplifier 1 in units of signal light of an arbitrary frequency.
  • the switch 4 can select the signal light in units of the output signal light of the transponder 2.
  • the switch 4 multiplexes and outputs the selected signal light.
  • the switch 4 selects signal lights having different frequencies, thereby performing wavelength division multiplexing and outputting a plurality of signal lights.
  • the optical transmission system 10 inputs a plurality of signal lights via the transponder 2, selects and multiplexes arbitrary signal lights, and outputs them.
  • the optical combiner 3 is used to multiplex the signal light.
  • the optical amplifier 1 is used to compensate for the decrease in the light intensity of the signal light when transmitting, multiplexing, switching (selecting) the signal light in the optical transmission system 10.
  • the switch 4 has one output port 6, but the switch 4 can include a plurality of output ports 6. By doing so, the optical transmission system 10 can output light obtained by multiplexing different signal lights from the respective output ports 6.
  • the switch 4 outputs the signal light input to the specific input port 5 to the specific output port 6. At that time, light may leak into the switch 4 to a port other than the desired port. As a result, for example, light may be output from the input port 5.
  • the optical amplifier 1 needs to operate normally even when it receives the light output from the input port 5.
  • FIG. 2 is a configuration diagram of the optical amplifier 1 according to the first embodiment.
  • the optical amplifier 1 according to the first embodiment photoamplifies the signal light. However, when the output fiber is disconnected from the optical amplifier 1, the optical amplifier 1 stops the optical amplification of the signal light.
  • the optical amplifier 1 includes a drive unit 20, an optical amplifier unit 30, and a detection unit 40.
  • the optical amplifier 1 may include a holding unit 50, an input end 51, and an output end 52.
  • the input end 51 is an end point for inputting signal light to the optical amplifier 1.
  • the input end 51 is, for example, a connector.
  • An optical fiber or the like for inputting signal light is connected to the input end 51.
  • the output end 52 is an end point for outputting signal light from the optical amplifier 1.
  • the output end 52 is, for example, a connector.
  • An optical fiber or the like for outputting signal light is connected to the output terminal 52.
  • the light output from the output end 52 is defined as the output light.
  • Light whose propagation direction is opposite to that of output light is defined as return light.
  • the return light has a propagation direction opposite to that of the output light toward the output end 52.
  • the return light is light that goes from the output terminal 52 into the optical amplifier 1.
  • the holding unit 50 holds the identification information.
  • the identification information is information regarding an identification signal that identifies the optical amplifier 1.
  • the identification information is information necessary for generating an identification signal.
  • the identification information is, for example, a pulse train.
  • the identification information is, for example, a frequency for modulation.
  • the identification signal is a signal that can identify each optical amplifier 1.
  • the signal light is modulated by the identification signal and output from the optical amplifier 1.
  • Each optical amplifier 1 outputs different identification signals from each other.
  • the identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave having a certain frequency. In this case, the pulse trains of each optical amplifier 1 are different from each other.
  • the identification signal is a signal obtained by carrying pulse train information on a carrier wave having a frequency different from that of the signal light.
  • the carrier frequency of each identification signal may be the same.
  • the identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave of an arbitrary frequency.
  • the carrier frequencies of the identification signals of each optical amplifier 1 are different from each other.
  • the identification signal is a signal obtained by carrying pulse train information on a carrier wave having a frequency different from that of the signal light.
  • the identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave of an arbitrary frequency. In this case, the combination of the carrier frequency and the pulse train of the identification signal of each optical amplifier 1 is different from each other.
  • the drive unit 20 outputs excitation light.
  • the excitation light is used to photoamplify the signal light.
  • the drive unit 20 outputs the signal light and the excitation light to the optical amplifier unit 30.
  • the drive unit 20 includes an excitation light source 24.
  • the drive unit 20 may include an optical coupler 21, a light receiving element 22, and a drive circuit 23.
  • optical coupler 21 branches the light.
  • the optical coupler 21 outputs the branched light to the optical amplification unit 30 and the light receiving element 22.
  • Light receiving element 22 The light receiving element 22 detects light. The light receiving element 22 outputs the light detection status.
  • Excitation light source 24 outputs excitation light.
  • the excitation light source 24 can adjust the output power of the excitation light.
  • the excitation light source 24 may output an optical signal other than the excitation light.
  • the drive circuit 23 controls the excitation light source 24.
  • the drive circuit 23 instructs the excitation light source 24 to output the excitation light.
  • the drive circuit 23 instructs the excitation light source 24 to output an identification signal.
  • the optical amplification unit 30 photoamplifies the signal light.
  • the optical amplification unit 30 photoamplifies the signal light by using the excitation light.
  • the optical amplification unit 30 may include an amplification fiber 31 and an isolator 32.
  • the amplification fiber 31 photoamplifies the signal light.
  • the amplification fiber 31 is, for example, an erbium-added optical fiber (EDF).
  • EDF erbium-added optical fiber
  • the signal light branched by the optical coupler 21 and the excitation light output from the excitation light source 24 are input to the amplification fiber 31.
  • the amplification fiber 31 photoamplifies the signal light by the excitation light. As the optical power of the excitation light input to the amplification fiber 31 increases, the degree of optical amplification of the signal light also increases.
  • the isolator 32 transmits light in one direction.
  • the isolator 32 passes the light output from the amplification fiber 31.
  • the isolator 32 blocks light in the direction from the detection unit 40 to the amplification fiber 31.
  • the detection unit 40 detects the return light of the signal light.
  • the detection unit 40 includes a comparison circuit 44.
  • the detection unit 40 may include an optical coupler 41 and light receiving elements 42 and 43.
  • the optical coupler 41 branches the light.
  • the optical coupler 41 branches the return light of the output light of the optical amplification unit 30. That is, the optical coupler 41 branches the signal light from the direction of the output end 52.
  • the optical coupler 41 outputs signal light from the direction of the isolator 32 to the output terminal 52.
  • the optical coupler 41 may branch the signal light from the direction of the isolator 32.
  • Light receiving elements 42, 43 >> The light receiving elements 42 and 43 detect light.
  • the light receiving elements 42 and 43 output the light detection status.
  • the light receiving element 42 detects the return light from the direction of the output end 52.
  • the light receiving element 43 detects the signal light from the direction of the isolator 32.
  • the comparison circuit 44 detects whether the return light includes the identification signal of the self-optical amplifier 1.
  • the comparison circuit 44 compares the identification signal included in the return light received by the light receiving element 42 with the identification signal assumed from the identification information.
  • the comparison circuit 44 instructs the drive unit 20 to perform the eye-safe function.
  • the signal light is input to the optical amplifier 1 from the input terminal 51.
  • the signal light is a signal light having one wavelength or a signal light including a plurality of wavelengths.
  • the signal light is output to the drive unit 20.
  • the signal light output from the input end 51 is input to the optical coupler 21.
  • the optical coupler 21 branches the signal light and outputs it to the optical amplification unit 30 and the light receiving element 22.
  • the light receiving element 22 detects the light level of the signal light and notifies the drive circuit 23.
  • the drive circuit 23 detects the presence or absence of signal light from the light level notified from the light receiving element 22. When there is an input of signal light to the light receiving element 22, the drive circuit 23 instructs the excitation light source 24 to increase the output of the excitation light. When there is no signal light input to the light receiving element 22, the drive circuit 23 instructs the excitation light source 24 to reduce the output of the excitation light.
  • the drive circuit 23 acquires identification information from the holding unit 50.
  • the drive circuit 23 generates an identification signal from the identification information.
  • the identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave having a certain frequency.
  • the drive circuit 23 outputs the identification signal to the excitation light source 24.
  • the drive circuit 23 instructs the excitation light source 24 to increase the output of the excitation light. That is, when the optical amplifier 1 has an input of signal light, the output of the excitation light is increased to amplify the signal light.
  • the drive circuit 23 adjusts the output level of the excitation light for the signal light output level adjustment and the eye-safe function. This operation will be described later.
  • the excitation light source 24 outputs excitation light at the output level instructed by the drive circuit 23.
  • the excitation light source 24 outputs excitation light modulated by an identification signal input from the drive circuit 23.
  • the excitation light is amplitude modulated by the identification signal.
  • the frequency of the identification signal is different from the frequency of the signal light.
  • the modulation of the excitation light is a change in the amplification amount of 10% or less of the amplification amount by the optical amplifier.
  • the excitation light output from the excitation light source 24 is combined with the signal light output from the optical coupler 21 and input to the optical amplification unit 30.
  • the excitation light and the signal light modulated by the identification signal are input to the amplification fiber 31.
  • the amplification fiber 31 photoamplifies the signal light according to the light level of the excitation light.
  • the amplification fiber 31 outputs signal light modulated by the identification signal. For example, the signal light is amplitude modulated by the identification signal.
  • the amplification fiber 31 outputs light to the isolator 32.
  • the isolator 32 allows light from the direction of the amplification fiber 31 to pass through.
  • the isolator 32 blocks light from the direction of the detection unit 40.
  • the isolator 32 passes the light photo-amplified by the amplification fiber 31.
  • the isolator 32 blocks the light input to the amplification fiber 31.
  • the isolator 32 blocks light from the detection unit 40 in the direction of the amplification fiber 31.
  • the isolator 32 outputs light to the detection unit 40.
  • the detection unit 40 outputs light to the optical coupler 41.
  • the optical coupler 41 branches the light.
  • the optical coupler 41 outputs the light from the optical amplification unit 30 to the light receiving element 43 and the output terminal 52.
  • the output end 52 outputs the light from the optical coupler 41.
  • the optical amplifier 1 outputs signal light as output light from the output terminal 52.
  • the light receiving element 43 detects the light from the optical amplifier unit 30.
  • the light receiving element 43 detects the light output from the optical amplifier unit 30. When the light receiving element 43 detects light, it outputs the detection status.
  • the light receiving element 43 outputs the detection status of the output light.
  • the output light is output from the output end 52 to the optical fiber.
  • the optical fiber is not attached to the output end 52, Fresnel reflection occurs at the output end 52, and the reflected light of the output light goes in the direction of the optical coupler 41. Further, the light input from the outside of the optical amplifier 1 to the output terminal 52 is sent to the optical coupler 41.
  • Return light is light whose propagation direction is opposite to that of the output light output from the output end 52. Therefore, the return light includes the reflected light of the output light and the light input from the outside to the output terminal 52.
  • the light directed from the output terminal 52 into the optical amplifier 1 is referred to as return light.
  • the optical coupler 41 branches the return light from the output terminal 52 and outputs it to the isolator 32 and the light receiving element 42.
  • the isolator 32 blocks the return light.
  • the light receiving element 42 detects the return light. When the light receiving element 42 detects the light, it notifies the comparison circuit 44 of the detection status.
  • the comparison circuit 44 acquires identification information from the holding unit 50.
  • the comparison circuit 44 recognizes the identification signal of the self-optical amplifier 1 from the identification information.
  • the comparison circuit 44 confirms whether the return light detected by the light receiving element 42 includes the identification signal of the self-optical amplifier 1. When the return light includes the identification signal of the self-optical amplifier 1, the comparison circuit 44 determines that the optical fiber is not mounted on the output terminal 52.
  • the comparison circuit 44 activates the eye safe function.
  • the iSafe function is activated by the following procedure.
  • the comparison circuit 44 controls the drive unit 20 to lower the output level of the excitation light.
  • the drive circuit 23 in the drive unit 20 instructs the excitation light source 24 to lower the output level of the excitation light.
  • the optical amplification unit 30 does not perform optical amplification, and the light level of the output light is lowered. In this way, the eye-safe function is implemented.
  • the operation in the optical amplifier 1 is as follows. Reflected light is generated at the output end 52.
  • the optical coupler 41 outputs the reflected light to the light receiving element 42.
  • the comparison circuit 44 activates the eye-safe function when the identification signal of the self-optical amplifier 1 is included in the reflected light detected by the light receiving element 42.
  • the operation in the optical amplifier 1 is as follows. Return light is generated at the output terminal 52.
  • the optical coupler 41 outputs the return light to the light receiving element 42.
  • the comparison circuit 44 cannot detect the identification signal of the self-optical amplifier 1 in the return light detected by the light receiving element 42. Therefore, the comparison circuit 44 does not activate the eye-safe function.
  • the optical fiber omission is determined based on the presence or absence of the identification signal of the self-optical amplifier 1 in the return light, the accuracy of the optical fiber omission can be improved. And it is possible to avoid unnecessary activation of the eye safe function.
  • the optical level of the reflected light is sufficiently smaller than that in the case where the optical fiber is pulled out at the output terminal 52. Therefore, when the optical level of the identification signal of the self-optical amplifier 1 of the return light is sufficiently smaller than the optical level of the identification signal of the output light, it can be determined that the optical fiber is not dropped.
  • the optical coupler 41 branches the light from the optical amplification unit 30 and outputs the light to the output terminal 52 and the light receiving element 43. Therefore, the light receiving element 43 detects light corresponding to the output light. On the other hand, the light receiving element 42 detects the return light. Therefore, the comparison circuit 44 can recognize the reflectance of the output light from the detection status of the light receiving elements 42 and 43.
  • the comparison circuit 44 can detect the identification signal of the self-optical amplifier 1 in the light detected by the light receiving element 43.
  • the light level of the identification signal corresponds to the output level of the output light. Further, when the comparison circuit 44 detects the identification signal of the self-optical amplifier 1 in the light detected by the light receiving element 42, the comparison circuit 44 can recognize the light level of the reflected light by the light level of the identification signal. Therefore, the comparison circuit 44 can recognize the reflectance of the identification signal by comparing the light intensity of the identification signal detected by the light receiving element 43 and the light receiving element 42.
  • the comparison circuit 44 determines that the optical fiber is attached and does not perform the eye-safe function.
  • the comparison circuit 44 determines that the optical fiber is not mounted and performs the eye-safe function. This is a corresponding example in consideration of the fact that a slight amount of reflected light is generated even when an optical fiber is attached to the output end 52.
  • the comparison circuit 44 of the detection unit 40 uses the output level of the excitation light. Do not lower.
  • the predetermined ratio is smaller than the optical level ratio of the identification signal when the optical fiber is disconnected.
  • the level of light detected by the light receiving element 22 corresponds to the light level of the signal light before light amplification
  • the light level of the signal light detected by the light receiving element 43 corresponds to the light level of the signal light after light amplification. Therefore, the drive circuit 23 can recognize the degree of light amplification in the optical amplification unit 30 by comparing the level of light detected by the light receiving element 22 with the level of light detected by the light receiving element 43. When the degree of optical amplification is insufficient, the drive circuit 23 instructs the excitation light source 24 to increase the output level of the excitation light. In this way, the optical amplifier 1 can adjust the output level of the signal light by adjusting the output level of the excitation light.
  • the optical amplifier 1 of FIG. 1 photoamplifies the signal light by the excitation light modulated by the identification signal. Then, the optical amplification unit 30 outputs the signal light modulated by the identification signal. However, the optical amplifier 1 may multiplex and output the identification signal and the signal light.
  • the excitation light source 24 outputs the excitation light and the identification signal
  • the optical amplification unit 30 outputs the identification signal and the signal light. Further, the optical amplifier 1 may multiplex the signal light after optical amplification and the identification signal. That is, the identification signal may be multiplexed with respect to the signal light output from the optical amplification unit 30. In this case, the identification signal may be generated by a component other than the drive circuit 23.
  • FIG. 3 is an explanatory diagram showing an example of the operation of the optical transmission system 10.
  • each component is the same as in FIG. 3.
  • FIG. 1 light of a specific frequency input from the top input port 5 is reflected by the mirror 8 and output from the bottom output port 6. Similar to FIG. 1, in FIG. 3, light of a specific frequency (solid arrow) input from the top input port 5 is reflected by the mirror 8 and output from the bottom output port 6. At this time, light may leak into the switch 4 to a port other than the desired port. In FIG. 3, unintentionally, light of a specific frequency (dotted arrow) input from the second input port 5 from the top is reflected by the mirror 8 and output to the bottom input port 5.
  • the optical amplifier 1 connected to the bottom input port 5 receives light of a specific frequency input from the second input port 5 from the top from the output terminal 52.
  • the light input from the output terminal 52 is detected by the light receiving element 42. Since the light detected by the light receiving element 42 does not include the identification signal output by the self-optical amplifier 1, the comparison circuit 44 determines that the optical fiber is not disconnected and does not activate the eye safe function. When a conventional optical amplifier is used, the eye safe function is activated depending on the light level of the light received from the input port 5.
  • FIG. 4 is an explanatory diagram showing another example of the operation of the optical transmission system 10.
  • each component is the same as in FIGS. 1 and 3.
  • the identification signal output by the optical amplifiers 1a to 1m will be described.
  • the identification signal is, for example, a signal obtained by carrying information of a 4-bit pulse train on a carrier wave having a certain frequency.
  • the optical amplifiers 1a to 1m output different pulse trains.
  • the optical amplifier 1b outputs signal light modulated by an identification signal including a 4-bit 1010 pulse train.
  • the signal light from the optical amplifier 1b is input to the input port 5b of the switch 4.
  • the optical amplifier 1 m outputs signal light modulated by an identification signal including a 4-bit 1110 pulse train.
  • the signal light from the optical amplifier 1 m is input to the input port 5 m of the switch 4.
  • the light receiving element 42 detects the signal light including the pulse train 1010 input from the output terminal 52. Since the light detected by the light receiving element 42 does not include the identification signal (pulse train 1110) output by the optical amplifier 1m, the comparison circuit 44 determines that the optical fiber is not disconnected and does not activate the eye safe function.
  • the signal light that the optical amplifier 1 m tries to output is reflected by the output end 52 and detected by the light receiving element 42.
  • the comparison circuit 44 detects that the light detected by the light receiving element 42 includes the pulse train 1110, determines that the optical fiber is disconnected, and activates the eye safe function. In this way, even when a phenomenon in which light leaks to a port other than the desired port occurs in the switch 4, the accuracy of determining whether or not the optical fiber is disconnected can be improved.
  • FIG. 5 is a flowchart showing an example of the processing flow of the optical amplifier 1. As shown in FIG. 4, this is an example of a processing flow assuming that the output light of the optical amplifier 1b is input to the optical amplifier 1m via the switch 4 in the optical transmission system 10. In FIG. 4, it is assumed that each optical amplifier 1 outputs a different identification signal, but in this flowchart, it corresponds to the case where another optical amplifier 1 outputs the same identification signal.
  • step S1 signal light is input to the input terminal 51 of the optical amplifier 1.
  • step S2 signal light is input to the input terminal 51 of the optical amplifier 1.
  • step S2 the light receiving element 43 detects the return light, and the comparison circuit 44 confirms whether the return light includes the identification signal of the self-optical amplifier 1.
  • the return light includes light reflected by the output light at the output terminal 52 and light input from the outside of the optical amplifier 1 via the output terminal 52.
  • the identification signal is a signal obtained by carrying information of an arbitrary pulse train on a carrier wave having a specific frequency. Therefore, for example, it is an identification signal in which the frequency information of the identification information held by the holding unit 50 matches.
  • step S3 the drive circuit 23 uses the identification information of the holding unit 50 to generate an identification signal and outputs it to the excitation light source 24. Then, the process proceeds to step S5.
  • step S4 since there is a possibility that the identification signal from another optical amplifier 1 operating in the system is received, the identification signal included in the return light is investigated by the comparison circuit 44.
  • the drive circuit 23 When the identification signal generated by using the identification information of the holding unit 50 and the identification signal of the return light are different, the drive circuit 23 generates an identification signal by using the identification information of the holding unit 50 and outputs it to the excitation light source 24. ..
  • the drive circuit 23 changes the identification information of the holding unit 50, generates an identification signal from the changed identification information, and excites. Output to the light source 24.
  • the same identification signal means, for example, the same 4-bit pulse train (for example, 1110). In this case, change the pulse train to a different one.
  • the identification information regarding the generated identification signal is held in the holding unit 50. Then, the process proceeds to step S5.
  • step S5 the optical amplifier 1 starts optical amplification.
  • the drive circuit 23 instructs the excitation light source 24 to increase the output of the excitation light.
  • the signal light is photo-amplified according to the light level of the excitation light.
  • the light-amplified signal light is modulated by the identification signal and output from the optical amplifier 1 as output light. Then, the process proceeds to step S6.
  • step S6 it is confirmed whether the return light contains the same identification signal as the identification signal generated by the drive circuit 23. That is, the comparison circuit 44 confirms whether the light detected by the light receiving element 43 includes an identification signal generated by using the identification information of the holding unit 50.
  • step S6 If the return light does not contain the same identification signal, the process returns to step S6. That is, it keeps checking whether the return light contains the same identification signal. If the return light contains the same identification signal, the process proceeds to step S7.
  • step S7 the optical amplifier 1 interrupts the optical amplification. This is because the comparison circuit 44 has detected the reflected light and has determined that the optical fiber may not be attached.
  • the drive circuit 23 instructs the excitation light source 24 to reduce the output of the excitation light. Since the light level of the excitation light is lowered in the amplification fiber 31, the signal light is not photoamplified. In this way, the eye safe function is activated. Proceed to step S8.
  • step S6 When it is determined to be yes in step S6, it is considered that the optical fiber is not mounted on the output terminal 52 and the other optical amplifier 1 outputs the same identification signal. Therefore, it is confirmed whether the other optical amplifier 1 outputs the same identification signal.
  • the confirmation method is to investigate whether the identification signal of the return light changes by changing the identification signal to be output.
  • step S8 the optical amplifier 1 changes the identification signal to be output.
  • the drive circuit 23 changes the identification information of the holding unit 50, generates an identification signal from the changed identification information, and outputs the identification signal to the excitation light source 24. Proceed to step S9.
  • step S9 it is confirmed whether the return light contains the same identification signal as the identification signal generated by the drive circuit 23. That is, the comparison circuit 44 confirms whether the light detected by the light receiving element 43 includes an identification signal generated by using the identification information of the holding unit 50.
  • step S5 it is determined that the reflected light due to the loss of the optical fiber is not generated, and the optical amplification is restarted. If the return light contains the same identification signal, the process proceeds to step S10.
  • step S10 wait for the return light containing the same identification signal to disappear. That is, it waits until the same identification signal as the identification signal generated by the drive circuit 23 is not included in the return light detected by the light receiving element 43. This determines that the reflected light is detected without the optical fiber being attached, and interrupts the optical amplification until the reflected light disappears. Then, when the return light containing the same identification signal is no longer detected, the process proceeds to step S5. That is, it is determined that the reflected light due to the loss of the optical fiber is not generated, and the optical amplification is restarted.
  • FIG. 6 is a configuration diagram showing an optical transmission system 11 according to a modification 1 of the first embodiment.
  • the optical transmission system 11 is an optical transmission system 10 to which a management device 60 is added. Since the other components are the same as those in FIG. 1, the description thereof will be omitted.
  • the optical transmission system 11 includes a switch 4 and a management device 60.
  • the optical transmission system 11 can include a plurality of transponders 2, a plurality of optical combiners 3, and a plurality of optical amplifiers 1.
  • Management device 60 notifies the optical amplifier 1 of the identification information.
  • the management device 60 includes, for example, a table 61.
  • the management device 60 holds the identification information to be notified to each optical amplifier 1 in the table 61.
  • optical transmission system 11 ⁇ Operation of optical transmission system 11> Next, the operation of the optical transmission system 11 will be described. Since it is the same as the optical transmission system 10 except for the operation related to the management device 60, the description thereof will be omitted.
  • the management device 60 recognizes the optical amplifier 1 included in the optical transmission system 11.
  • the management device 60 holds identification information for the number of optical amplifiers 1 in the table 61.
  • the identification information in the table 61 is different information.
  • the management device 60 notifies each optical amplifier 1 of different identification information.
  • the dotted arrow from the management device 60 to each optical amplifier 1 indicates notification of identification information.
  • the optical amplifier 1 When the optical amplifier 1 is notified of the identification information by the management device 60, the optical amplifier 1 stores the identification information in the holding unit 50. During operation, the optical amplifier 1 generates and outputs an identification signal from the identification information of the holding unit 50. Each optical amplifier 1 holds different identification information in the holding unit 50. Each optical amplifier 1 generates and outputs different identification signals.
  • each optical amplifier 1 outputs a different identification signal.
  • the optical amplifier 1 can recognize the signal light of the other optical amplifier 1 and does not erroneously recognize that the optical fiber is disconnected.
  • step S2 The processing flowchart of the optical amplifier 1 according to the first modification of the first embodiment is changed from the flowchart of FIG. 5 in the next step. Steps S2, S4, S8, S9 are eliminated.
  • the process proceeds from step S1 to step S3.
  • the process proceeds from step S7 to step S10.

Abstract

To improve the detection accuracy of output fiber detachment for eye-safe function operation, this light amplifier for amplifying signal light is provided with: a drive unit in which excitation light for light amplification is modulated by an identification signal that identifies the light amplifier; a light amplification unit for amplifying the signal light through the use of the excitation light outputted from the drive unit, and outputting the amplified signal light as the output light to the outside; and a detection unit for detecting return light that propagates in a direction opposite to that of the output light, and controlling the output level of the excitation light so as to lower the output level when the identification signal of the light amplifier is included in the return light.

Description

光増幅器、光伝送システム、および光増幅方法Optical amplifiers, optical transmission systems, and optical amplification methods
　本開示は、光増幅器に関する。 This disclosure relates to an optical amplifier.
　光増幅器は、入力された信号光の光レベルを増幅して出力する。その際、光増幅器は高出力の光を発生させる。光増幅器から出力ファイバが外れた場合に高出力の光から人の目を保護するために、光増幅器は光の出力を低下させるアイセーフ機能を備えていることがある。光増幅器の出力端から出力ファイバが外れると、出力端が開放となり、一部の光が出力端で反射して光増幅器に戻る。そのため、光増幅器内へ戻ってくる戻り光を検出することで、光増幅器は光ファイバが外れたことを認識することが可能である。 The optical amplifier amplifies the optical level of the input signal light and outputs it. At that time, the optical amplifier generates high-power light. In order to protect the human eye from high-power light when the output fiber is disconnected from the optical amplifier, the optical amplifier may have an eye-safe function that reduces the light output. When the output fiber is disconnected from the output end of the optical amplifier, the output end is opened, and some light is reflected at the output end and returned to the optical amplifier. Therefore, by detecting the return light returning into the optical amplifier, the optical amplifier can recognize that the optical fiber has come off.
　例えば、特許文献１に記載の光増幅器は、入力端から入力された信号光を光増幅して出力端から出力する光増幅部と、出力端から自機に入力された反射光または／および戻り光からなる光を分岐する分岐部と、分岐部により分岐された光を受光して光レベルを検出する受光素子と、受光素子により検出された光レベルが予め設定した第１の閾値以上である場合に、光増幅部の光増幅量を減少させる制御回路とを備えている。 For example, the optical amplifier described in Patent Document 1 has an optical amplifier unit that photoamplifies signal light input from an input end and outputs it from an output end, and reflected light and / or return light input to the own machine from the output end. The branch portion that branches the light composed of light, the light receiving element that receives the light branched by the branch portion and detects the light level, and the light level detected by the light receiving element are equal to or higher than a preset first threshold value. In some cases, it is provided with a control circuit that reduces the amount of light amplification in the light amplification unit.
国際公開公報２０１１／１２９１０１号（第３頁０００２～００１１、図１）International Publication No. 2011/129101 (Page 3, 0002-0011, FIG. 1)
　光増幅器内へ戻ってくる戻り光の発生要因は、光増幅器から出力される出力光の出力端での反射の他に、光増幅器の出力端に接続される外部装置からの光の入力がある。例えば、外部装置内で所望の出力端以外に光が漏れてしまう場合に、光増幅器内への戻り光が発生する。従来の光増幅器では、戻り光の光レベルで出力ファイバ外れの判断を行っていたため、外部装置から入力される戻り光を出力ファイバ外れと誤認識する可能性があるという課題があった。 In addition to the reflection of the output light output from the optical amplifier at the output end, the cause of the return light returning into the optical amplifier is the input of light from an external device connected to the output end of the optical amplifier. .. For example, when light leaks to other than the desired output end in the external device, return light to the inside of the optical amplifier is generated. In the conventional optical amplifier, since the output fiber disconnection is determined based on the light level of the return light, there is a problem that the return light input from the external device may be erroneously recognized as the output fiber disconnection.
　上述のような課題を解決するためになされたもので、出力ファイバ外れの検出精度を向上することを目的とする。 It was made to solve the above-mentioned problems, and aims to improve the detection accuracy of the output fiber disconnection.
　信号光を光増幅する光増幅器は、光増幅器を識別する識別信号によって光増幅用の励起光を変調する駆動部と、駆動部から出力される励起光を用いて信号光を光増幅し出力光として外部に出力する光増幅部と、出力光と伝搬方向が逆となる戻り光を検出し戻り光に自光増幅器の識別信号が含まれている場合に励起光の出力レベルを下げる制御を行う検出部とを備える。 An optical amplifier that photoamplifies signal light has a drive unit that modulates the excitation light for optical amplification with an identification signal that identifies the optical amplifier, and an excitation light that is output from the drive unit to photoamplify the signal light and output light. It detects the optical amplifier that outputs to the outside and the return light whose propagation direction is opposite to that of the output light, and controls to lower the output level of the excitation light when the return light contains the identification signal of the self-optical amplifier. It is equipped with a detection unit.
　出力ファイバ外れの検出精度を向上することができる。 It is possible to improve the detection accuracy of output fiber disconnection.
実施の形態１に係る光増幅器１を光伝送システムに組み込んだ構成図である。It is a block diagram which incorporated the optical amplifier 1 which concerns on Embodiment 1 into an optical transmission system. 実施の形態１に係る光増幅器１の構成図である。It is a block diagram of the optical amplifier 1 which concerns on Embodiment 1. FIG. 光伝送システム１０の動作の一例を示す説明図である。It is explanatory drawing which shows an example of the operation of an optical transmission system 10. 光伝送システム１０の動作の他の例を示す説明図である。It is explanatory drawing which shows another example of operation of an optical transmission system 10. 光増幅器１の処理フローの一例を示すフローチャートである。It is a flowchart which shows an example of the processing flow of an optical amplifier 1. 実施の形態１の変形例１に係る光伝送システム１１を示す構成図である。It is a block diagram which shows the optical transmission system 11 which concerns on the modification 1 of Embodiment 1. FIG.
実施の形態１．
　光増幅器１は、信号光を光増幅する。例えば、光増幅器１は、入力する信号光を光増幅して出力する。 Embodiment 1.
The optical amplifier 1 photoamplifies the signal light. For example, the optical amplifier 1 photoamplifies and outputs the input signal light.
　光増幅器は様々な光伝送システムに組み込まれている。「多方路」に光伝送が行える通信システム、すなわち多方路光伝送システムなどにも光増幅器が用いられている。多方路光伝送システムには、例えば、ＷＤＭ（Ｗａｖｅｌｅｎｇｔｈ　Ｄｉｖｉｓｉｏｎ　Ｍｕｌｔｉｐｌｅｘｉｎｇ）システム、ＲＯＡＤＭ（Ｒｅｃｏｎｆｉｇｕｒａｂｌｅ　Ｏｐｔｉｃａｌ　Ａｄｄ　Ｄｒｏｐ　Ｍｕｌｔｉｐｌｅｘｅｒ）システム、及びＯＸＣ（Ｏｐｔｉｃａｌ　Ｃｒｏｓｓ　Ｃｏｎｎｅｃｔ）システムなどがある。多方路光伝送システムなどのような光伝送システムでは、信号光を光増幅するために、光増幅器が用いられる。 Optical amplifiers are incorporated in various optical transmission systems. Optical amplifiers are also used in communication systems capable of optical transmission in "multi-way", that is, multi-way optical transmission systems and the like. The multi-way optical transmission system includes, for example, a WDM (Wavelength Division Multiplexing) system, a ROADM (Reconfigurable Optical Add Multiplexer) system, and an OXC (Optical Cross Connect) system. In an optical transmission system such as a multi-way optical transmission system, an optical amplifier is used to optically amplify the signal light.
　以下、実施の形態１に係る光増幅器１について、図面を用いて詳細に説明する。なお、以下の実施の形態１は、一具体例を示すものである。したがって、各構成要素の形状、配置および材料などは一例であり、限定する趣旨はない。また、各図は模式図であり、厳密に図示されたものではない。また、各図において、同じ構成要素については同じ符号を付している。 Hereinafter, the optical amplifier 1 according to the first embodiment will be described in detail with reference to the drawings. The following first embodiment shows a specific example. Therefore, the shape, arrangement, material, etc. of each component are examples and are not intended to be limited. Moreover, each figure is a schematic view and is not exactly illustrated. Further, in each figure, the same components are designated by the same reference numerals.
　図１は、実施の形態１に係る光増幅器１を光伝送システム１０に組み込んだ場合の一例を示す構成図である。光伝送システム１０は、例えば、複数の信号光から任意の信号光を選択して出力する。光伝送システム１０は、複数の任意の信号光を選択し、波長多重して出力する。 FIG. 1 is a configuration diagram showing an example of a case where the optical amplifier 1 according to the first embodiment is incorporated in the optical transmission system 10. The optical transmission system 10 selects and outputs an arbitrary signal light from, for example, a plurality of signal lights. The optical transmission system 10 selects a plurality of arbitrary signal lights, multiplexes the wavelengths, and outputs the light.
＜光伝送システム１０の構成＞
　光伝送システム１０は、スイッチ４、光増幅器１を備える。光伝送システム１０は、トランスポンダ２、および光合波器３を備えることができる。 <Configuration of optical transmission system 10>
The optical transmission system 10 includes a switch 4 and an optical amplifier 1. The optical transmission system 10 can include a transponder 2 and an optical combiner 3.
≪トランスポンダ２≫
　トランスポンダ２は、信号光を出力する。トランスポンダ２は、例えば、特定波長の信号光に変換する。トランスポンダ２は、例えば、インタフェースモジュールである。 ≪Transponder 2≫
The transponder 2 outputs a signal light. The transponder 2 converts, for example, into signal light having a specific wavelength. The transponder 2 is, for example, an interface module.
≪光合波器３≫
　光合波器３は、複数の信号光を多重する。光合波器３は、例えば、波長の異なる信号光を多重する。 ≪Optical combiner 3≫
The optical combiner 3 multiplexes a plurality of signal lights. The optical combiner 3 multiplexes signal lights having different wavelengths, for example.
≪光増幅器１≫
　光増幅器１は、信号光を光増幅する。光増幅器１は、例えば、多重された信号光を光増幅する。 ≪Optical amplifier 1≫
The optical amplifier 1 photoamplifies the signal light. The optical amplifier 1 photoamplifies, for example, the multiplexed signal light.
≪スイッチ４≫
　スイッチ４は、入力される複数の信号光から、任意の信号光を選択して出力する。スイッチ４は、例えば、選択した信号光を多重して出力する。スイッチ４は、例えば、ＷＳＳ（Wａｖｅｌｅｎｇｔｈ　Ｓｅｌｅｃｔｉｖｅ　Ｓｗｉｔｃｈ）、ＷＤＭ、ＲＯＡＤＭ、ＯＸＣなどである。 ≪Switch 4≫
The switch 4 selects and outputs an arbitrary signal light from a plurality of input signal lights. The switch 4 multiplexes and outputs, for example, the selected signal light. The switch 4 is, for example, WSS (Wavelength Selective Switch), WDM, ROADM, OXC, or the like.
　スイッチ４は、入力ポート５および出力ポート６を備える。スイッチ４は、複数の入力ポート５を備えてもよい。スイッチ４は、複数の出力ポート６を備えてもよい。スイッチ４は、光学素子７およびミラー８を備えてもよい。 The switch 4 includes an input port 5 and an output port 6. The switch 4 may include a plurality of input ports 5. The switch 4 may include a plurality of output ports 6. The switch 4 may include an optical element 7 and a mirror 8.
　光学素子７は、特定の周波数の光を特定の入力ポート５から特定のミラー８へ導く。また、光学素子７は、特定の周波数の光を特定のミラー８から特定の出力ポート６へ導く。ミラー８は、特定の周波数の光を反射する。複数のミラー８は、それぞれ特定の周波数の光を反射する。 The optical element 7 guides light of a specific frequency from a specific input port 5 to a specific mirror 8. Further, the optical element 7 guides light of a specific frequency from a specific mirror 8 to a specific output port 6. The mirror 8 reflects light of a specific frequency. Each of the plurality of mirrors 8 reflects light having a specific frequency.
　光学素子７およびミラー８によって、スイッチ４は特定の入力ポート５から入力される特定の周波数の信号光を特定の出力ポート６に出力する。出力ポート６より出力される信号光は、複数の周波数の信号光を含んでもよい。図１のスイッチ４は、光学素子７とミラー８によって、信号光の選択を行っているが、他の方法で信号光の選択をしてもよい。 With the optical element 7 and the mirror 8, the switch 4 outputs the signal light of a specific frequency input from the specific input port 5 to the specific output port 6. The signal light output from the output port 6 may include signal light having a plurality of frequencies. The switch 4 in FIG. 1 selects the signal light by the optical element 7 and the mirror 8, but the signal light may be selected by another method.
　各入力ポート５には、それぞれ、光増幅器１、光合波器３、および複数のトランスポンダ２が接続されている。 An optical amplifier 1, an optical combiner 3, and a plurality of transponders 2 are connected to each input port 5, respectively.
＜光伝送システム１０の動作＞
　次に、光伝送システム１０の動作について説明する。 <Operation of optical transmission system 10>
Next, the operation of the optical transmission system 10 will be described.
　複数のトランスポンダ２は、それぞれ光合波器３に信号光を出力する。光合波器３は、複数の信号光を多重する。複数のトランスポンダ２より波長の異なる信号光が出力されると、光合波器３は複数の信号光を波長多重する。つまり光合波器３は、複数の信号光を合波する。 Each of the plurality of transponders 2 outputs signal light to the optical combiner 3. The optical combiner 3 multiplexes a plurality of signal lights. When signal lights having different wavelengths are output from the plurality of transponders 2, the optical combiner 3 performs wavelength division multiplexing of the plurality of signal lights. That is, the optical combiner 3 combines a plurality of signal lights.
　光合波器３は、合波された信号光を光増幅器１に出力する。光増幅器１は、合波された信号光を増幅する。光増幅器１は、複数の異なる周波数の信号光を増幅する。複数の光増幅器１は、それぞれ、複数のトランスポンダ２からの信号光が合波された光を増幅する。 The optical combiner 3 outputs the combined signal light to the optical amplifier 1. The optical amplifier 1 amplifies the combined signal light. The optical amplifier 1 amplifies a plurality of signal lights having different frequencies. Each of the plurality of optical amplifiers 1 amplifies the combined light of the signal lights from the plurality of transponders 2.
　複数の光増幅器１は、それぞれ信号光をスイッチ４に出力する。スイッチ４は、複数の合波された光から、任意の信号光を選択して出力する。スイッチ４は、各光増幅器１の出力単位で選択することができる。スイッチ４は、各光増幅器１の出力信号光の中から、任意周波数の信号光単位で選択することができる。スイッチ４は、トランスポンダ２の出力信号光単位で信号光を選択することができる。スイッチ４は、選択した信号光を多重して出力する。スイッチ４はそれぞれ異なる周波数の信号光を選択することで、複数の信号光を波長多重して出力する。 The plurality of optical amplifiers 1 each output signal light to the switch 4. The switch 4 selects and outputs an arbitrary signal light from a plurality of combined lights. The switch 4 can be selected for each output unit of each optical amplifier 1. The switch 4 can be selected from the output signal light of each optical amplifier 1 in units of signal light of an arbitrary frequency. The switch 4 can select the signal light in units of the output signal light of the transponder 2. The switch 4 multiplexes and outputs the selected signal light. The switch 4 selects signal lights having different frequencies, thereby performing wavelength division multiplexing and outputting a plurality of signal lights.
　このように、光伝送システム１０は、トランスポンダ２を介して、複数の信号光を入力し、任意の信号光を選択・多重して出力する。光伝送システム１０内により多くの信号光を取り入れるために、光合波器３を用いて信号光を多重している。光伝送システム１０内での信号光の伝送、多重、切替（選択）などを行う際の信号光の光強度の低下を補うために、光増幅器１は用いられる。図１では、スイッチ４の出力ポート６は１つであるが、スイッチ４は複数の出力ポート６を備えることができる。こうすることで、光伝送システム１０は、それぞれ異なる信号光を多重した光を、それぞれの出力ポート６から出力することができる。 In this way, the optical transmission system 10 inputs a plurality of signal lights via the transponder 2, selects and multiplexes arbitrary signal lights, and outputs them. In order to take in more signal light in the optical transmission system 10, the optical combiner 3 is used to multiplex the signal light. The optical amplifier 1 is used to compensate for the decrease in the light intensity of the signal light when transmitting, multiplexing, switching (selecting) the signal light in the optical transmission system 10. In FIG. 1, the switch 4 has one output port 6, but the switch 4 can include a plurality of output ports 6. By doing so, the optical transmission system 10 can output light obtained by multiplexing different signal lights from the respective output ports 6.
　スイッチ４は、特定の入力ポート５に入力された信号光を、特定の出力ポート６に出力する。その際、スイッチ４内で所望ポート以外に光が漏れこむことがある。これによって、例えば、入力ポート５から光が出力されることがある。光増幅器１は入力ポート５から出力された光を受信した場合にも正常に動作する必要がある。 The switch 4 outputs the signal light input to the specific input port 5 to the specific output port 6. At that time, light may leak into the switch 4 to a port other than the desired port. As a result, for example, light may be output from the input port 5. The optical amplifier 1 needs to operate normally even when it receives the light output from the input port 5.
　図２は、実施の形態１に係る光増幅器１の構成図である。実施の形態１に係る光増幅器１は、信号光を光増幅する。ただし、光増幅器１から出力ファイバが外れた場合には、光増幅器１は信号光の光増幅を停止する。 FIG. 2 is a configuration diagram of the optical amplifier 1 according to the first embodiment. The optical amplifier 1 according to the first embodiment photoamplifies the signal light. However, when the output fiber is disconnected from the optical amplifier 1, the optical amplifier 1 stops the optical amplification of the signal light.
＜光増幅器１の構成＞
　光増幅器１は、駆動部２０、光増幅部３０、および検出部４０を備える。光増幅器１は、保持部５０、入力端５１、および出力端５２を備えてもよい。 <Configuration of optical amplifier 1>
The optical amplifier 1 includes a drive unit 20, an optical amplifier unit 30, and a detection unit 40. The optical amplifier 1 may include a holding unit 50, an input end 51, and an output end 52.
≪入力端５１≫
　入力端５１は、光増幅器１へ信号光を入力するための端点である。入力端５１は、例えば、コネクタである。信号光を入力するための光ファイバなどが入力端５１に接続される。 ≪Input end 51≫
The input end 51 is an end point for inputting signal light to the optical amplifier 1. The input end 51 is, for example, a connector. An optical fiber or the like for inputting signal light is connected to the input end 51.
≪出力端５２≫
　出力端５２は、光増幅器１から信号光を出力するための端点である。出力端５２は、例えば、コネクタである。信号光を出力するための光ファイバなどが出力端５２に接続される。出力端５２から出力される光を出力光とする。出力光と伝搬方向が逆となる光を戻り光とする。戻り光は、出力端５２に向かう出力光と伝搬方向が逆となる。戻り光は、出力端５２から光増幅器１内へ向かう光である。 ≪Output end 52≫
The output end 52 is an end point for outputting signal light from the optical amplifier 1. The output end 52 is, for example, a connector. An optical fiber or the like for outputting signal light is connected to the output terminal 52. The light output from the output end 52 is defined as the output light. Light whose propagation direction is opposite to that of output light is defined as return light. The return light has a propagation direction opposite to that of the output light toward the output end 52. The return light is light that goes from the output terminal 52 into the optical amplifier 1.
≪保持部５０≫
　保持部５０は、識別情報を保持する。識別情報は、光増幅器１を識別する識別信号に関する情報である。識別情報は、識別信号を生成するために必要な情報である。識別情報は、例えば、パルス列である。識別情報は、例えば、変調用の周波数である。 ≪Holding part 50≫
The holding unit 50 holds the identification information. The identification information is information regarding an identification signal that identifies the optical amplifier 1. The identification information is information necessary for generating an identification signal. The identification information is, for example, a pulse train. The identification information is, for example, a frequency for modulation.
≪識別信号≫
　識別信号は、各光増幅器１を識別できる信号である。信号光は識別信号によって変調されて、光増幅器１から出力される。各光増幅器１は、お互いに異なる識別信号を出力する。識別信号は、例えば、ある周波数の搬送波にパルス列の情報を乗せた信号である。この場合、各光増幅器１のパルス列は、お互いに異なる。識別信号は、信号光の周波数と異なる周波数の搬送波にパルス列の情報を乗せた信号である。各識別信号の搬送波の周波数は同じでもよい。 ≪Identification signal≫
The identification signal is a signal that can identify each optical amplifier 1. The signal light is modulated by the identification signal and output from the optical amplifier 1. Each optical amplifier 1 outputs different identification signals from each other. The identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave having a certain frequency. In this case, the pulse trains of each optical amplifier 1 are different from each other. The identification signal is a signal obtained by carrying pulse train information on a carrier wave having a frequency different from that of the signal light. The carrier frequency of each identification signal may be the same.
　識別信号は、例えば、任意の周波数の搬送波にパルス列の情報を乗せた信号である。各光増幅器１の識別信号の搬送波の周波数は、お互いに異なる。識別信号は、信号光の周波数と異なる周波数の搬送波にパルス列の情報を乗せた信号である。識別信号は、例えば、任意の周波数の搬送波にパルス列の情報を乗せた信号である。この場合、各光増幅器１の識別信号の搬送波の周波数とパルス列との組み合わせは、お互い異なる。 The identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave of an arbitrary frequency. The carrier frequencies of the identification signals of each optical amplifier 1 are different from each other. The identification signal is a signal obtained by carrying pulse train information on a carrier wave having a frequency different from that of the signal light. The identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave of an arbitrary frequency. In this case, the combination of the carrier frequency and the pulse train of the identification signal of each optical amplifier 1 is different from each other.
≪駆動部２０≫
　駆動部２０は、励起光を出力する。励起光は、信号光を光増幅するために用いられる。駆動部２０は、信号光と励起光とを光増幅部３０へ出力する。駆動部２０は、励起光源２４を備える。駆動部２０は、光カプラ２１、受光素子２２、および駆動回路２３を備えてもよい。 << Drive unit 20 >>
The drive unit 20 outputs excitation light. The excitation light is used to photoamplify the signal light. The drive unit 20 outputs the signal light and the excitation light to the optical amplifier unit 30. The drive unit 20 includes an excitation light source 24. The drive unit 20 may include an optical coupler 21, a light receiving element 22, and a drive circuit 23.
≪光カプラ２１≫
　光カプラ２１は、光を分岐する。光カプラ２１は、分岐した光を光増幅部３０と受光素子２２とへ出力する。 ≪Optical coupler 21≫
The optical coupler 21 branches the light. The optical coupler 21 outputs the branched light to the optical amplification unit 30 and the light receiving element 22.
≪受光素子２２≫
　受光素子２２は、光を検知する。受光素子２２は、光の検知状況を出力する。 << Light receiving element 22 >>
The light receiving element 22 detects light. The light receiving element 22 outputs the light detection status.
≪励起光源２４≫
　励起光源２４は、励起光を出力する。励起光源２４は、励起光の出力パワーを調整できる。励起光源２４は、励起光以外の光信号を出力してもよい。 << Excitation light source 24 >>
The excitation light source 24 outputs excitation light. The excitation light source 24 can adjust the output power of the excitation light. The excitation light source 24 may output an optical signal other than the excitation light.
≪駆動回路２３≫
　駆動回路２３は、励起光源２４の制御を行う。駆動回路２３は、励起光源２４に対して、励起光の出力パワーを指示する。駆動回路２３は、励起光源２４に対して、識別信号の出力を指示する。 ≪Drive circuit 23≫
The drive circuit 23 controls the excitation light source 24. The drive circuit 23 instructs the excitation light source 24 to output the excitation light. The drive circuit 23 instructs the excitation light source 24 to output an identification signal.
≪光増幅部３０≫
　光増幅部３０は、信号光を光増幅する。光増幅部３０は、励起光を用いて、信号光を光増幅する。光増幅部３０は、増幅用ファイバ３１、およびアイソレータ３２を備えてもよい。 << Optical amplifier 30 >>
The optical amplification unit 30 photoamplifies the signal light. The optical amplification unit 30 photoamplifies the signal light by using the excitation light. The optical amplification unit 30 may include an amplification fiber 31 and an isolator 32.
≪増幅用ファイバ３１≫
　増幅用ファイバ３１は、信号光を光増幅する。増幅用ファイバ３１は、例えば、エルビウム添加光ファイバ（ＥＤＦ）である。光カプラ２１で分岐した信号光と、励起光源２４から出力される励起光とが、増幅用ファイバ３１に入力される。増幅用ファイバ３１は、励起光により、信号光を光増幅する。増幅用ファイバ３１に入力される励起光の光パワーが大きくなると、信号光の光増幅の度合いも高くなる。 << Amplification fiber 31 >>
The amplification fiber 31 photoamplifies the signal light. The amplification fiber 31 is, for example, an erbium-added optical fiber (EDF). The signal light branched by the optical coupler 21 and the excitation light output from the excitation light source 24 are input to the amplification fiber 31. The amplification fiber 31 photoamplifies the signal light by the excitation light. As the optical power of the excitation light input to the amplification fiber 31 increases, the degree of optical amplification of the signal light also increases.
≪アイソレータ３２≫
　アイソレータ３２は、一方向に光を伝送する。アイソレータ３２は、増幅用ファイバ３１からの出力された光を通過する。アイソレータ３２は、検出部４０から増幅用ファイバ３１への方向の光を遮断する。 ≪Isolator 32≫
The isolator 32 transmits light in one direction. The isolator 32 passes the light output from the amplification fiber 31. The isolator 32 blocks light in the direction from the detection unit 40 to the amplification fiber 31.
≪検出部４０≫
　検出部４０は、信号光の戻り光を検出する。検出部４０は、比較回路４４を備える。検出部４０は、光カプラ４１、および受光素子４２，４３を備えてもよい。 << Detection unit 40 >>
The detection unit 40 detects the return light of the signal light. The detection unit 40 includes a comparison circuit 44. The detection unit 40 may include an optical coupler 41 and light receiving elements 42 and 43.
≪光カプラ４１≫
　光カプラ４１は、光を分岐する。光カプラ４１は、光増幅部３０の出力光の戻り光を分岐する。つまり、光カプラ４１は、出力端５２の方向からの信号光を分岐する。光カプラ４１は、アイソレータ３２の方向からの信号光を出力端５２に出力する。光カプラ４１は、アイソレータ３２の方向からの信号光を分岐してもよい。 ≪Optical coupler 41≫
The optical coupler 41 branches the light. The optical coupler 41 branches the return light of the output light of the optical amplification unit 30. That is, the optical coupler 41 branches the signal light from the direction of the output end 52. The optical coupler 41 outputs signal light from the direction of the isolator 32 to the output terminal 52. The optical coupler 41 may branch the signal light from the direction of the isolator 32.
≪受光素子４２，４３≫
　受光素子４２，４３は、光を検知する。受光素子４２，４３は、光の検知状況を出力する。受光素子４２は、出力端５２の方向からの戻り光を検知する。受光素子４３は、アイソレータ３２の方向からの信号光を検知する。 << Light receiving elements 42, 43 >>
The light receiving elements 42 and 43 detect light. The light receiving elements 42 and 43 output the light detection status. The light receiving element 42 detects the return light from the direction of the output end 52. The light receiving element 43 detects the signal light from the direction of the isolator 32.
≪比較回路４４≫
　比較回路４４は、戻り光に自光増幅器１の識別信号が含まれているかを検知する。比較回路４４は、受光素子４２が受信した戻り光に含まれる識別信号と、識別情報から想定される識別信号とを比較する。比較回路４４は、駆動部２０に対して、アイセーフ機能を指示する。 ≪Comparison circuit 44≫
The comparison circuit 44 detects whether the return light includes the identification signal of the self-optical amplifier 1. The comparison circuit 44 compares the identification signal included in the return light received by the light receiving element 42 with the identification signal assumed from the identification information. The comparison circuit 44 instructs the drive unit 20 to perform the eye-safe function.
＜光増幅器１の動作＞
　次に、光増幅器１の動作について説明する。 <Operation of optical amplifier 1>
Next, the operation of the optical amplifier 1 will be described.
　信号光は、入力端５１から光増幅器１へ入力される。信号光は、１つの波長の信号光、もしくは複数の波長を含んだ信号光である。信号光は駆動部２０へ出力される。 The signal light is input to the optical amplifier 1 from the input terminal 51. The signal light is a signal light having one wavelength or a signal light including a plurality of wavelengths. The signal light is output to the drive unit 20.
　入力端５１から出力された信号光は、光カプラ２１へ入力される。光カプラ２１は、信号光を分岐して、光増幅部３０と受光素子２２とへ出力する。受光素子２２は、信号光の光レベルを検出し、駆動回路２３へ通知する。駆動回路２３は、受光素子２２から通知される光レベルより、信号光の有無を検知する。受光素子２２への信号光の入力が有る場合、駆動回路２３は励起光源２４に対して励起光の出力を上げるように指示する。受光素子２２への信号光の入力が無い場合、駆動回路２３は励起光源２４に対して励起光の出力を下げるように指示する。 The signal light output from the input end 51 is input to the optical coupler 21. The optical coupler 21 branches the signal light and outputs it to the optical amplification unit 30 and the light receiving element 22. The light receiving element 22 detects the light level of the signal light and notifies the drive circuit 23. The drive circuit 23 detects the presence or absence of signal light from the light level notified from the light receiving element 22. When there is an input of signal light to the light receiving element 22, the drive circuit 23 instructs the excitation light source 24 to increase the output of the excitation light. When there is no signal light input to the light receiving element 22, the drive circuit 23 instructs the excitation light source 24 to reduce the output of the excitation light.
　駆動回路２３は、保持部５０から識別情報を取得する。駆動回路２３は、識別情報から識別信号を生成する。識別信号は、例えば、ある周波数の搬送波にパルス列の情報を乗せた信号である。駆動回路２３は、識別信号を励起光源２４へ出力する。 The drive circuit 23 acquires identification information from the holding unit 50. The drive circuit 23 generates an identification signal from the identification information. The identification signal is, for example, a signal obtained by carrying pulse train information on a carrier wave having a certain frequency. The drive circuit 23 outputs the identification signal to the excitation light source 24.
　受光素子２２への信号光の入力がある場合、駆動回路２３は励起光源２４に対して励起光の出力を上げるように指示する。つまり、光増幅器１に信号光の入力がある場合に、励起光の出力を上げて、信号光を増幅する。駆動回路２３は、信号光の出力レベル調整、およびアイセーフ機能のために、励起光の出力レベルを調整する。この動作については、後述する。 When there is an input of signal light to the light receiving element 22, the drive circuit 23 instructs the excitation light source 24 to increase the output of the excitation light. That is, when the optical amplifier 1 has an input of signal light, the output of the excitation light is increased to amplify the signal light. The drive circuit 23 adjusts the output level of the excitation light for the signal light output level adjustment and the eye-safe function. This operation will be described later.
　励起光源２４は、駆動回路２３より指示された出力レベルで、励起光を出力する。励起光源２４は、駆動回路２３から入力される識別信号で変調した励起光を出力する。例えば、励起光は識別信号によって振幅変調される。識別信号の周波数は信号光の周波数とは異なる。光増幅後の信号光の信号品質の劣化抑制のため、励起光の変調は光増幅器による増幅量の１０％以下の増幅量の変化とする。 The excitation light source 24 outputs excitation light at the output level instructed by the drive circuit 23. The excitation light source 24 outputs excitation light modulated by an identification signal input from the drive circuit 23. For example, the excitation light is amplitude modulated by the identification signal. The frequency of the identification signal is different from the frequency of the signal light. In order to suppress deterioration of the signal quality of the signal light after optical amplification, the modulation of the excitation light is a change in the amplification amount of 10% or less of the amplification amount by the optical amplifier.
　励起光源２４から出力される励起光は、光カプラ２１から出力される信号光と結合され、光増幅部３０へ入力される。識別信号によって変調された励起光と信号光とは、増幅用ファイバ３１へ入力される。増幅用ファイバ３１は、励起光の光レベルに応じて、信号光を光増幅する。増幅用ファイバ３１は、識別信号で変調された信号光を出力する。例えば、信号光は識別信号によって振幅変調される。励起光は、増幅用ファイバ３１を通過時に、信号光の光増幅に用いられ、ほとんど消失する。 The excitation light output from the excitation light source 24 is combined with the signal light output from the optical coupler 21 and input to the optical amplification unit 30. The excitation light and the signal light modulated by the identification signal are input to the amplification fiber 31. The amplification fiber 31 photoamplifies the signal light according to the light level of the excitation light. The amplification fiber 31 outputs signal light modulated by the identification signal. For example, the signal light is amplitude modulated by the identification signal. When the excitation light passes through the amplification fiber 31, it is used for optical amplification of the signal light and almost disappears.
　増幅用ファイバ３１は、光をアイソレータ３２へ出力する。アイソレータ３２は、増幅用ファイバ３１の方向からの光を通過させる。アイソレータ３２は、検出部４０の方向からの光を遮断する。アイソレータ３２は、増幅用ファイバ３１で光増幅した光を通過させる。アイソレータ３２は、増幅用ファイバ３１へ入力する光を遮断する。アイソレータ３２は、検出部４０から増幅用ファイバ３１方向への光を遮断する。 The amplification fiber 31 outputs light to the isolator 32. The isolator 32 allows light from the direction of the amplification fiber 31 to pass through. The isolator 32 blocks light from the direction of the detection unit 40. The isolator 32 passes the light photo-amplified by the amplification fiber 31. The isolator 32 blocks the light input to the amplification fiber 31. The isolator 32 blocks light from the detection unit 40 in the direction of the amplification fiber 31.
　アイソレータ３２は、検出部４０へ光を出力する。検出部４０は、光を光カプラ４１へ出力する。光カプラ４１は、光を分岐する。光カプラ４１は、光増幅部３０からの光を、受光素子４３と出力端５２とに出力する。 The isolator 32 outputs light to the detection unit 40. The detection unit 40 outputs light to the optical coupler 41. The optical coupler 41 branches the light. The optical coupler 41 outputs the light from the optical amplification unit 30 to the light receiving element 43 and the output terminal 52.
　出力端５２は、光カプラ４１からの光を出力する。光増幅器１は、出力端５２から信号光を出力光として出力する。受光素子４３は、光増幅部３０からの光を検知する。受光素子４３は、光増幅部３０から出力される光を検知する。受光素子４３は光を検知したら、検知状況を出力する。受光素子４３は、出力光の検知状況を出力する。 The output end 52 outputs the light from the optical coupler 41. The optical amplifier 1 outputs signal light as output light from the output terminal 52. The light receiving element 43 detects the light from the optical amplifier unit 30. The light receiving element 43 detects the light output from the optical amplifier unit 30. When the light receiving element 43 detects light, it outputs the detection status. The light receiving element 43 outputs the detection status of the output light.
　出力端５２に光ファイバが装着されている場合、出力光は出力端５２から光ファイバに出力される。出力端５２に光ファイバが装着されていない場合、出力端５２でフレネル反射が発生し、出力光の反射光が光カプラ４１方向へ向かう。また、光増幅器１の外部から出力端５２へ入力される光は、光カプラ４１へ送られる。 When an optical fiber is attached to the output end 52, the output light is output from the output end 52 to the optical fiber. When the optical fiber is not attached to the output end 52, Fresnel reflection occurs at the output end 52, and the reflected light of the output light goes in the direction of the optical coupler 41. Further, the light input from the outside of the optical amplifier 1 to the output terminal 52 is sent to the optical coupler 41.
　出力端５２から出力される出力光と伝搬方向が逆の光を「戻り光」とする。そのため、戻り光は、出力光の反射光と、外部から出力端５２へ入力される光とを含む。以降、出力端５２から光増幅器１内へ向かう光を戻り光とする。 "Return light" is light whose propagation direction is opposite to that of the output light output from the output end 52. Therefore, the return light includes the reflected light of the output light and the light input from the outside to the output terminal 52. Hereinafter, the light directed from the output terminal 52 into the optical amplifier 1 is referred to as return light.
　光カプラ４１は、出力端５２からの戻り光を分岐し、アイソレータ３２と受光素子４２とへ出力する。アイソレータ３２には、戻り光を遮断する。受光素子４２は、戻り光を検知する。受光素子４２は光を検知したら、比較回路４４に検知状況を通知する。 The optical coupler 41 branches the return light from the output terminal 52 and outputs it to the isolator 32 and the light receiving element 42. The isolator 32 blocks the return light. The light receiving element 42 detects the return light. When the light receiving element 42 detects the light, it notifies the comparison circuit 44 of the detection status.
　比較回路４４は、保持部５０から識別情報を取得する。比較回路４４は、識別情報から自光増幅器１の識別信号を認識する。比較回路４４は、受光素子４２が検出した戻り光に、自光増幅器１の識別信号が含まれているか確認する。戻り光に自光増幅器１の識別信号が含まれている場合、比較回路４４は、出力端５２に光ファイバが装着されていないと判断する。 The comparison circuit 44 acquires identification information from the holding unit 50. The comparison circuit 44 recognizes the identification signal of the self-optical amplifier 1 from the identification information. The comparison circuit 44 confirms whether the return light detected by the light receiving element 42 includes the identification signal of the self-optical amplifier 1. When the return light includes the identification signal of the self-optical amplifier 1, the comparison circuit 44 determines that the optical fiber is not mounted on the output terminal 52.
　出力端５２に光ファイバが装着されていないと判断したら、比較回路４４は、アイセーフ機能を起動する。アイセーフ機能の起動は、以下の手順で行われる。比較回路４４は、駆動部２０に対して、励起光の出力レベルを下げるように制御する。駆動部２０内の駆動回路２３は、励起光の出力レベルを下げるように励起光源２４に指示する。励起光の出力レベルが下がると、光増幅部３０で光増幅が行われず、出力光の光レベルは低下する。このようにして、アイセーフ機能が実施される。 If it is determined that the optical fiber is not attached to the output terminal 52, the comparison circuit 44 activates the eye safe function. The iSafe function is activated by the following procedure. The comparison circuit 44 controls the drive unit 20 to lower the output level of the excitation light. The drive circuit 23 in the drive unit 20 instructs the excitation light source 24 to lower the output level of the excitation light. When the output level of the excitation light is lowered, the optical amplification unit 30 does not perform optical amplification, and the light level of the output light is lowered. In this way, the eye-safe function is implemented.
　実際に、出力端５２に光ファイバが装着されていない場合、光増幅器１内での動作は以下のようになる。出力端５２で反射光が発生する。光カプラ４１は反射光を受光素子４２へ出力する。比較回路４４は、受光素子４２で検出した反射光の中に、自光増幅器１の識別信号が含まれている場合、アイセーフ機能を起動する。 Actually, when the optical fiber is not attached to the output terminal 52, the operation in the optical amplifier 1 is as follows. Reflected light is generated at the output end 52. The optical coupler 41 outputs the reflected light to the light receiving element 42. The comparison circuit 44 activates the eye-safe function when the identification signal of the self-optical amplifier 1 is included in the reflected light detected by the light receiving element 42.
　また、スイッチ４などの外部装置から出力端５２へ光が入力された場合、光増幅器１内での動作は以下のようになる。出力端５２で戻り光が発生する。光カプラ４１は戻り光を受光素子４２へ出力する。比較回路４４は、受光素子４２で検出した戻り光の中に、自光増幅器１の識別信号を検出できない。そのため、比較回路４４はアイセーフ機能を起動しない。 Further, when light is input to the output terminal 52 from an external device such as a switch 4, the operation in the optical amplifier 1 is as follows. Return light is generated at the output terminal 52. The optical coupler 41 outputs the return light to the light receiving element 42. The comparison circuit 44 cannot detect the identification signal of the self-optical amplifier 1 in the return light detected by the light receiving element 42. Therefore, the comparison circuit 44 does not activate the eye-safe function.
　以上のように、戻り光内の自光増幅器１の識別信号の有無により、光ファイバ抜けを判断するようにしたため、光ファイバ抜けの確度を向上することができる。そして、不要なアイセーフ機能の起動を避けることができる。 As described above, since the optical fiber omission is determined based on the presence or absence of the identification signal of the self-optical amplifier 1 in the return light, the accuracy of the optical fiber omission can be improved. And it is possible to avoid unnecessary activation of the eye safe function.
　次に、光ファイバ抜け以外の原因で反射光が発生する場合についての光増幅器１の動作を説明する。 Next, the operation of the optical amplifier 1 in the case where the reflected light is generated due to a cause other than the loss of the optical fiber will be described.
　光増幅器１を含むシステム内で反射光が発生する場合、出力端５２における光ファイバ抜けの場合と比べて、その反射光の光レベルは十分に小さい。そのため、戻り光の自光増幅器１の識別信号の光レベルが、出力光の識別信号の光レベルに比べて十分に小さい場合、光ファイバ抜けが発生していないと判断できる。 When reflected light is generated in the system including the optical amplifier 1, the light level of the reflected light is sufficiently smaller than that in the case where the optical fiber is pulled out at the output terminal 52. Therefore, when the optical level of the identification signal of the self-optical amplifier 1 of the return light is sufficiently smaller than the optical level of the identification signal of the output light, it can be determined that the optical fiber is not dropped.
　光カプラ４１は、光増幅部３０からの光を分岐して、出力端５２および受光素子４３に出力する。そのため、受光素子４３は出力光に相当する光を検知する。一方、受光素子４２は、戻り光を検知する。そのため、比較回路４４は、受光素子４２，４３の検知状況から、出力光の反射率を認識できる。 The optical coupler 41 branches the light from the optical amplification unit 30 and outputs the light to the output terminal 52 and the light receiving element 43. Therefore, the light receiving element 43 detects light corresponding to the output light. On the other hand, the light receiving element 42 detects the return light. Therefore, the comparison circuit 44 can recognize the reflectance of the output light from the detection status of the light receiving elements 42 and 43.
　比較回路４４は、受光素子４３で検出した光の中に、自光増幅器１の識別信号を検出できる。識別信号の光レベルは、出力光の出力レベルに相当する。また、比較回路４４は、受光素子４２で検出する光の中に自光増幅器１の識別信号を検出したら、その識別信号の光レベルによって、反射光の光レベルを認識できる。そのため、比較回路４４は、受光素子４３および受光素子４２で検出される識別信号の光の強さを比較することによって、識別信号の反射率を認識できる。 The comparison circuit 44 can detect the identification signal of the self-optical amplifier 1 in the light detected by the light receiving element 43. The light level of the identification signal corresponds to the output level of the output light. Further, when the comparison circuit 44 detects the identification signal of the self-optical amplifier 1 in the light detected by the light receiving element 42, the comparison circuit 44 can recognize the light level of the reflected light by the light level of the identification signal. Therefore, the comparison circuit 44 can recognize the reflectance of the identification signal by comparing the light intensity of the identification signal detected by the light receiving element 43 and the light receiving element 42.
　識別信号の反射率が低い場合、比較回路４４は光ファイバが装着されていると判断して、アイセーフ機能を実施しない。識別信号の反射率が高い場合、比較回路４４は光ファイバが装着されていないと判断して、アイセーフ機能を実施する。出力端５２に光ファイバが装着されている場合でも、反射光がわずかに発生することを考慮した対応例である。 If the reflectance of the identification signal is low, the comparison circuit 44 determines that the optical fiber is attached and does not perform the eye-safe function. When the reflectance of the identification signal is high, the comparison circuit 44 determines that the optical fiber is not mounted and performs the eye-safe function. This is a corresponding example in consideration of the fact that a slight amount of reflected light is generated even when an optical fiber is attached to the output end 52.
　つまり、出力光内の識別信号の光レベルに対する戻り光内の自光増幅器１の識別信号の光レベルの割合が所定の割合に満たない場合、検出部４０の比較回路４４は励起光の出力レベルを下げない。ここで所定の割合は、光ファイバ抜けが発生した際の識別信号の光レベル割合より小さい割合である。 That is, when the ratio of the light level of the identification signal of the self-optical amplifier 1 in the return light to the light level of the identification signal in the output light is less than a predetermined ratio, the comparison circuit 44 of the detection unit 40 uses the output level of the excitation light. Do not lower. Here, the predetermined ratio is smaller than the optical level ratio of the identification signal when the optical fiber is disconnected.
　受光素子２２で検出する光のレベルは光増幅前の信号光の光レベルに相当し、受光素子４３で検出する信号光の光レベルは光増幅後の信号光の光レベルに相当する。そのため、駆動回路２３は、受光素子２２で検出する光のレベルと、受光素子４３で検出する光のレベルとを比較することで、光増幅部３０における光増幅の度合いを認識できる。光増幅の度合いが足りない場合には、駆動回路２３は励起光源２４に対して励起光の出力レベルを上げるように指示する。このようにして、光増幅器１は励起光の出力レベルを調整することで、信号光の出力レベルの調整を行うことができる。 The level of light detected by the light receiving element 22 corresponds to the light level of the signal light before light amplification, and the light level of the signal light detected by the light receiving element 43 corresponds to the light level of the signal light after light amplification. Therefore, the drive circuit 23 can recognize the degree of light amplification in the optical amplification unit 30 by comparing the level of light detected by the light receiving element 22 with the level of light detected by the light receiving element 43. When the degree of optical amplification is insufficient, the drive circuit 23 instructs the excitation light source 24 to increase the output level of the excitation light. In this way, the optical amplifier 1 can adjust the output level of the signal light by adjusting the output level of the excitation light.
　図１の光増幅器１は、識別信号で変調した励起光によって信号光を光増幅している。そして光増幅部３０は、識別信号で変調された信号光を出力している。しかしながら、光増幅器１は、識別信号と信号光とを多重して出力してもよい。励起光源２４は、励起光と識別信号とを出力することで、光増幅部３０は、識別信号と信号光とを出力する。また、光増幅器１は、光増幅後の信号光と識別信号を多重してもよい。つまり、光増幅部３０より出力される信号光に対して、識別信号を多重してもよい。この場合、駆動回路２３以外の構成要素で識別信号を生成してもよい。 The optical amplifier 1 of FIG. 1 photoamplifies the signal light by the excitation light modulated by the identification signal. Then, the optical amplification unit 30 outputs the signal light modulated by the identification signal. However, the optical amplifier 1 may multiplex and output the identification signal and the signal light. The excitation light source 24 outputs the excitation light and the identification signal, and the optical amplification unit 30 outputs the identification signal and the signal light. Further, the optical amplifier 1 may multiplex the signal light after optical amplification and the identification signal. That is, the identification signal may be multiplexed with respect to the signal light output from the optical amplification unit 30. In this case, the identification signal may be generated by a component other than the drive circuit 23.
　図３は、光伝送システム１０の動作の一例を示す説明図である。図３において、各構成要素は図１と同じである。 FIG. 3 is an explanatory diagram showing an example of the operation of the optical transmission system 10. In FIG. 3, each component is the same as in FIG.
　図１では、一番上の入力ポート５から入力した特定の周波数の光をミラー８で反射し、一番下の出力ポート６から出力している。図１と同様に、図３では一番上の入力ポート５から入力した特定の周波数の光（実線の矢印）をミラー８で反射し、一番下の出力ポート６から出力している。このとき、スイッチ４内で所望ポート以外に光が漏れこむことがある。図３では、意図せずに、上から２番目の入力ポート５から入力した特定の周波数の光（点線の矢印）をミラー８で反射し、一番下の入力ポート５へ出力している。 In FIG. 1, light of a specific frequency input from the top input port 5 is reflected by the mirror 8 and output from the bottom output port 6. Similar to FIG. 1, in FIG. 3, light of a specific frequency (solid arrow) input from the top input port 5 is reflected by the mirror 8 and output from the bottom output port 6. At this time, light may leak into the switch 4 to a port other than the desired port. In FIG. 3, unintentionally, light of a specific frequency (dotted arrow) input from the second input port 5 from the top is reflected by the mirror 8 and output to the bottom input port 5.
　一番下の入力ポート５に接続している光増幅器１は、上から２番目の入力ポート５から入力した特定の周波数の光を出力端５２から受信する。光増幅器１内では、出力端５２から入力する光を、受光素子４２で検知する。比較回路４４は、受光素子４２で検知した光に、自光増幅器１が出力した識別信号が含まれていないため、光ファイバ外れではないと判断し、アイセーフ機能を起動しない。なお、従来の光増幅器を用いた場合には、入力ポート５から受信した光の光レベルによりアイセーフ機能が起動してしまう。 The optical amplifier 1 connected to the bottom input port 5 receives light of a specific frequency input from the second input port 5 from the top from the output terminal 52. In the optical amplifier 1, the light input from the output terminal 52 is detected by the light receiving element 42. Since the light detected by the light receiving element 42 does not include the identification signal output by the self-optical amplifier 1, the comparison circuit 44 determines that the optical fiber is not disconnected and does not activate the eye safe function. When a conventional optical amplifier is used, the eye safe function is activated depending on the light level of the light received from the input port 5.
　図４は、光伝送システム１０の動作の他の例を示す説明図である。図４において、各構成要素は図１および図３と同じである。 FIG. 4 is an explanatory diagram showing another example of the operation of the optical transmission system 10. In FIG. 4, each component is the same as in FIGS. 1 and 3.
　光増幅器１ａ～１ｍが出力する識別信号について説明する。識別信号は、例えば、ある周波数の搬送波に４ビットのパルス列の情報を乗せた信号である。光増幅器１ａ～１ｍは、それぞれ異なるパルス列を出力する。 The identification signal output by the optical amplifiers 1a to 1m will be described. The identification signal is, for example, a signal obtained by carrying information of a 4-bit pulse train on a carrier wave having a certain frequency. The optical amplifiers 1a to 1m output different pulse trains.
　図４において、光増幅器１ｂは４ビットの１０１０のパルス列を含む識別信号によって変調された信号光を出力する。光増幅器１ｂからの信号光は、スイッチ４の入力ポート５ｂに入力される。光増幅器１ｍは４ビットの１１１０のパルス列を含む識別信号によって変調された信号光を出力する。光増幅器１ｍからの信号光は、スイッチ４の入力ポート５ｍに入力される。 In FIG. 4, the optical amplifier 1b outputs signal light modulated by an identification signal including a 4-bit 1010 pulse train. The signal light from the optical amplifier 1b is input to the input port 5b of the switch 4. The optical amplifier 1 m outputs signal light modulated by an identification signal including a 4-bit 1110 pulse train. The signal light from the optical amplifier 1 m is input to the input port 5 m of the switch 4.
　通常、入力ポート５から信号光は出力されない。スイッチ４内で所望ポート以外に光が漏れこむ現象が発生した場合、例えば、入力ポート５ｂから入力した信号光の一部が入力ポート５ｍから出力される。そのため、パルス列１０１０を含む識別信号によって変調された信号光は、光増幅器１ｍの出力端５２へ入力される。 Normally, no signal light is output from the input port 5. When a phenomenon occurs in the switch 4 in which light leaks to a port other than the desired port, for example, a part of the signal light input from the input port 5b is output from the input port 5m. Therefore, the signal light modulated by the identification signal including the pulse train 1010 is input to the output terminal 52 of the optical amplifier 1 m.
　光増幅器１内では、出力端５２から入力したパルス列１０１０を含む信号光を、受光素子４２で検知する。比較回路４４は、受光素子４２で検知した光に、光増幅器１ｍが出力した識別信号（パルス列１１１０）が含まれていないため、光ファイバ外れではないと判断し、アイセーフ機能を起動しない。 In the optical amplifier 1, the light receiving element 42 detects the signal light including the pulse train 1010 input from the output terminal 52. Since the light detected by the light receiving element 42 does not include the identification signal (pulse train 1110) output by the optical amplifier 1m, the comparison circuit 44 determines that the optical fiber is not disconnected and does not activate the eye safe function.
　光増幅器１ｍで光ファイバ外れが発生した場合には、光増幅器１ｍが出力しようとした信号光は出力端５２で反射し、受光素子４２で検知される。比較回路４４は、受光素子４２で検知した光にパルス列１１１０が含まれていることを検出し、光ファイバ外れと判断し、アイセーフ機能を起動する。このように、スイッチ４内で所望ポート以外に光が漏れこむ現象が発生した場合でも、光ファイバ外れか否かの判別の精度を高くできる。 When the optical fiber is disconnected from the optical amplifier 1 m, the signal light that the optical amplifier 1 m tries to output is reflected by the output end 52 and detected by the light receiving element 42. The comparison circuit 44 detects that the light detected by the light receiving element 42 includes the pulse train 1110, determines that the optical fiber is disconnected, and activates the eye safe function. In this way, even when a phenomenon in which light leaks to a port other than the desired port occurs in the switch 4, the accuracy of determining whether or not the optical fiber is disconnected can be improved.
　スイッチ４内で所望ポート以外に光が漏れこむ現象が発生する場合、入力ポート５にアイソレータを接続することで、入力ポート５からの信号光の出力を遮断することが可能である。つまり、従来の光増幅器を使用してシステムを構築する場合には、入力ポート数分のアイソレータを用意する必要がある。一方、実施の形態１に係る光増幅器１を用いることで、スイッチ４内で所望ポート以外に光が漏れこむ現象が発生するシステムにおいてアイソレータが不要となる。 When a phenomenon occurs in the switch 4 in which light leaks to a port other than the desired port, it is possible to block the output of the signal light from the input port 5 by connecting an isolator to the input port 5. That is, when constructing a system using a conventional optical amplifier, it is necessary to prepare isolators for the number of input ports. On the other hand, by using the optical amplifier 1 according to the first embodiment, the isolator becomes unnecessary in the system in which the phenomenon of light leaking into the switch 4 other than the desired port occurs.
＜処理フローチャート＞
　図５は、光増幅器１の処理フローの一例を示すフローチャートである。図４に示すように、光伝送システム１０において光増幅器１ｂの出力光がスイッチ４を介して光増幅器１ｍへ入力することを想定した処理フロー例である。図４において、各光増幅器１はそれぞれ異なる識別信号を出力することを想定しているが、このフローチャートにおいては他の光増幅器１が同じ識別信号を出力する場合にも対応する。 <Processing flowchart>
FIG. 5 is a flowchart showing an example of the processing flow of the optical amplifier 1. As shown in FIG. 4, this is an example of a processing flow assuming that the output light of the optical amplifier 1b is input to the optical amplifier 1m via the switch 4 in the optical transmission system 10. In FIG. 4, it is assumed that each optical amplifier 1 outputs a different identification signal, but in this flowchart, it corresponds to the case where another optical amplifier 1 outputs the same identification signal.
　図５に基づいて、光増幅器１の動作を説明する。ステップＳ１において、光増幅器１の入力端５１に信号光を入力する。光増幅器１に信号光を入力することで、光増幅器１の光増幅処理を開始する。そしてステップＳ２へ進む。 The operation of the optical amplifier 1 will be described with reference to FIG. In step S1, signal light is input to the input terminal 51 of the optical amplifier 1. By inputting signal light to the optical amplifier 1, the optical amplification process of the optical amplifier 1 is started. Then, the process proceeds to step S2.
　ステップＳ２において、受光素子４３で戻り光を検出し、そして比較回路４４で戻り光に自光増幅器１の識別信号が含まれているかを確認する。戻り光は、出力光が出力端５２で反射した光と、光増幅器１の外部から出力端５２を介して入力する光とを含む。ここで、識別信号は、特定の周波数の搬送波に任意のパルス列の情報を乗せた信号とする。そのため、例えば、保持部５０で保持している識別情報の周波数情報が一致する識別信号である。 In step S2, the light receiving element 43 detects the return light, and the comparison circuit 44 confirms whether the return light includes the identification signal of the self-optical amplifier 1. The return light includes light reflected by the output light at the output terminal 52 and light input from the outside of the optical amplifier 1 via the output terminal 52. Here, the identification signal is a signal obtained by carrying information of an arbitrary pulse train on a carrier wave having a specific frequency. Therefore, for example, it is an identification signal in which the frequency information of the identification information held by the holding unit 50 matches.
　戻り光が検出されない場合、ステップＳ３へ進む。戻り光が検出され、かつ戻り光に識別信号が含まれていない場合、ステップＳ３へ進む。戻り光が検出され、かつ戻り光に識別信号が含まれている場合、ステップＳ４へ進む。 If no return light is detected, proceed to step S3. If the return light is detected and the return light does not contain an identification signal, the process proceeds to step S3. If the return light is detected and the return light contains an identification signal, the process proceeds to step S4.
　ステップＳ３において、駆動回路２３は保持部５０の識別情報を用いて、識別信号を生成し、励起光源２４に出力する。そしてステップＳ５へ進む。 In step S3, the drive circuit 23 uses the identification information of the holding unit 50 to generate an identification signal and outputs it to the excitation light source 24. Then, the process proceeds to step S5.
　ステップＳ４において、システム内で動作中の他の光増幅器１からの識別信号を受信している可能性があるため、比較回路４４で戻り光に含まれる識別信号を調査する。保持部５０の識別情報を用いて生成する識別信号と戻り光の識別信号とが異なる場合、駆動回路２３は保持部５０の識別情報を用いて、識別信号を生成し、励起光源２４に出力する。 In step S4, since there is a possibility that the identification signal from another optical amplifier 1 operating in the system is received, the identification signal included in the return light is investigated by the comparison circuit 44. When the identification signal generated by using the identification information of the holding unit 50 and the identification signal of the return light are different, the drive circuit 23 generates an identification signal by using the identification information of the holding unit 50 and outputs it to the excitation light source 24. ..
　保持部５０の識別情報を用いて生成する識別信号と戻り光の識別信号とが同じ場合、駆動回路２３は保持部５０の識別情報を変更し、変更した識別情報から識別信号を生成し、励起光源２４に出力する。識別信号が同じとは、例えば、４ビットのパルス列（例えば１１１０）が同じことである。この場合はパルス列を異なるものに変更する。生成した識別信号に関する識別情報を保持部５０に保持する。そしてステップＳ５へ進む。 When the identification signal generated by using the identification information of the holding unit 50 and the identification signal of the return light are the same, the drive circuit 23 changes the identification information of the holding unit 50, generates an identification signal from the changed identification information, and excites. Output to the light source 24. The same identification signal means, for example, the same 4-bit pulse train (for example, 1110). In this case, change the pulse train to a different one. The identification information regarding the generated identification signal is held in the holding unit 50. Then, the process proceeds to step S5.
　ステップＳ５において、光増幅器１は光増幅を開始する。駆動回路２３は励起光源２４に対して励起光の出力を上げるように指示する。増幅用ファイバ３１内で、励起光の光レベルに応じて、信号光は光増幅される。光増幅された信号光は、識別信号によって変調されて、光増幅器１より出力光として出力される。そしてステップＳ６へ進む。 In step S5, the optical amplifier 1 starts optical amplification. The drive circuit 23 instructs the excitation light source 24 to increase the output of the excitation light. In the amplification fiber 31, the signal light is photo-amplified according to the light level of the excitation light. The light-amplified signal light is modulated by the identification signal and output from the optical amplifier 1 as output light. Then, the process proceeds to step S6.
　ステップＳ６において、駆動回路２３で生成した識別信号と同じ識別信号が、戻り光に含まれているか確認する。つまり、比較回路４４は受光素子４３で検出した光に、保持部５０の識別情報を用いて生成される識別信号が含まれているかを確認する。 In step S6, it is confirmed whether the return light contains the same identification signal as the identification signal generated by the drive circuit 23. That is, the comparison circuit 44 confirms whether the light detected by the light receiving element 43 includes an identification signal generated by using the identification information of the holding unit 50.
　戻り光に同一の識別信号が含まれていない場合、ステップＳ６に戻る。つまり、戻り光に同一の識別信号が含まれているかを確認し続ける。戻り光に同一の識別信号が含まれている場合、ステップＳ７へ進む。 If the return light does not contain the same identification signal, the process returns to step S6. That is, it keeps checking whether the return light contains the same identification signal. If the return light contains the same identification signal, the process proceeds to step S7.
　ステップＳ７において、光増幅器１は光増幅を中断する。比較回路４４は反射光を検知したため、光ファイバが装着されていない可能性があると判断したためである。駆動回路２３は、励起光源２４に対して励起光の出力を下げるように指示する。増幅用ファイバ３１内で、励起光の光レベルが下がるため、信号光は光増幅されない。このようにアイセーフ機能が起動する。ステップＳ８へ進む。 In step S7, the optical amplifier 1 interrupts the optical amplification. This is because the comparison circuit 44 has detected the reflected light and has determined that the optical fiber may not be attached. The drive circuit 23 instructs the excitation light source 24 to reduce the output of the excitation light. Since the light level of the excitation light is lowered in the amplification fiber 31, the signal light is not photoamplified. In this way, the eye safe function is activated. Proceed to step S8.
　ステップＳ６でｙｅｓと判断したときは、出力端５２に光ファイバが装着されていない場合と他の光増幅器１が同じ識別信号を出力している場合とが考えられる。そのため、他の光増幅器１が同じ識別信号を出力しているかを確認する。確認する方法は、出力する識別信号を変更することで、戻り光の識別信号が変化するかを調査する。 When it is determined to be yes in step S6, it is considered that the optical fiber is not mounted on the output terminal 52 and the other optical amplifier 1 outputs the same identification signal. Therefore, it is confirmed whether the other optical amplifier 1 outputs the same identification signal. The confirmation method is to investigate whether the identification signal of the return light changes by changing the identification signal to be output.
　ステップＳ８において、光増幅器１は出力する識別信号を変更する。駆動回路２３は保持部５０の識別情報を変更し、変更した識別情報から識別信号を生成し、励起光源２４に出力する。ステップＳ９へ進む。 In step S8, the optical amplifier 1 changes the identification signal to be output. The drive circuit 23 changes the identification information of the holding unit 50, generates an identification signal from the changed identification information, and outputs the identification signal to the excitation light source 24. Proceed to step S9.
　ステップＳ９において、駆動回路２３で生成した識別信号と同じ識別信号が、戻り光に含まれているか確認する。つまり、比較回路４４は受光素子４３で検出した光に、保持部５０の識別情報を用いて生成される識別信号が含まれているかを確認する。 In step S9, it is confirmed whether the return light contains the same identification signal as the identification signal generated by the drive circuit 23. That is, the comparison circuit 44 confirms whether the light detected by the light receiving element 43 includes an identification signal generated by using the identification information of the holding unit 50.
　戻り光に同一の識別信号が含まれていない場合、ステップＳ５へ進む。つまり、光ファイバ抜けによる反射光が発生していないと判断し、光増幅を再開する。戻り光に同一の識別信号が含まれている場合、ステップＳ１０へ進む。 If the return light does not contain the same identification signal, the process proceeds to step S5. That is, it is determined that the reflected light due to the loss of the optical fiber is not generated, and the optical amplification is restarted. If the return light contains the same identification signal, the process proceeds to step S10.
　ステップＳ１０において、同一の識別信号が含まれる戻り光が消滅するのを待つ。つまり、駆動回路２３で生成した識別信号と同じ識別信号が、受光素子４３で検出した戻り光に含まれなくなるまで待機する。これは、光ファイバが装着されずに反射光が検知されていると判断して、反射光がなくなるまで光増幅を中断する。そして、同一の識別信号が含まれていた戻り光が検出されなくなったら、ステップＳ５へ進む。つまり、光ファイバ抜けによる反射光が発生していないと判断し、光増幅を再開する。 In step S10, wait for the return light containing the same identification signal to disappear. That is, it waits until the same identification signal as the identification signal generated by the drive circuit 23 is not included in the return light detected by the light receiving element 43. This determines that the reflected light is detected without the optical fiber being attached, and interrupts the optical amplification until the reflected light disappears. Then, when the return light containing the same identification signal is no longer detected, the process proceeds to step S5. That is, it is determined that the reflected light due to the loss of the optical fiber is not generated, and the optical amplification is restarted.
≪変形例１≫
　各光増幅器１が出力する識別信号を一元管理するシステム例を示す。図６は、実施の形態１の変形例１に係る光伝送システム１１を示す構成図である。 << Modification 1 >>
An example of a system for centrally managing the identification signal output by each optical amplifier 1 is shown. FIG. 6 is a configuration diagram showing an optical transmission system 11 according to a modification 1 of the first embodiment.
　光伝送システム１１は、光伝送システム１０に対して、管理装置６０を追加したものである。他の構成要素は、図１と同じであるので、説明を省略する。 The optical transmission system 11 is an optical transmission system 10 to which a management device 60 is added. Since the other components are the same as those in FIG. 1, the description thereof will be omitted.
＜光伝送システム１１の構成＞
　光伝送システム１１は、スイッチ４および管理装置６０を備える。光伝送システム１１は、複数のトランスポンダ２、複数の光合波器３、および複数の光増幅器１を備えることができる。 <Configuration of optical transmission system 11>
The optical transmission system 11 includes a switch 4 and a management device 60. The optical transmission system 11 can include a plurality of transponders 2, a plurality of optical combiners 3, and a plurality of optical amplifiers 1.
≪管理装置６０≫
　管理装置６０は、光増幅器１に識別情報を通知する。管理装置６０は、例えば、テーブル６１を備える。管理装置６０は、各光増幅器１に通知する識別情報をテーブル６１に保持する。 << Management device 60 >>
The management device 60 notifies the optical amplifier 1 of the identification information. The management device 60 includes, for example, a table 61. The management device 60 holds the identification information to be notified to each optical amplifier 1 in the table 61.
＜光伝送システム１１の動作＞
　次に、光伝送システム１１の動作について説明する。管理装置６０に関する動作以外は、光伝送システム１０と同じなので説明を省略する。 <Operation of optical transmission system 11>
Next, the operation of the optical transmission system 11 will be described. Since it is the same as the optical transmission system 10 except for the operation related to the management device 60, the description thereof will be omitted.
　管理装置６０は、光伝送システム１１に含まれる光増幅器１を認識している。管理装置６０は、光増幅器１の台数分の識別情報をテーブル６１に保持する。テーブル６１内の識別情報は、それぞれ異なる情報である。管理装置６０は、各光増幅器１にそれぞれ異なる識別情報を通知する。管理装置６０から各光増幅器１に向かう点線の矢印は、識別情報の通知を示している。 The management device 60 recognizes the optical amplifier 1 included in the optical transmission system 11. The management device 60 holds identification information for the number of optical amplifiers 1 in the table 61. The identification information in the table 61 is different information. The management device 60 notifies each optical amplifier 1 of different identification information. The dotted arrow from the management device 60 to each optical amplifier 1 indicates notification of identification information.
　光増幅器１は、管理装置６０より識別情報を通知されると、保持部５０に識別情報を格納する。光増幅器１は、動作時、保持部５０の識別情報より識別信号を生成して出力する。各光増幅器１は、それぞれ異なる識別情報を保持部５０に保持している。各光増幅器１は、それぞれ異なる識別信号を生成して出力する。 When the optical amplifier 1 is notified of the identification information by the management device 60, the optical amplifier 1 stores the identification information in the holding unit 50. During operation, the optical amplifier 1 generates and outputs an identification signal from the identification information of the holding unit 50. Each optical amplifier 1 holds different identification information in the holding unit 50. Each optical amplifier 1 generates and outputs different identification signals.
　このように、管理装置６０を用いて、各光増幅器１がそれぞれ異なる識別信号を出力するようにした。これによって、スイッチ４内で所望ポート以外に光が漏れこむ現象が発生した場合でも、光増幅器１は他の光増幅器１の信号光を認識でき、光ファイバ外れと誤認識しなくなる。 In this way, using the management device 60, each optical amplifier 1 outputs a different identification signal. As a result, even if a phenomenon occurs in the switch 4 in which light leaks to a port other than the desired port, the optical amplifier 1 can recognize the signal light of the other optical amplifier 1 and does not erroneously recognize that the optical fiber is disconnected.
　実施の形態１の変形例１に係る光増幅器１の処理フローチャートは、図５のフローチャートから次のステップが変更になる。ステップＳ２，Ｓ４，Ｓ８，Ｓ９が無くなる。ステップＳ１からステップＳ３へ進む。ステップＳ７からステップＳ１０へ進む。 The processing flowchart of the optical amplifier 1 according to the first modification of the first embodiment is changed from the flowchart of FIG. 5 in the next step. Steps S2, S4, S8, S9 are eliminated. The process proceeds from step S1 to step S3. The process proceeds from step S7 to step S10.
　また、以上のように実施の形態について説明したが、これらの実施の形態は一例である。 Although the embodiments have been described above, these embodiments are examples.
　１，１ａ，１ｂ，１ｍ　光増幅器、２　トランスポンダ、３　光合波器、４　スイッチ、５，５ａ，５ｂ，５ｍ　入力ポート、６　出力ポート、７　光学素子、８　ミラー、１０，１１　光伝送システム、２０　駆動部、２１　光カプラ、２２　受光素子、２３　駆動回路、２４　励起光源、３０　光増幅部、３１　増幅用ファイバ、３２　アイソレータ、４０　検出部、４１　光カプラ、４２，４３　受光素子、４４　比較回路、５０　保持部、５１　入力端、５２　出力端、６０　管理装置、６１　テーブル。 1,1a, 1b, 1m optical amplifier, 2 light source, 3 optical combiner, 4 switch, 5,5a, 5b, 5m input port, 6 output port, 7 optical element, 8 mirror, 10,11 optical transmission system, 20 Drive unit, 21 optical coupler, 22 light receiving element, 23 drive circuit, 24 excitation light source, 30 optical amplification unit, 31 amplification fiber, 32 isolator, 40 detection unit, 41 optical coupler, 42, 43 light receiving element, 44 comparison circuit, 50 holding part, 51 input end, 52 output end, 60 management device, 61 table.

Claims (9)

  1. 　信号光を光増幅する光増幅器であって、
    　前記光増幅器を識別する識別信号によって光増幅用の励起光を変調する駆動部と、
    　前記駆動部から出力される前記励起光を用いて前記信号光を光増幅し、出力光として外部に出力する光増幅部と、
    　前記出力光と伝搬方向が逆となる戻り光を検出し、前記戻り光に自光増幅器の前記識別信号が含まれている場合に、前記励起光の出力レベルを下げる制御を行う検出部と
    　を備えた光増幅器。     An optical amplifier that photoamplifies signal light.
    A drive unit that modulates the excitation light for optical amplification with an identification signal that identifies the optical amplifier,
    An optical amplifier unit that photoamplifies the signal light using the excitation light output from the drive unit and outputs the signal light to the outside as output light.
    A detection unit that detects return light whose propagation direction is opposite to that of the output light and controls to lower the output level of the excitation light when the return light includes the identification signal of the self-optical amplifier. Equipped with an optical amplifier.
  2. 　前記識別信号は、信号光の周波数と異なる周波数の搬送波にパルス列の情報を乗せた信号であり、
    　前記パルス列の違いによって自光増幅器の前記識別信号を識別することを特徴とする請求項１に記載の光増幅器。     The identification signal is a signal obtained by carrying pulse train information on a carrier wave having a frequency different from that of the signal light.
    The optical amplifier according to claim 1, wherein the identification signal of the self-optical amplifier is identified by a difference in the pulse train.
  3. 　前記識別信号は、任意の周波数の搬送波にパルス列の情報を乗せた信号であり、
    　前記識別信号の前記搬送波の周波数の違いによって自光増幅器の前記識別信号を識別することを特徴とする請求項１に記載の光増幅器。     The identification signal is a signal obtained by carrying pulse train information on a carrier wave of an arbitrary frequency.
    The optical amplifier according to claim 1, wherein the identification signal of the self-optical amplifier is identified by a difference in the frequency of the carrier wave of the identification signal.
  4. 　前記識別信号は、任意の周波数の搬送波にパルス列の情報を乗せた信号であり、
    前記識別信号の前記搬送波の周波数と前記パルス列との組み合わせの違いによって、自光増幅器の前記識別信号を識別することを特徴とする請求項１に記載の光増幅器。     The identification signal is a signal obtained by carrying pulse train information on a carrier wave of an arbitrary frequency.
    The optical amplifier according to claim 1, wherein the identification signal of the self-optical amplifier is identified by a difference in the combination of the frequency of the carrier wave of the identification signal and the pulse train.
  5. 　前記検出部が前記駆動部で出力した前記識別信号を検出した場合に、前記駆動部は前記識別信号を変更することを特徴とする請求項１～４のいずれか１項に記載の光増幅器。 The optical amplifier according to any one of claims 1 to 4, wherein when the detection unit detects the identification signal output by the drive unit, the drive unit changes the identification signal.
  6. 　前記検出部は前記出力光と前記戻り光との前記識別信号の光レベルを検出し、前記出力光の前記識別信号の光レベルに対する前記戻り光の自光増幅器の前記識別信号の光レベルの割合が所定の割合を満たさない場合に、前記励起光の出力レベルを下げないことを特徴とする請求項１～５のいずれか１項に記載の光増幅器。 The detection unit detects the light level of the identification signal of the output light and the return light, and the ratio of the light level of the identification signal of the self-lighting amplifier of the return light to the light level of the identification signal of the output light. The optical amplifier according to any one of claims 1 to 5, wherein the output level of the excitation light is not lowered when the temperature does not satisfy a predetermined ratio.
  7. 　複数の請求項１～６のいずれか１項に記載の光増幅器と、
    　複数の前記光増幅器からの出力光を選択して出力するスイッチと
    を備え、
    　複数の前記光増幅器の識別信号が互いに異なることを特徴とする光伝送システム。     The optical amplifier according to any one of claims 1 to 6,
    It is equipped with a switch that selects and outputs output light from the plurality of optical amplifiers.
    An optical transmission system characterized in that the identification signals of the plurality of optical amplifiers are different from each other.
  8. 　複数の前記光増幅器に互いに異なる識別信号を出力するように制御する管理装置をさらに備えたことを特徴とする請求項７記載の光伝送システム。 The optical transmission system according to claim 7, further comprising a management device for controlling the plurality of optical amplifiers to output different identification signals.
  9. 　信号光を光増幅する光増幅器における光増幅方法であって、
    　前記光増幅器を識別する識別信号によって光増幅用の励起光を変調する駆動ステップと、
    　前記駆動ステップから出力される前記励起光を用いて前記信号光を光増幅し、出力光として出力する光増幅ステップと、
    　前記出力光と伝搬方向が逆となる戻り光を検出し、前記戻り光に自光増幅器の前記識別信号が含まれている場合に、前記励起光の出力レベルを下げる制御を行う検出ステップと
    　を備えた光増幅方法。     It is an optical amplification method in an optical amplifier that photoamplifies signal light.
    A drive step that modulates the excitation light for optical amplification with an identification signal that identifies the optical amplifier,
    An optical amplification step in which the signal light is photo-amplified using the excitation light output from the drive step and output as output light.
    A detection step of detecting a return light whose propagation direction is opposite to that of the output light and controlling the output level of the excitation light when the return light includes the identification signal of the self-optical amplifier. Provided optical amplification method.
PCT/JP2019/045919 2019-11-25 2019-11-25 Light amplifier, light transmission system, and light amplification method WO2021106031A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0927975A (en) * 1995-07-12 1997-01-28 Nippon Telegr & Teleph Corp <Ntt> Optical cross connect device
US5940209A (en) * 1997-03-18 1999-08-17 Lucent Technologies Inc. Interactive optical fiber amplifier, system and method
WO2004045116A1 (en) * 2002-11-13 2004-05-27 Fujitsu Limited Device for adequately regulating power of optical signal
JP2005019567A (en) * 2003-06-24 2005-01-20 Fujitsu Ltd Optical fiber amplifier and method for detecting disconnection of optical output connector

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0927975A (en) * 1995-07-12 1997-01-28 Nippon Telegr & Teleph Corp <Ntt> Optical cross connect device
US5940209A (en) * 1997-03-18 1999-08-17 Lucent Technologies Inc. Interactive optical fiber amplifier, system and method
WO2004045116A1 (en) * 2002-11-13 2004-05-27 Fujitsu Limited Device for adequately regulating power of optical signal
JP2005019567A (en) * 2003-06-24 2005-01-20 Fujitsu Ltd Optical fiber amplifier and method for detecting disconnection of optical output connector

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