WO2022228136A1 - 一种光功率调节系统和光功率调节装置 - Google Patents

一种光功率调节系统和光功率调节装置 Download PDF

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Publication number
WO2022228136A1
WO2022228136A1 PCT/CN2022/086738 CN2022086738W WO2022228136A1 WO 2022228136 A1 WO2022228136 A1 WO 2022228136A1 CN 2022086738 W CN2022086738 W CN 2022086738W WO 2022228136 A1 WO2022228136 A1 WO 2022228136A1
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optical
optical power
mmi
power adjustment
input
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PCT/CN2022/086738
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English (en)
French (fr)
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黄林博杰
潘超
张楷
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华为技术有限公司
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Priority to EP22794607.6A priority Critical patent/EP4325744A1/en
Publication of WO2022228136A1 publication Critical patent/WO2022228136A1/zh
Priority to US18/496,264 priority patent/US20240056188A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0121—Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/21—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  by interference
    • G02F1/217—Multimode interference type
    • 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
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
    • H01S3/1001—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by controlling the optical pumping
    • 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
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2581—Multimode transmission
    • 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
    • H04B10/29—Repeaters
    • H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
    • H04B10/293—Signal power control
    • H04B10/294—Signal power control in a multiwavelength system, e.g. gain equalisation
    • 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
    • H04B10/50—Transmitters
    • H04B10/564—Power control
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/50—Phase-only modulation
    • 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
    • H01S3/06754—Fibre amplifiers
    • 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
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094065—Single-mode pumping
    • 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
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094069—Multi-mode pumping
    • 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
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/1601—Solid materials characterised by an active (lasing) ion
    • H01S3/1603—Solid materials characterised by an active (lasing) ion rare earth
    • H01S3/1608—Solid materials characterised by an active (lasing) ion rare earth erbium

Definitions

  • the present application relates to the field of optical communications, and in particular, to an optical power adjustment system and an optical power adjustment device.
  • Erbium-Doped Fiber Amplifier can compensate for the loss caused by fiber link, and is used in long-distance optical communication, wavelength selective switch (WSS), programmable optical filter and other high link loss applications important role in the scene.
  • the pump light source is an essential part of the EDFA, and the power of the pump light affects the gain of the erbium-doped fiber amplifier.
  • the price of single-mode pump light source is more expensive, and the price of multi-mode pump light source is cheap.
  • the light output by the multi-mode pump light source cannot be directly applied to EDFA due to the existence of multiple transverse modes. Generally, it needs to be demultiplexed into multiple single-mode lights before outputting.
  • a current method is to first equalize the optical powers of different modes output by the multi-mode pump light source through a mode scrambler. Furthermore, the light of different modes output by the multi-mode pump light source is converted into the fundamental mode by the mode demultiplexer, and then output from a plurality of single-mode fibers respectively. However, the mode scrambler balances the optical power of different modes by bending the optical fiber. This method has poor adjustment accuracy. If the number of fundamental mode optical signals after mode demultiplexing is large, it is difficult to Ensure that the output optical power of each single-mode fiber is the same.
  • the embodiments of the present application provide an optical power adjustment system and an optical power adjustment device.
  • the mode demultiplexer can convert N channels of transverse mode optical signals output by a multi-mode light source into N channels of fundamental mode optical signals, and the optical power adjustment device can make The power of each fundamental mode optical signal is the same, the power adjustment accuracy is higher, and the applicability is wider.
  • the present application provides an optical power adjustment system.
  • the optical power adjustment system includes: a multi-mode light source, a mode demultiplexer and an optical power adjustment device.
  • the output port of the multi-mode light source is connected to the input port of the mode demultiplexer, and the output port of the mode demultiplexer is connected to the input port of the optical power adjustment device.
  • the multimode light source is used to output multimode optical signals.
  • the mode demultiplexer is used to convert N channels of transverse mode optical signals into N channels of fundamental mode optical signals, and output N channels of fundamental mode optical signals.
  • the optical power adjustment device includes M optical power adjustment modules and a control device, each optical power adjustment module includes a plurality of phase shifters, and the control device is electrically connected with the M optical power adjustment modules.
  • the M optical power adjustment modules are arranged in sequence from the input port of the optical power adjustment device to the output port of the optical power adjustment device, and the M optical power adjustment modules are connected together in series.
  • the Kth optical power adjustment module in the optical power adjustment device includes 2K-1 multi-mode interferometer MMIs, each MMI includes 2M-K+1 input ports and 2M-K+1 output ports, 1 ⁇ K ⁇ M.
  • the I-th input port or the 2M-K+1-I+1-th input port among the 2M-K+1 input ports is connected to a phase shifter, 1 ⁇ I ⁇ 2M-K+1.
  • the control device is used to adjust the phase shifter in the Kth optical power adjustment module, so that the optical signal input by the Ith input port of each MMI in the Kth optical power adjustment module is the same as the 2nd M-K+1-I
  • the phase difference of the optical signals input to the +1 input port is 0 or an integer multiple of 2 ⁇ . Therefore, the output optical power of the I-th output port of each MMI in the K-th optical power adjustment module is the same as the output optical power of the 2M-K+1-I+1-th output port.
  • the optical power adjustment device includes a multi-stage optical power adjustment module and a control device.
  • the input and output ports of each stage of the optical power adjustment module can be divided into multiple groups of input and output ports in a pairwise manner. Each group of input and output ports corresponds to a phase shifter.
  • the control device can adjust each phase shifter so that the output optical power of each group of output ports of each stage of the optical power adjustment module is the same.
  • it will add some optical signals with the same optical power.
  • the above-mentioned power adjustment method can be used to make the power of each fundamental mode optical signal the same, the power adjustment accuracy is higher, and the applicability is wider. .
  • the optical power adjustment device includes a first optical power adjustment module and a second optical power adjustment module.
  • the first optical power adjustment module includes a first MMI, a first phase shifter and a second phase shifter.
  • the second optical power adjustment module includes a second MMI, a third MMI, a third phase shifter and a fourth phase shifter.
  • the second input port or the third input port of the first MMI is connected to the first phase shifter, the first input port or the fourth input port of the second MMI is connected to the second phase shifter, and the first input port of the second MMI It is connected with the first output port of the first MMI, the input second port of the second MMI is connected with the second output port of the first MMI, the first input port of the third MMI is connected with the third output port of the first MMI, and the first input port of the third MMI is connected with the third output port of the first MMI.
  • the second input port of the three MMIs is connected to the fourth output port of the first MMI
  • the third phase shifter is connected between the first input port of the second MMI and the first output port of the first MMI or the second output port of the second MMI
  • the fourth phase shifter is connected between the first input port of the third MMI and the third output port of the first MMI or between the second input port of the third MMI and the third MMI. between the fourth output port of an MMI.
  • the control device is used to adjust the first phase shifter, so that the phase difference between the optical signal input from the second input port of the first MMI and the optical signal input from the third input port of the first MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the second output port of the first MMI is made the same as the output optical power of the third output port of the first MMI.
  • the control device is used to adjust the second phase shifter, so that the phase difference between the optical signal input from the first input port of the first MMI and the optical signal input from the fourth input port of the first MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the first output port of the first MMI is made the same as the output optical power of the fourth output port of the first MMI.
  • the control device is used to adjust the third phase shifter, so that the phase difference between the optical signal input from the first input port of the second MMI and the optical signal input from the second input port of the second MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the first output port of the second MMI is made the same as the output optical power of the second output port of the second MMI.
  • the control device is used to adjust the fourth phase shifter, so that the phase difference between the optical signal input from the first input port of the third MMI and the optical signal input from the second input port of the third MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the first output port of the third MMI is made the same as the output optical power of the second output port of the third MMI.
  • a minimal structure for constituting the optical power adjustment device is provided, which enhances the practicability of the present solution.
  • the multi-mode interference region length of all MMIs in each optical power conditioning module is 3L ⁇ /2, where L ⁇ is the beat length of the two lowest-order modes in the MMI waveguide.
  • L ⁇ is the beat length of the two lowest-order modes in the MMI waveguide.
  • the length of the multi-mode interference region is 3L ⁇ /2.
  • the length of the multimode interference region of the N ⁇ N optical coupler is all 3L ⁇ /N. It can be seen that the NxN MMI provided by this application is different from the NxN optical coupler.
  • the NxN optical coupler can only be used in the scenario where the input N-path light is incoherent light, while the NxN MMI provided by this application It can be applied to the scenario of converting multi-mode optical signals into N-channel coherent single-mode optical signals, which enhances the practicability of this solution.
  • the lengths of the multimode interference regions of the MMI in different optical power adjustment modules are different, which improves the flexibility of the solution.
  • the Kth optical power adjustment module further includes a plurality of optical beam splitters
  • the control device includes M control modules.
  • the 2M-K+1 input ports of each MMI in the Kth optical power adjustment module are respectively connected to the first output ports of the 2M-K+1 optical beam splitters.
  • the second output ports are all connected to the Kth control module, and the Kth control module is respectively electrically connected to each phase shifter in the Kth optical power adjustment module.
  • Each optical beam splitter is used to split the input optical signal, one of the split optical signals is output to the MMI corresponding to each optical beam splitter, and the other split optical signal is output to the Kth optical signal control module.
  • the Kth control module is used to detect the input optical signal, and adjust each phase shifter in the Kth optical power adjustment module according to the detection result.
  • a method for the control module to detect the optical signal is provided.
  • the control module is specifically used to detect each optical signal input to the MMI, and then adjust the corresponding phase shifter according to the detection result, which realizes automation ground adjustment.
  • the Kth control module includes 2M-K couplers, 2M-K photodetectors, and 2M-K phase control units.
  • the I-th input port is connected to the first output port of the I-th optical beam splitter.
  • the 2M-K+1-I+1th input port is connected to the first output port of the 2M-K+1-I+1th optical beam splitter.
  • the second output port of the I-th optical beam splitter and the second output port of the 2M-K+1-I+1-th optical beam splitter are connected to the input port of the J-th coupler, 1 ⁇ J ⁇ 2M- K.
  • the Jth coupler output port is connected to the Jth photodetector input port.
  • the output port of the J-th photodetector is electrically connected to the input port of the phase control unit.
  • the output port of the phase control unit is electrically connected to each phase shifter in the Kth optical power adjustment module.
  • the Jth coupler is used to couple the input optical signal.
  • the J-th photodetector is used to detect the coupled optical signal.
  • the phase control unit is used to adjust the I-th phase shifter in the K-th optical power adjustment module according to the detection result of the J-th photodetector, the I-th phase-shifter and the I-th input port or the 2M-K+ 1-I+1 input port connections.
  • a specific structure of the control module is provided. If the two optical signals input to the MMI are in the same phase, interference phase expansion will occur. At this time, the optical power detected by the optical detector is the largest.
  • the phase shifter can realize that the phase difference of the two optical signals input to the MMI is an integer multiple of 0 or 2 ⁇ , which improves the practical value of the
  • the Kth optical power adjustment module further includes a plurality of optical beam splitters
  • the control device includes M control modules.
  • the 2M-K+1 output ports of each MMI in the Kth optical power adjustment module are respectively connected to the input ports of the 2M-K+1 optical beam splitters, and the first The output ports are connected to the input ports of the 2K MMIs in the K+1th optical power adjustment module, and the second output ports of the 2M-K+1 optical beam splitters are all connected to the Kth control module, and the Kth control module It is respectively electrically connected with each phase shifter in the Kth optical power adjustment module.
  • Each beam splitter is used to split the incoming optical signal.
  • One of the split optical signals is output to the MMI corresponding to each beam splitter in the K+1 th optical power adjustment module, and the other split optical signal is output to the K th control module.
  • the Kth control module is used to detect the input optical signal, and adjust each phase shifter in the Kth optical power adjustment module according to the detection result.
  • another method for the control module to detect the optical signal is provided.
  • the control module is specifically used to detect each optical signal output by the MMI, and then adjust the corresponding phase shifter according to the detection result, so as to realize Automatically adjust and enhance the flexibility of the scheme.
  • the Kth control module includes 2M-K+1 photodetectors and 2M-K phase control units.
  • the second output ports of the 2M-K+1 optical beam splitters are connected to the input ports of the 2M-K+1 photodetectors, and the output ports of the 2M-K+1 photodetectors are all connected to the input ports of the phase control unit. Electrically connected, the output port of the phase control unit is electrically connected to each phase shifter in the Kth optical power adjustment module.
  • the I-th optical detector is used to detect the input optical signal, and the input port of the I-th optical detector is connected to the second output port of the I-th optical beam splitter.
  • the 2M-K+1-I+1 photodetector is used to detect the input optical signal, and the input port of the 2M-K+1-I+1 photodetector is connected to the 2M-K+1-I+1
  • the second output port of the optical beam splitter is connected.
  • the phase control unit is used to adjust the first phase shifter in the Kth optical power adjustment module according to the detection results of the first photodetector and the 2nd M-K+1-1+1 photodetector, the first The phase shifter is connected to the I-th input port or the 2M-K+1-I+1-th input port.
  • Each photodetector is used to detect the incoming optical signal.
  • the phase control unit is configured to adjust each phase shifter in the Kth optical power adjustment module according to the detection result of each photodetector.
  • a specific structure of the control module is provided. If the power of the two optical signals output by the MMI is the same, the difference between the optical powers detected by the two photodetectors is the smallest, and the phase shift is adjusted based on this principle. The power of the two optical signals output by the MMI can be the same. Different from the above-mentioned embodiment of adjusting the phase shifter according to the principle of interference phase expansion, the embodiment of the present solution is expanded.
  • the multi-mode light source is a multi-mode pump light source
  • the optical signal output by the optical power adjustment device is used to inject into the erbium-doped fiber.
  • the present application is particularly applicable to EDFA, and the optical power adjustment system is easy to integrate and has low cost.
  • the mode demultiplexer may be a demultiplexer in the form of an optical fiber, such as a photonic lantern or the like.
  • the mode demultiplexer may also be a demultiplexer in the form of a waveguide, such as a planar optical waveguide (PLC) demultiplexer, a silicon optical mode demultiplexer, and the like.
  • the mode demultiplexer may also be a spatial demultiplexer, such as a spatial optical mode demultiplexer based on a phase mask, etc., which improves the scalability of the solution.
  • the output port of the multimode light source is connected to the input port of the mode demultiplexer through a multimode fiber, and the output port of the mode demultiplexer is connected to the optical power through N single mode fibers or N waveguides
  • the connection of the input port of the adjustment device enriches the implementation of the solution.
  • the present application provides an optical power adjustment device.
  • the optical power adjustment device includes M optical power adjustment modules and a control device, where M is an integer greater than 1.
  • M is an integer greater than 1.
  • Each optical power adjustment module includes a plurality of phase shifters, and the control device is electrically connected to the M optical power adjustment modules.
  • the M optical power adjustment modules are arranged in sequence from the input port of the optical power adjustment device to the output port of the optical power adjustment device, and the M optical power adjustment modules are connected together in series.
  • the Kth optical power adjustment module in the optical power adjustment device includes 2K-1 multi-mode interferometer MMIs, each MMI includes 2M-K+1 input ports and 2M-K+1 output ports, 1 ⁇ K ⁇ M.
  • the first input port or the 2M-K+1-I+1 input port among the 2M-K+1 input ports is connected to a phase shifter, 1 ⁇ I ⁇ 2M-K+1.
  • the control device is used to adjust the phase shifter in the Kth optical power adjustment module, so that the optical signal input by the Ith input port of each MMI in the Kth optical power adjustment module is the same as the 2nd M-K+1-I
  • the phase difference of the optical signals input to the +1 input port is 0 or an integer multiple of 2 ⁇ . Therefore, the output optical power of the I-th output port of each MMI in the K-th optical power adjustment module is the same as the output optical power of the 2M-K+1-I+1-th output port.
  • the optical power adjustment device includes a first optical power adjustment module and a second optical power adjustment module.
  • the first optical power adjustment module includes a first MMI, a first phase shifter and a second phase shifter.
  • the second optical power adjustment module includes a second MMI, a third MMI, a third phase shifter and a fourth phase shifter.
  • the second input port or the third input port of the first MMI is connected to the first phase shifter, the first input port or the fourth input port of the second MMI is connected to the second phase shifter, and the first input port of the second MMI It is connected with the first output port of the first MMI, the input second port of the second MMI is connected with the second output port of the first MMI, the first input port of the third MMI is connected with the third output port of the first MMI, and the first input port of the third MMI is connected with the third output port of the first MMI.
  • the second input port of the three MMIs is connected to the fourth output port of the first MMI
  • the third phase shifter is connected between the first input port of the second MMI and the first output port of the first MMI or the second output port of the second MMI
  • the fourth phase shifter is connected between the first input port of the third MMI and the third output port of the first MMI or between the second input port of the third MMI and the third MMI. between the fourth output port of an MMI.
  • the control device is used to adjust the first phase shifter, so that the phase difference between the optical signal input from the second input port of the first MMI and the optical signal input from the third input port of the first MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the second output port of the first MMI is made the same as the output optical power of the third output port of the first MMI.
  • the control device is used to adjust the second phase shifter, so that the phase difference between the optical signal input from the first input port of the first MMI and the optical signal input from the fourth input port of the first MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the first output port of the first MMI is made the same as the output optical power of the fourth output port of the first MMI.
  • the control device is used to adjust the third phase shifter, so that the phase difference between the optical signal input from the first input port of the second MMI and the optical signal input from the second input port of the second MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the first output port of the second MMI is made the same as the output optical power of the second output port of the second MMI.
  • the control device is used to adjust the fourth phase shifter, so that the phase difference between the optical signal input from the first input port of the third MMI and the optical signal input from the second input port of the third MMI is 0 or an integer multiple of 2 ⁇ , and The output optical power of the first output port of the third MMI is made the same as the output optical power of the second output port of the third MMI.
  • a minimal structure for constituting the optical power adjustment device is provided, which enhances the practicability of the present solution.
  • the multi-mode interference region length of all MMIs in each optical power conditioning module is 3L ⁇ /2, where L ⁇ is the beat length of the two lowest-order modes in the MMI waveguide.
  • L ⁇ is the beat length of the two lowest-order modes in the MMI waveguide.
  • the length of the multi-mode interference region is 3L ⁇ /2.
  • the length of the multimode interference region of the N ⁇ N optical coupler is all 3L ⁇ /N. It can be seen that the NxN MMI provided by this application is different from the NxN optical coupler.
  • the NxN optical coupler can only be used in the scenario where the input N-path light is incoherent light, while the NxN MMI provided by this application It can be applied to the scenario of converting multi-mode optical signals into N-channel coherent single-mode optical signals, which enhances the practicability of this solution.
  • the lengths of the multimode interference regions of the MMI in different optical power adjustment modules are different, which improves the flexibility of the solution.
  • the Kth optical power adjustment module further includes a plurality of optical beam splitters
  • the control device includes M control modules.
  • the 2M-K+1 input ports of each MMI in the Kth optical power adjustment module are respectively connected to the first output ports of the 2M-K+1 optical beam splitters.
  • the second output ports are all connected to the Kth control module, and the Kth control module is respectively electrically connected to each phase shifter in the Kth optical power adjustment module.
  • Each optical beam splitter is used to split the input optical signal, one of the split optical signals is output to the MMI corresponding to each optical beam splitter, and the other split optical signal is output to the Kth optical signal control module.
  • the Kth control module is used to detect the input optical signal, and adjust each phase shifter in the Kth optical power adjustment module according to the detection result.
  • a method for the control module to detect the optical signal is provided.
  • the control module is specifically used to detect each optical signal input to the MMI, and then adjust the corresponding phase shifter according to the detection result, which realizes automation ground adjustment.
  • the Kth control module includes 2M-K couplers, 2M-K photodetectors, and 2M-K phase control units.
  • the I-th input port is connected to the first output port of the I-th optical beam splitter.
  • the 2M-K+1-I+1th input port is connected to the first output port of the 2M-K+1-I+1th optical beam splitter.
  • the second output port of the I-th optical beam splitter and the second output port of the 2M-K+1-I+1-th optical beam splitter are connected to the input port of the J-th coupler, 1 ⁇ J ⁇ 2M- K.
  • the Jth coupler output port is connected to the Jth photodetector input port.
  • the output port of the J-th photodetector is electrically connected to the input port of the phase control unit.
  • the output port of the phase control unit is electrically connected with each phase shifter in the Kth optical power adjustment module.
  • the Jth coupler is used to couple the input optical signal.
  • the J-th photodetector is used to detect the coupled optical signal.
  • the phase control unit is used to adjust the I-th phase shifter in the K-th optical power adjustment module according to the detection result of the J-th photodetector, the I-th phase-shifter and the I-th input port or the 2M-K+ 1-I+1 input port connections.
  • a specific structure of the control module is provided. If the two optical signals input to the MMI are in the same phase, interference phase expansion will occur. At this time, the optical power detected by the optical detector is the largest.
  • the phase shifter can realize that the phase difference of the two optical signals input to the MMI is an integer multiple of 0 or 2 ⁇ , which improves the practical value of the
  • the Kth optical power adjustment module further includes a plurality of optical beam splitters
  • the control device includes M control modules.
  • the 2M-K+1 output ports of each MMI in the Kth optical power adjustment module are respectively connected to the input ports of the 2M-K+1 optical beam splitters, and the first The output ports are connected to the input ports of the 2K MMIs in the K+1th optical power adjustment module, and the second output ports of the 2M-K+1 optical beam splitters are all connected to the Kth control module, and the Kth control module It is respectively electrically connected with each phase shifter in the Kth optical power adjustment module.
  • Each beam splitter is used to split the incoming optical signal.
  • One of the split optical signals is output to the MMI corresponding to each beam splitter in the K+1 th optical power adjustment module, and the other split optical signal is output to the K th control module.
  • the Kth control module is used to detect the input optical signal, and adjust each phase shifter in the Kth optical power adjustment module according to the detection result.
  • another method for the control module to detect the optical signal is provided.
  • the control module is specifically used to detect each optical signal output by the MMI, and then adjust the corresponding phase shifter according to the detection result, so as to realize Automatically adjust and enhance the flexibility of the scheme.
  • the Kth control module includes 2M-K+1 photodetectors and 2M-K phase control units.
  • the second output ports of the 2M-K+1 optical beam splitters are connected to the input ports of the 2M-K+1 photodetectors, and the output ports of the 2M-K+1 photodetectors are all connected to the input ports of the phase control unit. Electrically connected, the output port of the phase control unit is electrically connected to each phase shifter in the Kth optical power adjustment module.
  • the I-th optical detector is used to detect the input optical signal, and the input port of the I-th optical detector is connected to the second output port of the I-th optical beam splitter.
  • the 2M-K+1-I+1 photodetector is used to detect the input optical signal, and the input port of the 2M-K+1-I+1 photodetector is connected to the 2M-K+1-I+1
  • the second output port of the optical beam splitter is connected.
  • the phase control unit is used to adjust the first phase shifter in the Kth optical power adjustment module according to the detection results of the first photodetector and the 2nd M-K+1-1+1 photodetector, the first The phase shifter is connected to the I-th input port or the 2M-K+1-I+1-th input port.
  • Each photodetector is used to detect the incoming optical signal.
  • the phase control unit is configured to adjust each phase shifter in the Kth optical power adjustment module according to the detection result of each photodetector.
  • a specific structure of the control module is provided. If the power of the two optical signals output by the MMI is the same, the difference between the optical powers detected by the two photodetectors is the smallest, and the phase shift is adjusted based on this principle. The power of the two optical signals output by the MMI can be the same. Different from the above-mentioned embodiment of adjusting the phase shifter according to the principle of interference phase expansion, the embodiment of the present solution is expanded.
  • an optical power adjustment system can convert N channels of transverse mode optical signals output by the multi-mode light source into N channels of fundamental mode optical signals. After that, the N fundamental mode optical signals are input to the optical power adjustment device.
  • the optical power adjustment device includes a multi-level optical power adjustment module and a control device. Wherein, the input and output ports of each stage of the optical power adjustment module can be divided into multiple groups of input and output ports in a pairwise manner. Each group of input and output ports corresponds to a phase shifter.
  • the control device can adjust each phase shifter so that the output optical power of each group of output ports of each stage of the optical power adjustment module is the same.
  • the optical power adjustment module After each stage of the optical power adjustment module is adjusted, it will add some optical signals with the same optical power.
  • the optical powers of the N optical signals output by the optical power adjustment device are the same. It should be understood that regardless of the number of fundamental mode optical signals after mode demultiplexing, the above-mentioned power adjustment method can be used to make the power of each fundamental mode optical signal the same, the power adjustment accuracy is higher, and the applicability is wider. .
  • FIG. 1 is a schematic structural diagram of an optical power adjustment system provided by an embodiment of the present application
  • FIG. 2 is a schematic structural diagram of an optical power adjustment device provided by an embodiment of the present application.
  • FIG. 3 is another schematic structural diagram of an optical power adjustment device provided by an embodiment of the present application.
  • FIG. 4(a) is another schematic structural diagram of the optical power adjustment device provided by the embodiment of the present application.
  • FIG. 4(b) is a schematic structural diagram of a control module provided by an embodiment of the present application.
  • Fig. 5(a) is another schematic structural diagram of the optical power adjustment device provided by the embodiment of the present application.
  • Fig. 5(b) is another schematic structural diagram of the control module provided by the embodiment of the present application.
  • FIG. 6 is another schematic structural diagram of the optical power adjustment device provided by the embodiment of the present application.
  • the embodiments of the present application provide an optical power adjustment system and an optical power adjustment device.
  • the mode demultiplexer can convert N channels of transverse mode optical signals output by a multi-mode light source into N channels of fundamental mode optical signals, and the optical power adjustment device can make The power of each fundamental mode optical signal is the same, the power adjustment accuracy is higher, and the applicability is wider.
  • the optical power adjustment system provided by the present application is mainly applied to a scenario where power equalization is performed on a plurality of single-mode optical signals after demultiplexing a multi-mode optical signal into a plurality of single-mode optical signals.
  • the optical power adjustment system can be specifically applied to an Erbium-Doped Fiber Amplifier (EDFA).
  • EDFA Erbium-Doped Fiber Amplifier
  • the pump light source is an essential part of the EDFA, and the power of the pump light affects the gain of the erbium-doped fiber amplifier.
  • the price of single-mode pump light source is more expensive, and the price of multi-mode pump light source is cheap.
  • the light output by the multi-mode pump light source cannot be directly applied to EDFA due to the existence of multiple transverse modes.
  • the present application provides an optical power adjustment system for adjusting the power of each fundamental mode optical signal to be the same.
  • the optical power adjustment system provided by the present application will be introduced below. It should be noted that the solid lines in the following drawings represent the transmission paths of optical signals, and the broken lines represent the transmission paths of electrical signals.
  • FIG. 1 is a schematic structural diagram of an optical power adjustment system provided by an embodiment of the present application.
  • the optical power adjustment system includes: a multi-mode light source 10 , a mode demultiplexer 20 and an optical power adjustment device 30 .
  • the output port of the multi-mode light source 10 is connected to the input port of the mode demultiplexer 20, and the output port of the mode demultiplexer 20 is connected to the input port of the optical power adjustment device 30.
  • the optical power adjustment device includes M optical power adjustment modules and a control device, the M optical power adjustment modules are sequentially arranged from the input port of the optical power adjustment device to the output port of the optical power adjustment device, and the M optical power adjustment modules are connected in series. Together, M is an integer greater than one.
  • the control device is electrically connected with the M optical power adjustment modules.
  • N the number of transverse modes optical signals
  • the light field output by the multi-mode light source 10 has both multiple transverse modes and multiple longitudinal modes, and the influence of the multiple longitudinal modes is not great for the pumping of the EDFA.
  • EDFA uses single-mode erbium-doped fiber, which cannot support high-order transverse modes, and multiple transverse modes will cause waste of pump light power.
  • the N channels of transverse mode optical signals into N channels of fundamental mode optical signals through the mode demultiplexer 20 , and output the N channels of fundamental mode optical signals to the optical power adjustment device 30 .
  • the powers of the N optical signals output by the optical power adjustment device 30 are the same. It should be understood that, in practical applications, the powers of the N-path optical signals output by the optical power adjustment device 30 can be considered to be the same as long as the powers are within an acceptable error range.
  • the multi-mode light source 10 may be a multi-mode pumping light source, and the multi-mode light source 10 is connected to the mode demultiplexer 20 through a multi-mode optical fiber.
  • the N-path optical signals output by the optical power adjusting device 30 are respectively used to inject into the corresponding erbium-doped fibers.
  • the mode demultiplexer 20 may be a demultiplexer in the form of an optical fiber, such as a photonic lantern or the like.
  • the mode demultiplexer 20 may also be a demultiplexer in the form of a waveguide, such as a planar optical waveguide (Planar optical waveguide, PLC) demultiplexer, a silicon optical mode demultiplexer, and the like.
  • the mode demultiplexer 20 may also be a spatial demultiplexer, such as a spatial optical mode demultiplexer based on a phase mask and the like. It should be understood that if the mode demultiplexer 20 is a demultiplexer in the form of an optical fiber, then the mode demultiplexer 20 is connected to the optical power adjustment device 30 through N single-mode fibers, and M optical fibers in the optical power adjustment device 30 The power conditioning modules are also connected in series through optical fibers.
  • the mode demultiplexer 20 is a demultiplexer in the form of a waveguide, then the mode demultiplexer 20 is connected to the optical power adjustment device 30 through N waveguides, and the M optical power adjustment modules in the optical power adjustment device 30 also pass through The waveguides are connected in series.
  • FIG. 2 is a schematic structural diagram of an optical power adjustment device provided by an embodiment of the present application.
  • each optical power adjustment module includes at least one multimode interferometer (MultiMode Inferometer, MMI) and multiple phase shifters.
  • MMI MultiMode Inferometer
  • the number of MMIs and the number of phase shifters in each optical power adjustment module is determined by the order of the optical power adjustment modules.
  • the input port of the first optical power adjustment module is the input port of the optical power adjustment device 30
  • the output port of the Mth optical power adjustment module is the output port of the optical power adjustment device 30 .
  • the Kth optical power adjustment module includes 2K-1 multi-mode interferometer MMIs, each MMI includes 2M-K+1 input ports and 2M-K+1 output ports, 1 ⁇ K ⁇ M.
  • the first input port or the 2M-K+1-I+1 input port among the 2M-K+1 input ports is connected to a phase shifter, 1 ⁇ I ⁇ 2M-K+1.
  • the control device adjusts each phase shifter in the Kth optical power adjustment module, so that the optical signal input by the Ith input port of each MMI in the Kth optical power adjustment module is the same as the 2nd M-K+1-I
  • the phase difference of the optical signals input to the +1 input port is 0 or an integer multiple of 2 ⁇ .
  • the output optical power of the I-th output port of each MMI in the K-th optical power adjustment module can be made the same as the output optical power of the 2M-K+1-I+1-th output port.
  • Each optical power adjustment module performs power adjustment according to the above-mentioned manner, which can ensure that the optical powers of the N optical signals output by the Mth optical power adjustment module are the same.
  • the length of the multi-mode interference region of all MMIs in each optical power adjustment module is 3L ⁇ /2, and L ⁇ is the beat length of the two lowest-order modes in the MMI waveguide. Moreover, the lengths of the multimode interference regions of the MMI in different optical power adjustment modules are different.
  • FIG. 3 is another schematic structural diagram of an optical power adjustment device provided by an embodiment of the present application.
  • the optical power adjustment device 30 includes an optical power adjustment module 301 , an optical power adjustment module 302 and a control device 303 .
  • the optical power adjustment module 301 includes a 4 ⁇ 4 MMI 301a, a phase shifter 301b and a phase shifter 301c.
  • the optical power adjustment module 302 includes a 2 ⁇ 2 MMI 302a, a 2 ⁇ 2 MMI 302b, a phase shifter 301c and a phase shifter 301d. It should be understood that the positions of the phase shifters shown in FIG.
  • the input port 1 or the input port 4 of the MMI 301a is used for connecting the phase shifter 301c
  • the input port 2 or the input port 3 of the MMI 301a is used for connecting the phase shifter 301b.
  • Input port 1 or input port 2 of the MMI 302a is used to connect the phase shifter 302c.
  • Input port 1 or input port 2 of MMI 302b is used to connect phase shifter 302d.
  • the control device 303 adjusts the phase shifter 301b so that the phase difference of the optical signal input from the input port 2 and the input port 3 of the MMI 301a is an integer multiple of 0 or 2 ⁇ , thereby making the output port 2 of the MMI 301a and the output port 3 output
  • the optical power is the same.
  • the control device 303 adjusts the phase shifter 301c, so that the phase difference of the optical signal input by the input port 1 and the input port 4 of the MMI 301a is an integer multiple of 0 or 2 ⁇ , thereby making the output port 1 of the MMI 301a and the output port 4 output
  • the optical power is the same.
  • the control device 303 adjusts the phase shifter 302c so that the phase difference of the optical signal input by the input port 1 and the input port 2 of the MMI 302a is an integer multiple of 0 or 2 ⁇ , thereby making the output port 1 of the MMI 302a and the output port 2 output
  • the optical power is the same.
  • the control device 303 adjusts the phase shifter 302d so that the phase difference of the optical signal input by the input port 1 and the input port 2 of the MMI 302b is an integer multiple of 0 or 2 ⁇ , thereby making the output port 1 of the MMI 302b and the output port 2 output.
  • the optical power is the same.
  • the 4-channel optical signals input by the optical power adjustment module 301 can be divided into two groups. After adjustment, the output port 1 and the output port 4 output the same optical power, and the output port 2 and output port 3 output a group of optical powers. The optical power is the same. Then, the optical powers of the two sets of optical signals are adjusted to be consistent through the optical power adjustment module 302, and finally the optical powers of the four optical signals output by the optical power adjustment module 302 are the same.
  • the principle of adopting the above design method is described below.
  • E 1 a
  • a, b, c, d are the optical powers of the four inputs respectively
  • j is an imaginary number
  • the light fields of the four output ports of the MMI 301a are expressed as:
  • the output port 1 and the output port 2 of the MMI 301a are respectively connected to the input port 1 and the input port 2 of the MMI 302a, and by adjusting the phase shifter 302c, the phases of the two optical signals input to the input port of the MMI 302a are the same,
  • the transmission matrix of the MMI 302a is:
  • the output optical power of output port 1 and output port 2 of MMI 302a can be obtained as Similarly, the output optical powers of output port 1 and output port 2 of the MMI 302b are also both Thus, the power equalization of the four optical signals is realized.
  • the N ⁇ N MMI used in this application is different from the N ⁇ N optical coupler in the following points.
  • the NxN optical coupler can only be used when the input N channels of light are incoherent lights, and for the scenario where the multi-mode optical signal is converted into N channels of single-mode optical signals, the N channels of single-mode optical signals are coherent lights. , so the NxN optocoupler cannot be used directly to achieve optical power balance.
  • the NxN optical coupler it is necessary to adjust the phases of the input N channels of optical signals to be consistent so that the output optical powers of the N channels are the same.
  • the NxN optical coupler cannot guarantee that the phases of the input optical signals of the N channels are completely consistent.
  • the relative phase difference of the two optical signals can be detected, and the phases of the two input optical signals in this group can be adjusted to be consistent through the phase shifter.
  • the optical power balance of N outputs can be achieved through multiple cascaded optical power adjustment modules.
  • control device provided in the present application can realize the extraction of the phase difference of the two input optical signals, and control the phase shifter to adjust the phase of the input optical signals. That is to say, the optical power adjustment device provided by the present application realizes power adjustment automatically without manual control. Specifically, the present application provides a variety of implementations for detecting the phase difference through the control device, which are described below by taking the optical power adjustment device shown in FIG. 3 as an example.
  • the first implementation is a first implementation:
  • FIG. 4( a ) is another schematic structural diagram of the optical power adjustment device provided by the embodiment of the present application.
  • the optical power adjustment module 301 and the optical power adjustment module 302 further include a plurality of optical beam splitters respectively.
  • the control device 303 includes a control module 1 and a control module 2 , wherein the control module 1 is used to control the phase shifter in the optical power adjustment module 301 , and the control module 2 is used to control the phase shifter in the optical power adjustment module 302 .
  • each optical beam splitter is used to split each optical signal input to the MMI 301a, and one of the split optical signals is output to the MMI 301a, and the split The next optical signal is output to the control module 1 .
  • the same is also applicable to the optical beam splitter in the optical power adjustment module 302, and details are not repeated here. It should be noted that this application does not limit the splitting ratio of each optical beam splitter. As a preferred implementation, most of the split optical signals should be output to the corresponding MMI, and a small part of the split optical signals should be output to the corresponding MMI. output to the corresponding control module.
  • FIG. 4( b ) is a schematic structural diagram of a control module provided by an embodiment of the present application.
  • the control module 1 includes a coupler 303a, a photodetector 303b and a phase control unit 303c.
  • the optical beam splitter connected to the input port 1 of the MMI 301a is also connected to the coupler 303a, and the optical beam splitter connected to the input port 4 of the MMI 301a is also connected to the coupler 303a.
  • the coupler 303a is used to couple the input optical signal.
  • the photodetector 303b is used to detect the coupled optical signal.
  • the phase control unit 303c is used to adjust the phase shifter 301c according to the detection result output by the photodetector 303b. Specifically, the phase control unit 303c can gradually adjust the voltage output by the phase control unit 303c, so that the phase value of the phase shifter 301c scans in the range of 0-2 ⁇ . During this process, the optical detector 303b continues to perform power detection on the optical signal output by the coupler 303a. The phase control unit 303c can continuously read the voltage output by the photodetector 303b. It should be understood that if the phase difference of the two optical signals input to the coupler 303a is 0 or an integer multiple of 2 ⁇ , the two optical signals will interfere and expand.
  • the output voltage is also the largest, and the phase control unit 303c can maintain the current output voltage, so that the phase difference between the two optical signals input to the coupler 303a is 0 or an integer multiple of 2 ⁇ .
  • the output optical powers of the output port 1 and the output port 4 of the MMI 301a are the same.
  • FIG. 4(b) only shows a part of the corresponding phase shifter 301c in the control module 1, and the structure of the corresponding phase shifter 301b is also similar to that shown in FIG. 4(b). Repeat.
  • FIG. 5( a ) is another schematic structural diagram of the optical power adjustment device provided by the embodiment of the present application.
  • the optical power adjustment module 301 and the optical power adjustment module 302 further include a plurality of optical beam splitters respectively.
  • the control device 303 includes a control module 1 and a control module 2, wherein the control module 1 is used to control the phase shifter in the optical power adjustment module 301, and the control module 2 is used to control the phase shifter in the optical power adjustment module 302.
  • each beam splitter is used to split each optical signal output by the MMI 301a, and one of the split optical signals is output to the optical power adjustment module 302, The other optical signal after the split is output to the control module 1 .
  • the same is also applicable to the optical beam splitter in the optical power adjustment module 302, and details are not repeated here. It should be noted that this application does not limit the splitting ratio of each optical beam splitter. As a preferred implementation, most of the split optical signals should be output to the corresponding MMI, and a small part of the split optical signals should be output to the corresponding MMI. output to the corresponding control module.
  • FIG. 5(b) is another schematic structural diagram of the control module provided by the embodiment of the present application.
  • the control module 1 includes a photodetector 303d, a photodetector 303e and a phase control unit 303c.
  • the optical beam splitter connected to the output port 1 of the MMI 301a is also connected to the photodetector 303d, and the optical beam splitter connected to the output port 4 of the MMI 301a is also connected to the photodetector 303e.
  • the photodetector 303d and the photodetector 303e are respectively used to detect the respective input optical signals.
  • the phase control unit 303c is used to adjust the phase shifter 301c according to the detection results output by the photodetector 303d and the photodetector 303e. Specifically, the phase control unit 303c can gradually adjust the voltage output by the phase control unit 303c, so that the phase value of the phase shifter 301c scans in the range of 0-2 ⁇ . During this process, the phase control unit 303c can continuously read the voltages output by the photodetector 303d and the photodetector 303e, and calculate the difference between the two input voltages.
  • the phase control unit 303c can maintain the current output voltage, so that the output optical powers of the output port 1 and the output port 4 of the MMI 301a are the same.
  • FIG. 5(b) only shows a part of the corresponding phase shifter 301c in the control module 1, and the structure of the corresponding phase shifter 301b is also similar to that shown in FIG. 5(b). Repeat.
  • an optical power adjustment system can convert N channels of transverse mode optical signals output by the multi-mode light source into N channels of fundamental mode optical signals. After that, the N fundamental mode optical signals are input to the optical power adjustment device.
  • the optical power adjustment device includes a multi-level optical power adjustment module and a control device. Wherein, the input and output ports of each stage of the optical power adjustment module can be divided into multiple groups of input and output ports in a pairwise manner. Each group of input and output ports corresponds to a phase shifter.
  • the control device can adjust each phase shifter so that the output optical power of each group of output ports of each stage of the optical power adjustment module is the same.
  • the optical power adjustment module After each stage of the optical power adjustment module is adjusted, it will add some optical signals with the same optical power.
  • the optical powers of the N optical signals output by the optical power adjustment device are the same. It should be understood that regardless of the number of fundamental mode optical signals after mode demultiplexing, the above-mentioned power adjustment method can be used to make the power of each fundamental mode optical signal the same, the power adjustment accuracy is higher, and the applicability is wider. .
  • FIG. 6 is another schematic structural diagram of the optical power adjustment device provided by the embodiment of the present application.
  • each optical power adjustment module of the optical power adjustment device adopts the same N ⁇ N MMI.
  • the output port of the optical power adjustment module 301 and the input port of the optical power adjustment module 302 are not completely correspondingly connected according to the port numbers, but adopt a partially cross-connected manner.
  • the optical power adjustment module 301 is similar to the optical power adjustment module 301 in the embodiment shown in FIG. 3 , and details are not repeated here.
  • the structure of the optical power adjustment module 302 is mainly described below.
  • the output port 1 of the MMI 301a is connected with the input port 1 of the MMI 302a
  • the output port 2 of the MMI 301a is connected with the input port 2 of the MMI 302a
  • the output port 3 of the MMI 301a is connected with the input port 4 of the MMI 302a
  • the output port 4 of the MMI 301a is connected to the input port 3 of the MMI 302a. It should be understood that, for the MMI 302a, input port 1 and input port 4 are the same group of input ports, and input port 2 and input port 3 are the same group of input ports.
  • output port 3 and output port 4 of MMI 301a are cross-connected with input port 3 and input port 4 of MMI 302a, the input optical power of input port 1 and input port 3 of MMI 302a is the same, and input port 2 and input port 2 and input The input optical power of port 4 is the same. Then, the input port 1 or the input port 4 of the MMI 302a should be connected to the phase shifter 302b, so that the output optical power of the output port 1 or the output port 4 of the MMI 302a is the same after adjustment.
  • the input port 2 or the input port 3 of the MMI 302a should be connected to the phase shifter 302c, and after adjustment, the output optical power of the output port 2 or the output port 3 of the MMI 302a is the same. Ultimately, the output optical power of the four output ports of the MMI 302a is the same.
  • the specific power adjustment manner is similar to the manner introduced in the foregoing embodiment, and details are not described herein again.
  • connection mode shown in FIG. 6 can be understood as a connection mode in which the port 1 and the port 2 are directly connected, and the port 3 and the port 4 are crossed. In addition, based on the same design idea, it can also be a direct connection between port 1 and port 3, and a cross connection between port 2 and port 4, or a direct connection between port 3 and port 4, and a cross connection between port 1 and port 2. Or, port 2 and port 4 are directly connected, and port 1 and port 3 are cross-connected. It should be understood that, based on the design idea of the embodiment shown in FIG. 6 , the present application can also extend this implementation to a scenario where the number of optical power adjustment modules is greater than two, and details are not repeated here.
  • this embodiment of the present application also provides an optical power adjustment device, and the optical power adjustment device may be the optical power adjustment device described in any of the above-mentioned embodiments in FIGS. 1 to 6 .
  • the optical power adjustment device may be the optical power adjustment device described in any of the above-mentioned embodiments in FIGS. 1 to 6 .
  • FIG. 1 the relevant description of the embodiment shown in FIG. 6 will not be repeated here.

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Abstract

本申请实施例提供了一种光功率调节系统和光功率调节装置。光功率调节系统包括多模光源、模式解复用器和光功率调节装置。多模光源用于输出多模光信号，多模光信号包括N路横模光信号，N＝2 M，M为大于1的整数。模式解复用器用于将N路横模光信号转换为N路基模光信号，并输出N路基模光信号。光功率调节装置包括M个光功率调节模块和控制装置，每个光功率调节模块包括多个移相器，控制装置与M个光功率调节模块电连接。第K个光功率调节模块包括2 K-1个多模干涉器MMI，每个MMI的第I个输入端口或第2 M-K+1-I+1个输入端口连接一个移相器。控制装置用于调节第K个光功率调节模块中的移相器，以使得第I个输出端口的输出光功率与第2 M-K+1-I+1个输出端口的输出光功率相同。

Description

一种光功率调节系统和光功率调节装置
本申请要求于2021年4月30日提交中国国家知识产权局、申请号为202110485437.9、申请名称为“一种光功率调节系统和光功率调节装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光通信领域，尤其涉及一种光功率调节系统和光功率调节装置。
背景技术
掺铒光纤放大器(Erbium-Doped Fiber Amplifier，EDFA)可以补偿光纤链路带来的损耗，在长途光通信、波长选择开关(Wavelength selective switch，WSS)、可编程光滤波器等高链路损耗应用场景中起到至关重要的作用。泵浦光源是EDFA中必不可少的组成部分，泵浦光功率的大小影响着掺铒光纤放大器的增益。通常单模泵浦光源的价格较贵，而多模泵浦光源的价格便宜。但是多模泵浦光源输出的光由于存在多个横模，无法直接应用于EDFA，一般需要通过模式解复用为多个单模的光后再输出。
除此之外，由于多模激光器输出的多个模式的光功率可能是不同的，还需要保证模式解复用后的多个单模的光功率均衡才行。目前的一种方式是，先通过扰模器将多模泵浦光源输出的不同模式的光功率进行均衡。进而，通过模式解复用器将多模泵浦光源输出的不同模式的光都转换为基模，再分别从多根单模光纤中输出。但是，扰模器是通过对光纤进行弯曲等方式来对不同模式的光功率进行均衡的，这种方式的调节精度较差，如果模式解复用后的基模光信号数量较多，很难保证每根单模光纤输出的光功率相同。
发明内容
本申请实施例提供了一种光功率调节系统和光功率调节装置，模式解复用器可以将多模光源输出的N路横模光信号转换为N路基模光信号，通过光功率调节装置可以使得每一路基模光信号的功率相同，功率调节的精度更高，并且适用性更广。
第一方面，本申请提供了一种光功率调节系统。该光功率调节系统包括：多模光源、模式解复用器和光功率调节装置。其中，多模光源的输出端口与模式解复用器的输入端口连接，模式解复用器的输出端口与光功率调节装置的输入端口连接。多模光源用于输出多模光信号。多模光信号包括N路横模光信号，N＝2M，M为大于1的整数。模式解复用器用于将N路横模光信号转换为N路基模光信号，并输出N路基模光信号。光功率调节装置包括M个光功率调节模块和控制装置，每个光功率调节模块包括多个移相器，控制装置与M个光功率调节模块电连接。M个光功率调节模块从光功率调节装置的输入端口到光功率调节装置的输出端口依次排列，并且M个光功率调节模块串连在一起。光功率调节装置中的第K个光功率调节模块包括2K-1个多模干涉器MMI，每个MMI包括2M-K+1个输入端口和2M-K+1个输出端口，1≤K≤M。2M-K+1个输入端口中第I个输入端口或第2M-K+1-I+1个输入端口连接一个移相器，1 ≤I≤2M-K+1。控制装置用于调节第K个光功率调节模块中的移相器，以使得第K个光功率调节模块中每个MMI的第I个输入端口输入的光信号与第2M-K+1-I+1个输入端口输入的光信号的相位差为0或2π的整数倍。从而使得第K个光功率调节模块中每个MMI的第I个输出端口的输出光功率与第2M-K+1-I+1个输出端口的输出光功率相同。
在该实施方式中，光功率调节装置包括多级光功率调节模块和控制装置。其中，每级光功率调节模块的输入输出端口可以按两两一组的方式拆分成多组输入输出端口。每一组输入输出端口对应一个移相器。控制装置可以通过调节每个移相器，使得每一级光功率调节模块的每一组输出端口的输出光功率相同。按照一定的设计方式，每一级光功率调节模块完成调节后，都将增加部分光功率相同的光信号。以此类推，当所有的光功率调节模块都完成调节后，就可以保证光功率调节装置输出的N路光信号的光功率相同。应理解，无论模式解复用后的基模光信号数量有多少，都可以通过上述的功率调节方式，使得每一路基模光信号的功率相同，功率调节的精度更高，并且适用性更广。
在一些可能的实施方式中，光功率调节装置包括第一光功率调节模块和第二光功率调节模块。第一光功率调节模块包括第一MMI、第一移相器和第二移相器。第二光功率调节模块包括第二MMI、第三MMI、第三移相器和第四移相器。第一MMI的第二输入端口或第三输入端口与第一移相器连接，第二MMI的第一输入端口或第四输入端口与第二移相器连接，第二MMI的第一输入端口与第一MMI的第一输出端口连接，第二MMI的输入第二端口与第一MMI的第二输出端口连接，第三MMI的第一输入端口与第一MMI的第三输出端口连接，第三MMI的第二输入端口与第一MMI的第四输出端口连接，第三移相器连接在第二MMI的第一输入端口与第一MMI的第一输出端口之间或第二MMI的第二输入端口与第一MMI的第二输出端口之间，第四移相器连接在第三MMI的第一输入端口与第一MMI的第三输出端口之间或第三MMI的第二输入端口与第一MMI的第四输出端口之间。
控制装置用于调节第一移相器，以使得第一MMI的第二输入端口输入的光信号与第一MMI的第三输入端口输入的光信号的相位差为0或2π的整数倍，并使得第一MMI的第二输出端口的输出光功率与第一MMI的第三输出端口的输出光功率相同。控制装置用于调节第二移相器，以使得第一MMI的第一输入端口输入的光信号与第一MMI的第四输入端口输入的光信号的相位差为0或2π的整数倍，并使得第一MMI的第一输出端口的输出光功率与第一MMI的第四输出端口的输出光功率相同。控制装置用于调节第三移相器，以使得第二MMI的第一输入端口输入的光信号与第二MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得第二MMI的第一输出端口的输出光功率与第二MMI的第二输出端口的输出光功率相同。控制装置用于调节第四移相器，以使得第三MMI的第一输入端口输入的光信号与第三MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得第三MMI的第一输出端口的输出光功率与第三MMI的第二输出端口的输出光功率相同。在该实施方式中，提供了一种组成光功率调节装置的最小结构，增强了本方案的可实现性。
在一些可能的实施方式中，每个光功率调节模块中的所有MMI的多模干涉区长度都为3L π/2，L π为MMI波导中两个最低阶模式的拍长。在该实施方式中，无论N×N的MMI的输入输出端口数量是多少，其多模干涉区长度都为3L π/2。而N×N的光耦合器的多模干涉区长度都为3L π/N。可见，本申请提供的N×N的MMI与N×N的光耦合器不同，NxN光耦合器只能用 于输入的N路光是非相干光的场景，而本申请提供的N×N的MMI可应用于将多模光信号转化为N路相干的单模光信号的场景，增强了本方案的实用性。
在一些可能的实施方式中，不同光功率调节模块中MMI的多模干涉区长度不同，提高了本方案的灵活性。
在一些可能的实施方式中，第K个光功率调节模块还包括多个光分束器，控制装置包括M个控制模块。第K个光功率调节模块中每个MMI的2M-K+1个输入端口分别与2M-K+1个光分束器的第一输出端口连接，2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，第K个控制模块分别与第K个光功率调节模块中的每个移相器电连接。每个光分束器用于对输入的光信号进行分路，分路后的其中一路光信号输出至与每个光分束器对应的MMI，分路后的另一路光信号输出至第K个控制模块。第K个控制模块用于对输入的光信号进行检测，并根据检测的结果调节第K个光功率调节模块中的每个移相器。在该实施方式中，提供了一种控制模块对光信号进行检测的方式，控制模块具体用于对输入MMI的每一路光信号进行检测，再根据检测结果调节对应的移相器，实现了自动化地调节。
在一些可能的实施方式中，第K个控制模块包括2M-K个耦合器、2M-K个光探测器和2M-K相位控制单元。第I个输入端口与第I个光分束器的第一输出端口连接。第2M-K+1-I+1个输入端口与第2M-K+1-I+1个光分束器的第一输出端口连接。第I个光分束器的第二输出端口和第2M-K+1-I+1个光分束器的第二输出端口与第J个耦合器的输入端口连接，1≤J≤2M-K。第J个耦合器输出端口与第J个光探测的输入端口连接。第J个光探测器的输出端口与相位控制单元的输入端口电连接。相位控制单元的输出端口与第K个光功率调节模块中的每个移相器电连接。第J个耦合器用于对输入的光信号进行耦合。第J个光探测器用于对耦合后的光信号进行检测。相位控制单元用于根据第J个光探测器的检测结果调节第K个光功率调节模块中的第I个移相器，第I个移相器与第I个输入端口或第2M-K+1-I+1个输入端口连接。在该实施方式中，提供了一种控制模块的具体结构，如果输入MMI的两路光信号同相位，则会发生干涉相涨，此时光探测器检测到的光功率最大，基于该原理调节移相器即可实现输入MMI的两路光信号的相位差为0或2π的整数倍，提高了本方案的实用价值。
在一些可能的实施方式中，第K个光功率调节模块还包括多个光分束器，控制装置包括M个控制模块。第K个光功率调节模块中每个MMI的2M-K+1个输出端口分别与2M-K+1个光分束器的输入端口连接，2M-K+1个光分束器的第一输出端口与第K+1个光功率调节模块中2K个MMI的输入端口连接，2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，第K个控制模块分别与第K个光功率调节模块中的每个移相器电连接。每个分束器用于对输入的光信号进行分路。分路后的其中一路光信号输出至第K+1个光功率调节模块中与每个分束器对应的MMI，分路后的另一路光信号输出至第K个控制模块。第K个控制模块用于对输入的光信号进行检测，并根据检测的结果调节第K个光功率调节模块中的每个移相器。在该实施方式中，提供了另一种控制模块对光信号进行检测的方式，控制模块具体用于对MMI输出的每一路光信号进行检测，再根据检测结果调节对应的移相器，实现了自动化地调节并增强了本方案的灵活性。
在一些可能的实施方式中，第K个控制模块包括2M-K+1个光探测器和2M-K相位控制单元。2M-K+1个光分束器的第二输出端口与2M-K+1个光探测器的输入端口连接，2M-K+1个光 探测器的输出端口都与相位控制单元的输入端口电连接，相位控制单元的输出端口与第K个光功率调节模块中的每个移相器电连接。第I个光探测器用于检测输入的光信号，第I个光探测器的输入端口与第I个光分束器的第二输出端口连接。第2M-K+1-I+1个光探测器用于检测输入的光信号，第2M-K+1-I+1个光探测器的输入端口与第2M-K+1-I+1个光分束器的第二输出端口连接。相位控制单元用于根据第I个光探测器和第2M-K+1-I+1个光探测器的检测结果调节第K个光功率调节模块中的第I个移相器，第I个移相器与第I个输入端口或第2M-K+1-I+1个输入端口连接。每个光探测器用于检测输入的光信号。相位控制单元用于根据每个光探测器的检测结果调节第K个光功率调节模块中的每个移相器。在该实施方式中，提供了一种控制模块的具体结构，如果MMI输出的两路光信号功率相同，此时两个光探测器检测到的光功率的差值最小，基于该原理调节移相器即可实现MMI输出的两路光信号的功率相同。不同于上述根据干涉相涨原理调节移相器的实施方式，扩展了本方案的实施方式。
在一些可能的实施方式中，多模光源为多模泵浦光源，光功率调节装置的输出的光信号用于注入掺铒光纤。本申请具体可应用于EDFA中，并且该光功率调节系统易于集成且成本较低。
在一些可能的实施方式中，模式解复用器可以是光纤形式的解复用器，例如光子灯笼等。或者，模式解复用器也可以是波导形式的解复用器，例如平板光波导(Planar optical waveguide，PLC)的解复用器和硅光模式解复用器等。又或者，模式解复用器还可以是空间形式的解复用器，例如基于相位掩模板的空间光模式解复用器等，提高了本方案的扩展性。
在一些可能的实施方式中，多模光源的输出端口通过多模光纤与模式解复用器的输入端口连接，模式解复用器的输出端口通过N根单模光纤或N路波导与光功率调节装置的输入端口连接，丰富了本方案的实现方式。
第二方面，本申请提供了一种光功率调节装置。该光功率调节装置包括M个光功率调节模块和控制装置，M为大于1的整数。每个光功率调节模块包括多个移相器，控制装置与M个光功率调节模块电连接。M个光功率调节模块从光功率调节装置的输入端口到光功率调节装置的输出端口依次排列，并且M个光功率调节模块串连在一起。光功率调节装置中的第K个光功率调节模块包括2K-1个多模干涉器MMI，每个MMI包括2M-K+1个输入端口和2M-K+1个输出端口，1≤K≤M。2M-K+1个输入端口中第I个输入端口或第2M-K+1-I+1个输入端口连接一个移相器，1≤I≤2M-K+1。控制装置用于调节第K个光功率调节模块中的移相器，以使得第K个光功率调节模块中每个MMI的第I个输入端口输入的光信号与第2M-K+1-I+1个输入端口输入的光信号的相位差为0或2π的整数倍。从而使得第K个光功率调节模块中每个MMI的第I个输出端口的输出光功率与第2M-K+1-I+1个输出端口的输出光功率相同。
在一些可能的实施方式中，光功率调节装置包括第一光功率调节模块和第二光功率调节模块。第一光功率调节模块包括第一MMI、第一移相器和第二移相器。第二光功率调节模块包括第二MMI、第三MMI、第三移相器和第四移相器。第一MMI的第二输入端口或第三输入端口与第一移相器连接，第二MMI的第一输入端口或第四输入端口与第二移相器连接，第二MMI的第一输入端口与第一MMI的第一输出端口连接，第二MMI的输入第二端口与第一MMI的第二输出端口连接，第三MMI的第一输入端口与第一MMI的第三输出端口连接，第三MMI的第二输入端口与第一MMI的第四输出端口连接，第三移相器连接在第二MMI的第一输入端口与 第一MMI的第一输出端口之间或第二MMI的第二输入端口与第一MMI的第二输出端口之间，第四移相器连接在第三MMI的第一输入端口与第一MMI的第三输出端口之间或第三MMI的第二输入端口与第一MMI的第四输出端口之间。
控制装置用于调节第一移相器，以使得第一MMI的第二输入端口输入的光信号与第一MMI的第三输入端口输入的光信号的相位差为0或2π的整数倍，并使得第一MMI的第二输出端口的输出光功率与第一MMI的第三输出端口的输出光功率相同。控制装置用于调节第二移相器，以使得第一MMI的第一输入端口输入的光信号与第一MMI的第四输入端口输入的光信号的相位差为0或2π的整数倍，并使得第一MMI的第一输出端口的输出光功率与第一MMI的第四输出端口的输出光功率相同。控制装置用于调节第三移相器，以使得第二MMI的第一输入端口输入的光信号与第二MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得第二MMI的第一输出端口的输出光功率与第二MMI的第二输出端口的输出光功率相同。控制装置用于调节第四移相器，以使得第三MMI的第一输入端口输入的光信号与第三MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得第三MMI的第一输出端口的输出光功率与第三MMI的第二输出端口的输出光功率相同。在该实施方式中，提供了一种组成光功率调节装置的最小结构，增强了本方案的可实现性。
在一些可能的实施方式中，每个光功率调节模块中的所有MMI的多模干涉区长度都为3L π/2，L π为MMI波导中两个最低阶模式的拍长。在该实施方式中，无论N×N的MMI的输入输出端口数量是多少，其多模干涉区长度都为3L π/2。而N×N的光耦合器的多模干涉区长度都为3L π/N。可见，本申请提供的N×N的MMI与N×N的光耦合器不同，NxN光耦合器只能用于输入的N路光是非相干光的场景，而本申请提供的N×N的MMI可应用于将多模光信号转化为N路相干的单模光信号的场景，增强了本方案的实用性。
在一些可能的实施方式中，不同光功率调节模块中MMI的多模干涉区长度不同，提高了本方案的灵活性。
在一些可能的实施方式中，第K个光功率调节模块还包括多个光分束器，控制装置包括M个控制模块。第K个光功率调节模块中每个MMI的2M-K+1个输入端口分别与2M-K+1个光分束器的第一输出端口连接，2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，第K个控制模块分别与第K个光功率调节模块中的每个移相器电连接。每个光分束器用于对输入的光信号进行分路，分路后的其中一路光信号输出至与每个光分束器对应的MMI，分路后的另一路光信号输出至第K个控制模块。第K个控制模块用于对输入的光信号进行检测，并根据检测的结果调节第K个光功率调节模块中的每个移相器。在该实施方式中，提供了一种控制模块对光信号进行检测的方式，控制模块具体用于对输入MMI的每一路光信号进行检测，再根据检测结果调节对应的移相器，实现了自动化地调节。
在一些可能的实施方式中，第K个控制模块包括2M-K个耦合器、2M-K个光探测器和2M-K相位控制单元。第I个输入端口与第I个光分束器的第一输出端口连接。第2M-K+1-I+1个输入端口与第2M-K+1-I+1个光分束器的第一输出端口连接。第I个光分束器的第二输出端口和第2M-K+1-I+1个光分束器的第二输出端口与第J个耦合器的输入端口连接，1≤J≤2M-K。第J个耦合器输出端口与第J个光探测的输入端口连接。第J个光探测器的输出端口与相位控制单元的输入端口电连接。相位控制单元的输出端口与第K个光功率调节模块中的每个移相 器电连接。第J个耦合器用于对输入的光信号进行耦合。第J个光探测器用于对耦合后的光信号进行检测。相位控制单元用于根据第J个光探测器的检测结果调节第K个光功率调节模块中的第I个移相器，第I个移相器与第I个输入端口或第2M-K+1-I+1个输入端口连接。在该实施方式中，提供了一种控制模块的具体结构，如果输入MMI的两路光信号同相位，则会发生干涉相涨，此时光探测器检测到的光功率最大，基于该原理调节移相器即可实现输入MMI的两路光信号的相位差为0或2π的整数倍，提高了本方案的实用价值。
在一些可能的实施方式中，第K个光功率调节模块还包括多个光分束器，控制装置包括M个控制模块。第K个光功率调节模块中每个MMI的2M-K+1个输出端口分别与2M-K+1个光分束器的输入端口连接，2M-K+1个光分束器的第一输出端口与第K+1个光功率调节模块中2K个MMI的输入端口连接，2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，第K个控制模块分别与第K个光功率调节模块中的每个移相器电连接。每个分束器用于对输入的光信号进行分路。分路后的其中一路光信号输出至第K+1个光功率调节模块中与每个分束器对应的MMI，分路后的另一路光信号输出至第K个控制模块。第K个控制模块用于对输入的光信号进行检测，并根据检测的结果调节第K个光功率调节模块中的每个移相器。在该实施方式中，提供了另一种控制模块对光信号进行检测的方式，控制模块具体用于对MMI输出的每一路光信号进行检测，再根据检测结果调节对应的移相器，实现了自动化地调节并增强了本方案的灵活性。
在一些可能的实施方式中，第K个控制模块包括2M-K+1个光探测器和2M-K相位控制单元。2M-K+1个光分束器的第二输出端口与2M-K+1个光探测器的输入端口连接，2M-K+1个光探测器的输出端口都与相位控制单元的输入端口电连接，相位控制单元的输出端口与第K个光功率调节模块中的每个移相器电连接。第I个光探测器用于检测输入的光信号，第I个光探测器的输入端口与第I个光分束器的第二输出端口连接。第2M-K+1-I+1个光探测器用于检测输入的光信号，第2M-K+1-I+1个光探测器的输入端口与第2M-K+1-I+1个光分束器的第二输出端口连接。相位控制单元用于根据第I个光探测器和第2M-K+1-I+1个光探测器的检测结果调节第K个光功率调节模块中的第I个移相器，第I个移相器与第I个输入端口或第2M-K+1-I+1个输入端口连接。每个光探测器用于检测输入的光信号。相位控制单元用于根据每个光探测器的检测结果调节第K个光功率调节模块中的每个移相器。在该实施方式中，提供了一种控制模块的具体结构，如果MMI输出的两路光信号功率相同，此时两个光探测器检测到的光功率的差值最小，基于该原理调节移相器即可实现MMI输出的两路光信号的功率相同。不同于上述根据干涉相涨原理调节移相器的实施方式，扩展了本方案的实施方式。
本申请实施例中，提供了一种光功率调节系统。模式解复用器可以将多模光源输出的N路横模光信号转换为N路基模光信号。之后，N路基模光信号输入到光功率调节装置。光功率调节装置包括多级光功率调节模块和控制装置。其中，每级光功率调节模块的输入输出端口可以按两两一组的方式拆分成多组输入输出端口。每一组输入输出端口对应一个移相器。控制装置可以通过调节每个移相器，使得每一级光功率调节模块的每一组输出端口的输出光功率相同。按照一定的设计方式，每一级光功率调节模块完成调节后，都将增加部分光功率相同的光信号。以此类推，当所有的光功率调节模块都完成调节后，就可以保证光功率调节装置输出的N路光信号的光功率相同。应理解，无论模式解复用后的基模光信号数量有多少， 都可以通过上述的功率调节方式，使得每一路基模光信号的功率相同，功率调节的精度更高，并且适用性更广。
附图说明
图1为本申请实施例提供的光功率调节系统的一种结构示意图；
图2为本申请实施例提供的光功率调节装置的一种结构示意图；
图3为本申请实施例提供的光功率调节装置的另一种结构示意图；
图4(a)为本申请实施例提供的光功率调节装置的另一种结构示意图；
图4(b)为本申请实施例提供的控制模块的一种结构示意图；
图5(a)为本申请实施例提供的光功率调节装置的另一种结构示意图；
图5(b)为本申请实施例提供的控制模块的另一种结构示意图；
图6为本申请实施例提供的光功率调节装置的另一种结构示意图。
具体实施方式
本申请实施例提供了一种光功率调节系统和光功率调节装置，模式解复用器可以将多模光源输出的N路横模光信号转换为N路基模光信号，通过光功率调节装置可以使得每一路基模光信号的功率相同，功率调节的精度更高，并且适用性更广。
需要说明的是，本申请说明书和权利要求书及上述附图中的术语“第一”、“第二”、“第三”和“第四”等用于区别类似的对象，而非限定特定的顺序或先后次序。应理解，上述术语在适当情况下可以互换，以便在本申请描述的实施例能够以除了在本申请描述的内容以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含。例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
本申请提供的光功率调节系统主要应用于将多模光信号解复用为多个单模光信号后，再对多个单模光信号进行功率均衡的场景中。作为一个示例，该光功率调节系统具体可应用于掺铒光纤放大器(Erbium-Doped Fiber Amplifier，EDFA)中。泵浦光源是EDFA中必不可少的组成部分，泵浦光功率的大小影响着掺铒光纤放大器的增益。通常单模泵浦光源的价格较贵，而多模泵浦光源的价格便宜。但是多模泵浦光源输出的光由于存在多个横模，无法直接应用于EDFA，一般需要通过模式解复用为多个单模的光后再输出。并且，还需要对多个单模光信号进行功率均衡，以将多个功率近似或相同的单模光信号提供给多个EDFA。
为此，本申请提供了一种光功率调节系统用于通过调节使得每一路基模光信号的功率相同。下面对本申请提供的光功率调节系统进行介绍。需要说明的是，以下各附图中的实线表示光信号的传输路径，虚线表示电信号的传输路径。
图1为本申请实施例提供的光功率调节系统的一种结构示意图。如图1所示，光功率调节系统包括：多模光源10、模式解复用器20和光功率调节装置30。其中，多模光源10的输 出端口与模式解复用器20的输入端口连接，模式解复用器20的输出端口与光功率调节装置30的输入端口连接。光功率调节装置包括M个光功率调节模块和控制装置，M个光功率调节模块从光功率调节装置的输入端口到光功率调节装置的输出端口依次排列，并且M个光功率调节模块串连在一起，M为大于1的整数。控制装置与M个光功率调节模块电连接。具体地，多模光源10用于输出多模光信号，多模光信号包括N路横模光信号，N＝2M。应理解，多模光源10输出的光场既有多横模也有多纵模，对于EDFA的泵浦，多纵模的影响并不大。但是，EDFA用的是单模掺铒光纤，无法支持高阶横模，多横模会造成泵浦光功率的浪费。因此，需要通过模式解复用器20将N路横模光信号转换为N路基模光信号，并输出N路基模光信号至光功率调节装置30。进而，通过光功率调节装置30的功率调节后，光功率调节装置30输出的N路光信号的功率相同。应理解，在实际应用中，光功率调节装置30输出的N路光信号的功率只要在允许接受的误差范围内都可以认定为功率相同。
需要说明的是，上述多模光源10具体可以是多模泵浦光源，多模光源10通过多模光纤与模式解复用器20连接。光功率调节装置30输出的N路光信号分别用于注入对应的掺铒光纤。模式解复用器20可以是光纤形式的解复用器，例如光子灯笼等。或者，模式解复用器20也可以是波导形式的解复用器，例如平板光波导(Planar optical waveguide，PLC)的解复用器和硅光模式解复用器等。又或者，模式解复用器20还可以是空间形式的解复用器，例如基于相位掩模板的空间光模式解复用器等。应理解，如果模式解复用器20是光纤形式的解复用器，那么模式解复用器20通过N根单模光纤与光功率调节装置30连接，光功率调节装置30中的M个光功率调节模块也通过光纤串连在一起。如果模式解复用器20是波导形式的解复用器，那么模式解复用器20通过N根波导与光功率调节装置30连接，光功率调节装置30中的M个光功率调节模块也通过波导串连在一起。
下面结合光功率调节装置30的结构对功率调节的具体方式进行介绍。图2为本申请实施例提供的光功率调节装置的一种结构示意图。如图2所示，每个光功率调节模块包括至少一个多模干涉器(MultiMode Inferometer，MMI)多个移相器。其中，每个光功率调节模块中MMI的数量和移相器的数量由光功率调节模块的次序决定。第一个光功率调节模块的输入端口就是光功率调节装置30的输入端口，第M个光功率调节模块的输出端口就是光功率调节装置30的输出端口。具体地，第K个光功率调节模块包括2K-1个多模干涉器MMI，每个MMI包括2M-K+1个输入端口和2M-K+1个输出端口，1≤K≤M。2M-K+1个输入端口中第I个输入端口或第2M-K+1-I+1个输入端口连接一个移相器，1≤I≤2M-K+1。控制装置通过调节第K个光功率调节模块中每个移相器，以使得第K个光功率调节模块中每个MMI的第I个输入端口输入的光信号与第2M-K+1-I+1个输入端口输入的光信号的相位差为0或2π的整数倍。进而，就可以使得第K个光功率调节模块中每个MMI的第I个输出端口的输出光功率与第2M-K+1-I+1个输出端口的输出光功率相同。每一个光功率调节模块都按照上述的方式进行功率调节，就能保证第M个光功率调节模块输出的N路光信号的光功率相同。
需要说明的是，每个光功率调节模块中的所有MMI的多模干涉区长度都为3L π/2，L π为MMI波导中两个最低阶模式的拍长。并且，不同光功率调节模块中MMI的多模干涉区长度不同。
下面以光功率调节装置所能支持的最小结构为例对功率调节的具体方式进行进一步介绍。 图3为本申请实施例提供的光功率调节装置的另一种结构示意图。如图3所示，光功率调节装置30包括光功率调节模块301、光功率调节模块302和控制装置303。光功率调节模块301包括一个4×4的MMI 301a、移相器301b和移相器301c。光功率调节模块302包括2×2的MMI 302a、2×2的MMI302b、移相器301c和移相器301d。应理解，图3中所示的各移相器的位置只是一个示例。具体地，MMI 301a的输入端口1或输入端口4用于连接移相器301c，MMI 301a的输入端口2或输入端口3用于连接移相器301b。MMI 302a的输入端口1或输入端口2用于连接移相器302c。MMI 302b的输入端口1或输入端口2用于连接移相器302d。控制装置303通过调节移相器301b，使得MMI 301a的输入端口2和输入端口3输入的光信号的相位差为0或2π的整数倍，进而使得MMI 301a的输出端口2和输出端口3的输出光功率相同。控制装置303通过调节移相器301c，使得MMI 301a的输入端口1和输入端口4输入的光信号的相位差为0或2π的整数倍，进而使得MMI 301a的输出端口1和输出端口4的输出光功率相同。控制装置303通过调节移相器302c，使得MMI 302a的输入端口1和输入端口2输入的光信号的相位差为0或2π的整数倍，进而使得MMI 302a的输出端口1和输出端口2的输出光功率相同。控制装置303通过调节移相器302d，使得MMI 302b的输入端口1和输入端口2输入的光信号的相位差为0或2π的整数倍，进而使得MMI 302b的输出端口1和输出端口2的输出光功率相同。
通过上述描述，光功率调节模块301输入的4路光信号可以分为两组，通过调节后输出端口1与输出端口4输出的一组光功率相同，输出端口2与输出端口3输出的一组光功率相同。然后，再通过光功率调节模块302将这两组光信号的光功率调节一致，最终光功率调节模块302输出的4路光信号的光功率相同。下面对采用上述设计方式的原理进行介绍。
设MMI 301a的输入端口1至输入端口4输入的4路信号分别为：E 1＝a,
Figure PCTCN2022086738-appb-000001
Figure PCTCN2022086738-appb-000002
其中，a,b,c,d分别为四路输入的光功率，j为一个虚数，
Figure PCTCN2022086738-appb-000003
分别为输入端口2、输入端口3、输入端口4的光信号与输入端口1的光信号的相位差。输入端口x到输出端口y的相位传递函数表示为：
Figure PCTCN2022086738-appb-000004
Figure PCTCN2022086738-appb-000005
其中，
Figure PCTCN2022086738-appb-000006
为常数相位，当N＝4时，输入输出端口的传输矩阵表示为：
Figure PCTCN2022086738-appb-000007
对于4×4的MMI 301a来说，输入输出端口的传输矩阵表示为：
Figure PCTCN2022086738-appb-000008
MMI 301a的四个输出端口的光场分别表示为：
Figure PCTCN2022086738-appb-000009
Figure PCTCN2022086738-appb-000010
Figure PCTCN2022086738-appb-000011
Figure PCTCN2022086738-appb-000012
当
Figure PCTCN2022086738-appb-000013
即输入端口1的光信号与输入端口4的光信号相位差为0或2π的整数倍，输入端口2的光信号与输入端口3的光信号相位差为0或2π的整数倍，则MMI 301a的四个输出端口的输出光功率分别表示为：
Figure PCTCN2022086738-appb-000014
Figure PCTCN2022086738-appb-000015
Figure PCTCN2022086738-appb-000016
Figure PCTCN2022086738-appb-000017
由上式可知，当MMI 301a输入端口1和4的光信号相位相等时，输出端口1和输出端口4将实现对输入端口1和输入端口4的功率均衡。同理，当输入端口2和输入端口3的光信号相位相等时，输出端口2和输出端口3将实现对输入端口2和输入端口3的功率均衡。
接下来，将MMI 301a的输出端口1和输出端口2分别接入MMI 302a的输入端口1和输入端口2，通过调节移相器302c使得输入到MMI 302a的输入端口的两路光信号相位相同，MMI 302a的传输矩阵为：
Figure PCTCN2022086738-appb-000018
通过计算可得MMI 302a的输出端口1和输出端口2的输出光功率均为
Figure PCTCN2022086738-appb-000019
同理，MMI 302b的输出端口1和输出端口2的输出光功率也均为
Figure PCTCN2022086738-appb-000020
从而实现了4路光信号的功率均衡。
需要说明的是，本申请所采用的N×N的MMI与N×N光耦合器有以下几点区别。第一、NxN光耦合器只能用于输入的N路光是非相干光的情况，而对于将多模光信号转化为N路单 模光信号的场景，这N路单模光信号是相干光，所以无法直接使用NxN光耦合器来实现光功率均衡。第二、对于NxN光耦合器，需要将输入的N路光信号的相位都调节一致才能使N路输出的光功率都相同。但是，由于N的数量通常较大，无法探测N路输入的光信号的绝对相位，所以通过NxN光耦合器无法保证N路输入光信号的相位完全一致。对于本申请提供的N×N的MMI，两路光信号的相对相位差是可以探测的，通过移相器就可以将这一组中的两路输入光信号的相位调节一致。基于这个设计思路，通过多个级联的光功率调节模块就可以实现N路输出的光功率均衡。
应理解，本申请提供的控制装置可以实现对两路输入光信号的相位差提取，并控制移相器调节输入光信号的相位。也就是说，本申请提供的光功率调节装置是自动化实现功率调节的，而无需人为控制。具体地，本申请提供了多种通过控制装置探测相位差的实现方式，下面以上述图3所示的光功率调节装置为例分别进行介绍。
第一种实施方式：
图4(a)为本申请实施例提供的光功率调节装置的另一种结构示意图。如图4(a)所示，光功率调节模块301和光功率调节模块302中还分别包括多个光分束器。控制装置303包括控制模块1和控制模块2，其中，控制模块1用于控制光功率调节模块301中的移相器，控制模块2用于控制光功率调节模块302中的移相器。以光功率调节模块301中的光分束器为例，每个光分束器用于对输入MMI 301a的每一路光信号进行分路，分路后的其中一路光信号输出至MMI 301a，分路后的另一路光信号输出至控制模块1。同理也适用于光功率调节模块302中的光分束器，此处不再赘述。需要说明的是，本申请不限定每个光分束器的分光比，作为一种优选的实现方式，分路后的大部分光信号应输出至对应的MMI，分路后的少部分光信号输出至对应的控制模块。
图4(b)为本申请实施例提供的控制模块的一种结构示意图。如图4(b)所示，控制模块1包括耦合器303a、光探测器303b和相位控制单元303c。MMI 301a的输入端口1所连接的光分束器还与耦合器303a连接，MMI 301a的输入端口4所连接的光分束器还与耦合器303a连接。耦合器303a用于对输入的光信号进行耦合。光探测器303b用于对耦合后的光信号进行检测。相位控制单元303c用于根据光探测器303b输出的检测结果调节移相器301c。具体地，相位控制单元303c可以逐步调节其输出的电压，以使得移相器301c的相位值在0-2π的范围内扫描。在这个过程中，光探测器303b持续对耦合器303a输出的光信号进行功率探测。相位控制单元303c可以持续读取光探测器303b输出的电压。应理解，如果输入耦合器303a的两路光信号的相位差为0或2π的整数倍，则两路光信号会干涉相涨，此时耦合器303a的输出光功率最大，光探测器303b的输出电压也最大，相位控制单元303c就可以维持当前的输出电压，以使得输入耦合器303a的两路光信号的相位差为0或2π的整数倍。从而使得MMI 301a的输出端口1和输出端口4的输出光功率相同。需要说明的是，上述图4(b)只画出了控制模块1中对应移相器301c的一部分，对应移相器301b的结构也与图4(b)画出的部分类似，此处不再赘述。
第二种实施方式：
图5(a)为本申请实施例提供的光功率调节装置的另一种结构示意图。如图5(a)所示，光功率调节模块301和光功率调节模块302中还分别包括多个光分束器。控制装置303包括 控制模块1和控制模块2，其中，控制模块1用于控制光功率调节模块301中的移相器，控制模块2用于控制光功率调节模块302中的移相器。以光功率调节模块301中的光分束器为例，每个分束器用于对MMI 301a输出的每一路光信号进行分路，分路后的其中一路光信号输出至光功率调节模块302，分路后的另一路光信号输出至控制模块1。同理也适用于光功率调节模块302中的光分束器，此处不再赘述。需要说明的是，本申请不限定每个光分束器的分光比，作为一种优选的实现方式，分路后的大部分光信号应输出至对应的MMI，分路后的少部分光信号输出至对应的控制模块。
图5(b)为本申请实施例提供的控制模块的另一种结构示意图。如图5(b)所示，控制模块1包括光探测器303d、光探测器303e和相位控制单元303c。MMI 301a的输出端口1所连接的光分束器还与光探测器303d连接，MMI 301a的输出端口4所连接的光分束器还与光探测器303e连接。光探测器303d和光探测器303e分别用于对各自输入的光信号进行检测。相位控制单元303c用于根据光探测器303d和光探测器303e输出的检测结果调节移相器301c。具体地，相位控制单元303c可以逐步调节其输出的电压，以使得移相器301c的相位值在0-2π的范围内扫描。在这个过程中，相位控制单元303c可以持续读取光探测器303d和光探测器303e输出的电压，并计算两个输入电压的差值。应理解，当相位控制单元303c计算得到的电压差值最小时，就说明书光探测器303d和光探测器303e检测到的光功率相同。此时，相位控制单元303c就可以维持当前的输出电压，以使得MMI 301a的输出端口1和输出端口4的输出光功率相同。需要说明的是，上述图5(b)只画出了控制模块1中对应移相器301c的一部分，对应移相器301b的结构也与图5(b)画出的部分类似，此处不再赘述。
本申请实施例中，提供了一种光功率调节系统。模式解复用器可以将多模光源输出的N路横模光信号转换为N路基模光信号。之后，N路基模光信号输入到光功率调节装置。光功率调节装置包括多级光功率调节模块和控制装置。其中，每级光功率调节模块的输入输出端口可以按两两一组的方式拆分成多组输入输出端口。每一组输入输出端口对应一个移相器。控制装置可以通过调节每个移相器，使得每一级光功率调节模块的每一组输出端口的输出光功率相同。按照一定的设计方式，每一级光功率调节模块完成调节后，都将增加部分光功率相同的光信号。以此类推，当所有的光功率调节模块都完成调节后，就可以保证光功率调节装置输出的N路光信号的光功率相同。应理解，无论模式解复用后的基模光信号数量有多少，都可以通过上述的功率调节方式，使得每一路基模光信号的功率相同，功率调节的精度更高，并且适用性更广。
图6为本申请实施例提供的光功率调节装置的另一种结构示意图。如图6所示，区别于上述各实施例介绍的光功率调节装置，该光功率调节装置的每个光功率调节模块中采用相同的N×N的MMI。以N＝4为例，光功率调节模块301和光功率调节模块302都只包括一个4×4的MMI。并且，光功率调节模块301的输出端口与光功率调节模块302的输入端口并不是完全按照端口编号对应连接，而是采用了部分交叉连接的方式。其中，光功率调节模块301与上述图3所示实施例中的光功率调节模块301类似，此处不再赘述。下面主要对光功率调节模块302的结构进行说明。
以图6为例，MMI 301a的输出端口1与MMI 302a的输入端口1连接，MMI 301a的输出端口2与MMI 302a的输入端口2连接，MMI 301a的输出端口3与MMI 302a的输入端口4连 接，MMI 301a的输出端口4与MMI 302a的输入端口3连接。应理解，对于MMI 302a来说，输入端口1和输入端口4为同一组输入端口，输入端口2和输入端口3为同一组输入端口。由于MMI 301a的输出端口3和输出端口4与MMI 302a的输入端口3和输入端口4是交叉连接的，因此，MMI 302a的输入端口1和输入端口3的输入光功率相同，输入端口2和输入端口4的输入光功率相同。那么，MMI 302a的输入端口1或输入端口4应连接移相器302b，通过调节后使得MMI 302a的输出端口1或输出端口4的输出光功率相同。MMI 302a的输入端口2或输入端口3应连接移相器302c，通过调节后使得MMI 302a的输出端口2或输出端口3的输出光功率相同。最终，MMI 302a四个输出端口的输出光功率相同。具体的功率调节方式与上述实施例中介绍的方式类似，此处不再赘述。
需要说明的是，上述图6所示的连接方式可以理解为是端口1和端口2直连，端口3和端口4交叉的连接方式。除此之外，基于相同的设计思路，也可以是端口1和端口3直连，端口2和端口4交叉的连接方式，或者，端口3和端口4直连，端口1和端口2交叉的连接方式，或者，端口2和端口4直连，端口1和端口3交叉的连接方式。应理解，基于上述图6所示实施例的设计思路，本申请也可以将这种实施方式扩展到光功率调节模块的数量大于2个的场景中，具体此处不再赘述。
需要说明的是，本申请实施例还提供了一种光功率调节装置，该光功率调节装置可以是上述图1-图6任意实施例中所述的光功率调节装置，具体请参阅上述图1-图6所示实施例的相关描述，此处不再赘述。

Claims (19)

  1. 一种光功率调节系统，其特征在于，包括：多模光源、模式解复用器和光功率调节装置，其中，所述多模光源的输出端口与所述模式解复用器的输入端口连接，所述模式解复用器的输出端口与所述光功率调节装置的输入端口连接；
    所述多模光源用于输出多模光信号，所述多模光信号包括N路横模光信号，所述N＝2M，所述M为大于1的整数；
    所述模式解复用器用于将所述N路横模光信号转换为N路基模光信号，并输出所述N路基模光信号；
    所述光功率调节装置包括M个光功率调节模块和控制装置，每个所述光功率调节模块包括多个移相器，所述控制装置与所述M个光功率调节模块电连接，所述M个光功率调节模块从所述光功率调节装置的输入端口到所述光功率调节装置的输出端口依次排列，并且所述M个光功率调节模块串连在一起，所述光功率调节装置中的第K个光功率调节模块包括2K-1个多模干涉器MMI，每个所述MMI包括2M-K+1个输入端口和2M-K+1个输出端口，1≤所述K≤所述M，所述2M-K+1个输入端口中第I个输入端口或第2M-K+1-I+1个输入端口连接一个移相器，1≤所述I≤2M-K+1；
    所述控制装置用于调节所述第K个光功率调节模块中的移相器，以使得第K个光功率调节模块中每个所述MMI的第I个输入端口输入的光信号与第2M-K+1-I+1个输入端口输入的光信号的相位差为0或2π的整数倍，并使得第K个光功率调节模块中每个所述MMI的第I个输出端口的输出光功率与第2M-K+1-I+1个输出端口的输出光功率相同。
  2. 根据权利要求1所述的光功率调节系统，其特征在于，所述光功率调节装置包括第一光功率调节模块和第二光功率调节模块，所述第一光功率调节模块包括第一MMI、第一移相器和第二移相器，所述第二光功率调节模块包括第二MMI、第三MMI、第三移相器和第四移相器；
    所述第一MMI的第二输入端口或第三输入端口与所述第一移相器连接，所述第二MMI的第一输入端口或第四输入端口与所述第二移相器连接，所述第二MMI的第一输入端口与所述第一MMI的第一输出端口连接，所述第二MMI的输入第二端口与所述第一MMI的第二输出端口连接，所述第三MMI的第一输入端口与所述第一MMI的第三输出端口连接，所述第三MMI的第二输入端口与所述第一MMI的第四输出端口连接，所述第三移相器连接在所述第二MMI的第一输入端口与所述第一MMI的第一输出端口之间或所述第二MMI的第二输入端口与所述第一MMI的第二输出端口之间，所述第四移相器连接在所述第三MMI的第一输入端口与所述第一MMI的第三输出端口之间或所述第三MMI的第二输入端口与所述第一MMI的第四输出端口之间；
    所述控制装置用于调节所述第一移相器，以使得所述第一MMI的第二输入端口输入的光信号与所述第一MMI的第三输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第一MMI的第二输出端口的输出光功率与所述第一MMI的第三输出端口的输出光功率相同；
    所述控制装置用于调节所述第二移相器，以使得所述第一MMI的第一输入端口输入的光信号与所述第一MMI的第四输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第一MMI的第一输出端口的输出光功率与所述第一MMI的第四输出端口的输出光功率相同；
    所述控制装置用于调节第三移相器，以使得所述第二MMI的第一输入端口输入的光信号与所述第二MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第二MMI的第一输出端口的输出光功率与所述第二MMI的第二输出端口的输出光功率相同；
    所述控制装置用于调节第四移相器，以使得所述第三MMI的第一输入端口输入的光信号与所述第三MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第三MMI的第一输出端口的输出光功率与所述第三MMI的第二输出端口的输出光功率相同。
  3. 根据权利要求1或2所述的光功率调节系统，其特征在于，每个光功率调节模块中的所有MMI的多模干涉区长度都为3L π/2，所述L π为MMI波导中两个最低阶模式的拍长。
  4. 根据权利要求3所述的光功率调节系统，其特征在于，不同光功率调节模块中MMI的多模干涉区长度不同。
  5. 根据权利要求1至4中任一项所述的光功率调节系统，其特征在于，所述第K个光功率调节模块还包括多个光分束器，所述控制装置包括M个控制模块，所述第K个光功率调节模块中每个MMI的2M-K+1个输入端口分别与2M-K+1个光分束器的第一输出端口连接，所述2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，所述第K个控制模块分别与所述第K个光功率调节模块中的每个移相器电连接；
    每个所述光分束器用于对输入的光信号进行分路，分路后的其中一路光信号输出至与每个所述光分束器对应的MMI，分路后的另一路光信号输出至所述第K个控制模块；
    所述第K个控制模块用于对输入的光信号进行检测，并根据所述检测的结果调节所述第K个光功率调节模块中的每个移相器。
  6. 根据权利要求5所述的光功率调节系统，其特征在于，所述第K个控制模块包括2M-K个耦合器、2M-K个光探测器和2M-K相位控制单元，所述第I个输入端口与第I个光分束器的第一输出端口连接，所述第2M-K+1-I+1个输入端口与所述第2M-K+1-I+1个光分束器的第一输出端口连接，所述第I个光分束器的第二输出端口和所述第2M-K+1-I+1个光分束器的第二输出端口与所述第J个耦合器的输入端口连接，1≤所述J≤2M-K，所述第J个耦合器输出端口与所述第J个光探测的输入端口连接，所述第J个光探测器的输出端口与所述相位控制单元的输入端口电连接，所述相位控制单元的输出端口与所述第K个光功率调节模块中的每个移相器电连接；
    所述第J个耦合器用于对输入的光信号进行耦合；
    所述第J个光探测器用于对所述耦合后的光信号进行检测；
    所述相位控制单元用于根据所述第J个光探测器的检测结果调节所述第K个光功率调节模块中的第I个移相器，所述第I个移相器与所述第I个输入端口或所述第2M-K+1-I+1个输入端口连接。
  7. 根据权利要求1至4中任一项所述的光功率调节系统，其特征在于，所述第K个光功率调节模块还包括多个光分束器，所述控制装置包括M个控制模块，所述第K个光功率调节模块中每个MMI的2M-K+1个输出端口分别与2M-K+1个光分束器的输入端口连接，所述2M-K+1个光分束器的第一输出端口与第K+1个光功率调节模块中2K个MMI的输入端口连接，所述2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，所述第K个控制模块分别与所述第K个光功率调节模块中的每个移相器电连接；
    每个所述分束器用于对输入的光信号进行分路，分路后的其中一路光信号输出至第K+1个光功率调节模块中与每个所述分束器对应的MMI，分路后的另一路光信号输出至所述第K个控制模块；
    所述第K个控制模块用于对输入的光信号进行检测，并根据所述检测的结果调节所述第K个光功率调节模块中的每个移相器。
  8. 根据权利要求7所述的光功率调节系统，其特征在于，所述第K个控制模块包括2M-K+1个光探测器和2M-K相位控制单元，所述2M-K+1个光分束器的第二输出端口与所述2M-K+1个光探测器的输入端口连接，所述2M-K+1个光探测器的输出端口都与所述相位控制单元的输入端口电连接，所述相位控制单元的输出端口与所述第K个光功率调节模块中的每个移相器电连接；
    第I个光探测器用于检测输入的光信号，所述第I个光探测器的输入端口与第I个光分束器的第二输出端口连接；
    第2M-K+1-I+1个光探测器用于检测输入的光信号，所述第2M-K+1-I+1个光探测器的输入端口与第2M-K+1-I+1个光分束器的第二输出端口连接；
    所述相位控制单元用于根据所述第I个光探测器和所述第2M-K+1-I+1个光探测器的检测结果调节所述第K个光功率调节模块中的第I个移相器，所述第I个移相器与所述第I个输入端口或所述第2M-K+1-I+1个输入端口连接；
    每个所述光探测器用于检测输入的光信号；
    所述相位控制单元用于根据每个所述光探测器的检测结果调节所述第K个光功率调节模块中的每个移相器。
  9. 根据权利要求1至8中任一项所述的光功率调节系统，其特征在于，所述多模光源为多模泵浦光源，所述光功率调节装置的输出的光信号用于注入掺铒光纤。
  10. 根据权利要求1至9中任一项所述的光功率调节系统，其特征在于，所述模式解复器为光子灯笼、波导形式的解复用器或空间光形式的解复用器。
  11. 根据权利要求1至10中任一项所述的光功率调节系统，其特征在于，所述多模光源的输出端口通过多模光纤与所述模式解复用器的输入端口连接，所述模式解复用器的输出端口通过N根单模光纤或N路波导与所述光功率调节装置的输入端口连接。
  12. 一种光功率调节装置，其特征在于，包括：M个光功率调节模块和控制装置，所述M为大于1的整数，每个所述光功率调节模块包括多个移相器，所述控制装置与所述M个光功率调节模块电连接，所述M个光功率调节模块从所述光功率调节装置的输入端口到所述光功率调节装置的输出端口依次排列，并且所述M个光功率调节模块串连在一起，所述光功率调节装置中的第K个光功率调节模块包括2K-1个多模干涉器MMI，每个所述MMI包括2M-K+1个输入端口和2M-K+1个输出端口，1≤所述K≤所述M，所述2M-K+1个输入端口中第I个输入端口或第2M-K+1-I+1个输入端口连接一个移相器，1≤所述I≤2M-K+1；
    所述控制装置用于调节所述第K个光功率调节模块中的移相器，以使得第K个光功率调节模块中每个所述MMI的第I个输入端口输入的光信号与第2M-K+1-I+1个输入端口输入的光信号的相位差为0或2π的整数倍，并使得第K个光功率调节模块中每个所述MMI的第I个输出端口的输出光功率与第2M-K+1-I+1个输出端口的输出光功率相同。
  13. 根据权利要求12所述的光功率调节装置，其特征在于，所述光功率调节装置包括第一光功率调节模块和第二光功率调节模块，所述第一光功率调节模块包括第一MMI、第一移相器和第二移相器，所述第二光功率调节模块包括第二MMI、第三MMI、第三移相器和第四移相器；
    所述第一MMI的第二输入端口或第三输入端口与所述第一移相器连接，所述第二MMI的第一输入端口或第四输入端口与所述第二移相器连接，所述第二MMI的第一输入端口与所述第一MMI的第一输出端口连接，所述第二MMI的输入第二端口与所述第一MMI的第二输出端口连接，所述第三MMI的第一输入端口与所述第一MMI的第三输出端口连接，所述第三MMI的第二输入端口与所述第一MMI的第四输出端口连接，所述第三移相器连接在所述第二MMI的第一输入端口与所述第一MMI的第一输出端口之间或所述第二MMI的第二输入端口与所述第一MMI的第二输出端口之间，所述第四移相器连接在所述第三MMI的第一输入端口与所述第一MMI的第三输出端口之间或所述第三MMI的第二输入端口与所述第一MMI的第四输出端口之间；
    所述控制装置用于调节所述第一移相器，以使得所述第一MMI的第二输入端口输入的光信号与所述第一MMI的第三输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第一MMI的第二输出端口的输出光功率与所述第一MMI的第三输出端口的输出光功率相同；
    所述控制装置用于调节所述第二移相器，以使得所述第一MMI的第一输入端口输入的光信号与所述第一MMI的第四输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第一MMI的第一输出端口的输出光功率与所述第一MMI的第四输出端口的输出光功率相同；
    所述控制装置用于调节第三移相器，以使得所述第二MMI的第一输入端口输入的光信号与所述第二MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第二MMI的第一输出端口的输出光功率与所述第二MMI的第二输出端口的输出光功率相同；
    所述控制装置用于调节第四移相器，以使得所述第三MMI的第一输入端口输入的光信号与所述第三MMI的第二输入端口输入的光信号的相位差为0或2π的整数倍，并使得所述第三MMI的第一输出端口的输出光功率与所述第三MMI的第二输出端口的输出光功率相同。
  14. 根据权利要求12或13所述的光功率调节装置，其特征在于，每个光功率调节模块中的所有MMI的多模干涉区长度都为3L π/2，所述L π为MMI波导中两个最低阶模式的拍长。
  15. 根据权利要求14所述的光功率调节装置，其特征在于，不同光功率调节模块中MMI的多模干涉区长度不同。
  16. 根据权利要求12至15中任一项所述的光功率调节装置，其特征在于，所述第K个光功率调节模块还包括多个光分束器，所述控制装置包括M个控制模块，所述第K个光功率调节模块中每个MMI的2M-K+1个输入端口分别与2M-K+1个光分束器的第一输出端口连接，所述2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，所述第K个控制模块分别与所述第K个光功率调节模块中的每个移相器电连接；
    每个所述光分束器用于对输入的光信号进行分路，分路后的其中一路光信号输出至与每个所述光分束器对应的MMI，分路后的另一路光信号输出至所述第K个控制模块；
    所述第K个控制模块用于对输入的光信号进行检测，并根据所述检测的结果调节所述第K个光功率调节模块中的每个移相器。
  17. 根据权利要求16所述的光功率调节装置，其特征在于，所述第K个控制模块包括2M-K个耦合器、2M-K个光探测器和2M-K相位控制单元，所述第I个输入端口与第I个光分束器的第一输出端口连接，所述第2M-K+1-I+1个输入端口与所述第2M-K+1-I+1个光分束器的第一输出端口连接，所述第I个光分束器的第二输出端口和所述第2M-K+1-I+1个光分束器的第二输出端口与所述第J个耦合器的输入端口连接，1≤所述J≤2M-K，所述第J个耦合器输出端口与所述第J个光探测的输入端口连接，所述第J个光探测器的输出端口与所述相位控制单元的输入端口电连接，所述相位控制单元的输出端口与所述第K个光功率调节模块中的每个移相器电连接；
    所述第J个耦合器用于对输入的光信号进行耦合；
    所述第J个光探测器用于对所述耦合后的光信号进行检测；
    所述相位控制单元用于根据所述第J个光探测器的检测结果调节所述第K个光功率调节模块中的第I个移相器，所述第I个移相器与所述第I个输入端口或所述第2M-K+1-I+1个输入端口连接。
  18. 根据权利要求12至15中任一项所述的光功率调节装置，其特征在于，所述第K个光功率调节模块还包括多个光分束器，所述控制装置包括M个控制模块，所述第K个光功率调节模块中每个MMI的2M-K+1个输出端口分别与2M-K+1个光分束器的输入端口连接，所述2M-K+1个光分束器的第一输出端口与第K+1个光功率调节模块中2K个MMI的输入端口连接，所述2M-K+1个光分束器的第二输出端口都与第K个控制模块连接，所述第K个控制模块分别与所述第K个光功率调节模块中的每个移相器电连接；
    每个所述分束器用于对输入的光信号进行分路，分路后的其中一路光信号输出至第K+1个光功率调节模块中与每个所述分束器对应的MMI，分路后的另一路光信号输出至所述第K个控制模块；
    所述第K个控制模块用于对输入的光信号进行检测，并根据所述检测的结果调节所述第K个光功率调节模块中的每个移相器。
  19. 根据权利要求18所述的光功率调节装置，其特征在于，所述第K个控制模块包括2M-K+1个光探测器和2M-K相位控制单元，所述2M-K+1个光分束器的第二输出端口与所述2M-K+1个光探测器的输入端口连接，所述2M-K+1个光探测器的输出端口都与所述相位控制单元的输入端口电连接，所述相位控制单元的输出端口与所述第K个光功率调节模块中的每个移相器电连接；
    第I个光探测器用于检测输入的光信号，所述第I个光探测器的输入端口与第I个光分束器的第二输出端口连接；
    第2M-K+1-I+1个光探测器用于检测输入的光信号，所述第2M-K+1-I+1个光探测器的输入端口与第2M-K+1-I+1个光分束器的第二输出端口连接；
    所述相位控制单元用于根据所述第I个光探测器和所述第2M-K+1-I+1个光探测器的检测结果调节所述第K个光功率调节模块中的第I个移相器，所述第I个移相器与所述第I个输入端口或所述第2M-K+1-I+1个输入端口连接；
    每个所述光探测器用于检测输入的光信号；
    所述相位控制单元用于根据每个所述光探测器的检测结果调节所述第K个光功率调节模 块中的每个移相器。
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US6178276B1 (en) * 1999-04-05 2001-01-23 United States Of America As Represented By The Secretary Of The Army End-pumped waveguide optical splitter-amplifiers based on self-imaging
US20050094923A1 (en) * 2003-10-13 2005-05-05 Korea Institute Of Science And Technology Integrated optical isolator using multi-mode interference structure
CN104914506A (zh) * 2015-06-23 2015-09-16 中国科学院半导体研究所 基于多模干涉耦合器的InP基模分复用/解复用器结构
CN108923858A (zh) * 2018-07-19 2018-11-30 湖北捷讯光电有限公司 一种硅基波导光学混频器装置

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US6178276B1 (en) * 1999-04-05 2001-01-23 United States Of America As Represented By The Secretary Of The Army End-pumped waveguide optical splitter-amplifiers based on self-imaging
US20050094923A1 (en) * 2003-10-13 2005-05-05 Korea Institute Of Science And Technology Integrated optical isolator using multi-mode interference structure
CN104914506A (zh) * 2015-06-23 2015-09-16 中国科学院半导体研究所 基于多模干涉耦合器的InP基模分复用/解复用器结构
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