Multi-mode coherent Mach-Zehnder optical interferometer and control method thereof

Abstract

The invention discloses a multi-mode coherent Mach-Zehnder optical interferometer and a control method thereof, and the interferometer comprises a first beam splitter which comprises M input ends and N output ends, the input ends of the first beam splitter are used for receiving multi-mode light, and the output ends of the first beam splitter are used for outputting beam-split multi-mode light which carries out the beam splitting of the energy of the multi-mode light; the input end of each multi-mode phase shift area is connected with the output end of the first beam splitter, the input end of each multi-mode phase shift area is used for receiving the beam splitting multi-mode light, the multi-mode phase shift areas carry out the same optical phase compensation on all modes of the beam splitting multi-mode light processed by the multi-mode phase shift areas, and the output end of each multi-mode phase shift area is used for outputting the processed multi-mode light; and the second beam splitter comprises N input ends and L and output ends, the input ends of the second beam splitter are connected with the output end of the multimode phase shift area, the input ends of the second beam splitter are used for receiving the processed multimode light, and the output end of the second beam splitter is used for outputting the combined multimode light. According to the invention, the function of multi-mode light coherence can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated optics, and in particular relates to a multi-mode coherent Mach-Zehnder optical interferometer and a control method thereof. Background Art

[0002] Mach-Zehnder (MZ) optical interference structure is a commonly used coherent light control device. By applying different electrical signals to two parallel arms and changing the phase difference between the two beams at the output beam splitter, the amplitude or phase modulation of the input optical signal can be achieved. Among them, mode multiplexing is a multiplexing technology that uses multiple spatial modes as information carriers, which can improve the transmission capacity and processing power of optical signals.

[0003] The traditional Mach-Zehnder interferometer structure can only process single-mode input signals. Due to the different mode fields and effective refractive indices between different modes, it is impossible to achieve consistent coherent modulation at the same time. Currently, there is a mode diversity solution, which is to first demultiplex multiple modes to convert them into single modes, then modulate each single mode, and finally multiplex them; this requires the number of interference control devices to increase exponentially (since each mode is modulated separately, the number of devices required doubles according to the number of modes), resulting in a complex coherent modulation structure.

[0004] Therefore, how to simultaneously achieve consistent coherent modulation of multiple modes in integrated optics is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a multi-mode coherent Mach-Zehnder interferometer and a control method thereof. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a multi-mode coherent Mach-Zehnder interferometer, comprising:

[0007] A first beam splitter includes M input ends and N output ends, M≥1, N≥2, the input end of the first beam splitter is used to receive the multimode light, and the output end of the first beam splitter is used to output a split multimode light that splits the energy of the multimode light; wherein the mode of the multimode light is P, P≥2, and the mode order of the split multimode light is the same as that of the multimode light;

[0008] N multimode phase shift zones, each of which includes an input end and an output end, the input end of the multimode phase shift zone is connected to the output end of the first beam splitter, the input end of the multimode phase shift zone is used to receive the split multimode light, the multimode phase shift zone has the same optical phase compensation for all modes of the split multimode light processed by it, and the output end of the multimode phase shift zone is used to output the processed multimode light;

[0009] The second beam splitter includes N input ends and L output ends, L≥2, the input end of the second beam splitter is connected to the output end of the multi-mode phase shift zone, the input end of the second beam splitter is used to receive the processed multi-mode light, and the output end of the second beam splitter is used to output the combined multi-mode light.

[0010] In a second aspect, the present invention further provides a control method for a multi-mode coherent Mach-Zehnder interferometer, comprising:

[0011] Obtain multimode light;

[0012] Inputting the multimode light into the first beam splitter for energy splitting to obtain a plurality of split multimode lights; wherein the mode order of the split multimode light is the same as the mode order of the multimode light;

[0013] Inputting the split multimode light into the multimode phase shift region, performing phase compensation on all modes of light of the split multimode light, so that the phases of all modes of light of the split multimode light are the same, and obtaining processed multimode light;

[0014] The processed multi-mode light is input to the second beam splitter for energy combination to obtain combined multi-mode light.

[0015] Beneficial effects of the present invention:

[0016] The present invention provides a multi-mode coherent Mach-Zehnder interferometer and a control method thereof, wherein a first beam splitter splits the energy of a multi-mode light, outputs the split multi-mode light through an output end, and keeps the mode order at the time of input unchanged, and the energy splitting may be equal or not, but the output split multi-mode light has the same mode order as the multi-mode light. A multi-mode phase shift zone is used to process the split multi-mode light, and it can also be understood that the number of output ends of the first beam splitter is equal to the number of multi-mode phase shift zones, and the multi-mode phase shift zone has the same optical phase compensation for all modes of the split multi-mode light, that is, all modes of the split multi-mode light are mutually converted in different modes in a waveguide, and finally each mode of light experiences the same phase, and the processed multi-mode light is output, and the processed multi-mode light is input to a second beam splitter for beam combining, and the combined multi-mode light is output; in this way, mode diversity is not required, and simultaneous modulation of multiple modes is achieved.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a schematic diagram of a multi-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention;

[0019] Figure 2 is another schematic diagram of a multi-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention;

[0020] Figure 3 It is a flow chart of a control method of a multi-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention;

[0021] Figure 4 It is a schematic diagram of a control method of a dual-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention;

[0022] Figure 5 It is a schematic diagram of a control method of a three-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram of a dual-mode coherent 1×1 optical attenuator, a 1×2 optical switch and a 2×2 optical switch provided in an embodiment of the present invention;

[0024] Figure 7 It is a structural schematic diagram of a dual-mode arbitrary-proportion arbitrary-phase coherent light generation solution provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0026] See also Figure 1 , Figure 1 is a schematic diagram of a multi-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention. The multi-mode coherent Mach-Zehnder interferometer provided by the present invention includes:

[0027] The first beam splitter 10 includes M input ends and N output ends, M≥1, N≥2, the input end of the first beam splitter 10 is used to receive the multimode light, and the output end of the first beam splitter 10 is used to output the split multimode light by splitting the energy of the multimode light; wherein the mode of the multimode light is P, P≥2, and the mode order of the split multimode light is the same as that of the multimode light;

[0028] N multimode phase shift zones 20, each of which includes an input end and an output end. The input end of the multimode phase shift zone 20 is connected to the output end of the first beam splitter 10. The input end of the multimode phase shift zone 20 is used to receive the split multimode light. The multimode phase shift zone 20 performs the same optical phase compensation for all modes of the split multimode light processed by it. The output end of the multimode phase shift zone 20 is used to output the processed multimode light.

[0029] The second beam splitter 30 includes N input ends and L output ends, L≥2. The input end of the second beam splitter 30 is connected to the output end of the multi-mode phase shift zone 20. The input end of the second beam splitter 30 is used to receive the processed multi-mode light, and the output end of the second beam splitter 30 is used to output the combined multi-mode light.

[0030] For more details, please see Figure 1 The multi-mode coherent Mach-Zehnder interferometer provided in this embodiment includes a first beam splitter 10, a multi-mode phase shift region 20 and a second beam splitter 30. The multi-mode phase shift region 20 is arranged between the first beam splitter 10 and the second beam splitter 30. The first beam splitter 10 is used to split the multi-mode light. The multi-mode phase shift region 20 is used to process the split multi-mode light output by the first beam splitter 10 and output the processed multi-mode light. The processed multi-mode light is then combined by the second beam splitter 30.

[0031] Among them, the first beam splitter 10 includes M (M≥1) input ports and N (N≥2) output ports, and both the input port and the output port support P modes of multi-mode light. When multi-mode light is input at any input port, the first beam splitter 10 splits the energy of the multi-mode light, outputs the split multi-mode light through N output ports, and keeps the mode order at the time of input unchanged. The energy splitting can be equal or not, but the output split multi-mode light has the same mode order as the multi-mode light. The multi-mode phase shift zone 20 is used to process the split multi-mode light, and it can also be understood that the number of output ports of the first beam splitter 10 is equal to the number of multi-mode phase shift zones 20, and the multi-mode phase shift zone 20 has the same optical phase compensation for all modes of the split multi-mode light, and outputs the processed multi-mode light, which is input to the second beam splitter 30 for beam combining, and outputs the combined multi-mode light; in this way, mode diversity is not required, and simultaneous modulation of multiple modes is achieved.

[0032] It should be noted that, due to optical reciprocity, the input ends of the first beam splitter 10 and the second beam splitter 30 can also be used as output ends, and the output ends can also be used as input ends.

[0033] In an optional embodiment of the present invention, the multimode phase shift region 20 includes P sections of optical waveguides 21 and P-1 first mode converters 22 located between adjacent optical waveguides 21 , and an optical phase shifter 23 is disposed on each section of the optical waveguide 21 .

[0034] For more details, please see Figure 1 In this embodiment, the optical waveguide 21 supports the transmission of P modes of split multimode light, and realizes lossless transmission with unchanged mode order as much as possible; the first mode converter 22 includes 1 input end and 1 output end, both of which support the conversion of P modes of split multimode light, and after the conversion, both the input and output maintain P modes; the optical phase shifter 23 is used to adjust the effective refractive index of the optical waveguide 21, and is composed of an electrode or a hot electrode. In this embodiment, a single optical phase shifter 23 is not required to be mode-coherent.

[0035] In this embodiment, considering that the split multi-mode light includes P modes and needs to be converted P-1 times, P-1 first mode converters 22 are set to achieve light conversion of all modes of the split multi-mode light, so that the phase experienced by each mode of light is the same, and further realize multi-mode simultaneous modulation.

[0036] In an optional embodiment of the present invention, the lengths of the P-segment optical waveguides 21 are equal.

[0037] In an optional embodiment of the present invention, please continue to refer to Figure 1 , and combined with Figure 2 , Figure 2 is another schematic diagram of a multi-mode coherent Mach-Zehnder interferometer provided by an embodiment of the present invention, further comprising: a plurality of second mode converters 40, including an input end and an output end;

[0038] The input end of the second mode converter 40 is used to receive the light to be processed, and the output end of the second mode converter 40 is connected to the input end of the first beam splitter 10 to output multi-mode light;

[0039] Alternatively, the input end of the second mode converter 40 is connected to the output end of the second beam splitter 30 for receiving the combined multi-mode light, and the output end of the second mode converter 40 is used to output processed light of the same mode order as the light to be processed.

[0040] For more details, please see Figure 1 and Figure 2 A second mode converter 40 is provided before the input end of the first beam splitter 10 or after the output end of the second beam splitter 30, for transforming the transformed mode once, so that the overall input and output mode order and arrangement remain unchanged, so as to ensure that the multi-mode order remains unchanged and is the same as the original one.

[0041] In an optional embodiment of the present invention, the output end of the first beam splitter 10 corresponds one-to-one to the input end of the multimode phase shift region 20 , and the output end of the multimode phase shift region 20 corresponds one-to-one to the input end of the second beam splitter 30 .

[0042] For more details, please see Figure 1 or Figure 2 In this embodiment, the number of input ports included in the first beam splitter 10 is M A , the number of output terminals is N A The number of input ports included in the second beam splitter 30 is M B , the number of output terminals is N B , M B =N A≥2, and both the first beam splitter 10 and the second beam splitter 30 support P modes, the output end of the first beam splitter 10 corresponds to the multi-mode phase shift region 20 one-to-one, and the multi-mode phase shift region 20 corresponds to the second beam splitter 30 one-to-one.

[0043] Based on the same inventive concept, see Figure 3 , Figure 3 1 is a flow chart of a control method of a multi-mode coherent Mach-Zehnder interferometer provided in an embodiment of the present invention, which is used to control the Mach-Zehnder interferometer provided in the above embodiment of the present invention. The embodiment of the Mach-Zehnder interferometer is referred to above and will not be described in detail here. The control method includes:

[0044] S101, obtaining multimode light;

[0045] S102, inputting the multimode light into the first beam splitter 10 for energy splitting to obtain a plurality of split multimode lights; wherein the mode order of the split multimode lights is the same as the mode order of the multimode light;

[0046] S103, inputting the split multimode light into the multimode phase shift region 20, performing phase compensation on the light of all modes of the split multimode light, so that the phases of the light of all modes of the split multimode light are the same, and obtaining processed multimode light;

[0047] S104 , input the processed multi-mode light into the second beam splitter 30 for energy combination to obtain combined multi-mode light.

[0048] For more details, please see Figure 3 , and combined with Figure 1 and Figure 2 As shown, the first beam splitter 10 splits the energy of the multimode light, outputs the split multimode light through the output end, and keeps the mode order at the time of input unchanged. The energy splitting can be evenly divided or not evenly divided, but the output split multimode light has the same mode order as the multimode light. The multimode phase shift zone 20 is used to process the split multimode light. It can also be understood that the number of output ends of the first beam splitter 10 is equal to the number of multimode phase shift zones 20, and the multimode phase shift zone 20 has the same optical phase compensation for all modes of the split multimode light, that is, all modes of the split multimode light are converted to each other in different modes in the waveguide, and finally each mode of light experiences the same phase, and the processed multimode light is output, and the processed multimode light is input to the second beam splitter 30 for beam combining, and the combined multimode light is output; in this way, mode diversity is not required, and simultaneous modulation of multiple modes is achieved.

[0049] In an optional embodiment of the present invention, the split multimode light is input into the multimode phase shift region 20, and phase compensation is performed on all modes of light of the split multimode light so that the phases of all modes of light of the split multimode light are the same, thereby obtaining the processed multimode light, including:

[0050] Input the split multimode light into the optical waveguide 21 of the multimode phase shift region 20, transmit it to the first mode converter 22 for conversion, use any mode of the split multimode light as the conversion starting light, convert the conversion starting light into a mode of the split multimode light except the conversion starting light, until after the conversion by a plurality of the first mode converters 22, all the modes of the split multimode light except the conversion starting light are converted once;

[0051] All modes of the split multi-mode light are used as conversion starting light for conversion to obtain processed multi-mode light.

[0052] Specifically, in this embodiment, the optical waveguide 21 of the multimode phase shift zone 20 transmits the split multimode light, the first mode converter 22 is used to convert the order of light, and the optical phase shifter 23 is used to adjust the effective refractive index of the optical waveguide 21. After all modes of light of the split multimode light pass through the multimode phase shift zone 20 for phase compensation, the phase experienced by each mode of light is the same, that is, by converting each mode of the split multimode light in the waveguide, for each mode of light, all modes of light except the light of its own mode are converted once, so that the phase shift experienced by each mode of light is the same, thereby balancing the optical path of each mode, and thus realizing the function of multi-mode synchronization.

[0053] For example, Figure 4 As shown, Figure 4 1 is a schematic diagram of a control method of a dual-mode coherent Mach-Zehnder interferometer provided in an embodiment of the present invention. Assuming that the multimode light is dual-mode light, after being processed by the first beam splitter 10, the beams are split into N A A beam of dual-mode light enters the same multi-mode phase shift region 20, wherein the dual-mode light includes TE0 mode light and TE1 mode light, respectively. The TE0 mode light is used as the conversion starting light. The TE0 mode light is converted into TE1 mode light by the first mode converter 22, and then the TE1 mode light passes through the optical phase shifter 23, and the phase experienced is: ψ TE0 +ψ TE1 TE1 mode light is used as the conversion starting light, TE1 mode light is converted into TE0 mode light by the first mode converter 22, and then TE0 mode light passes through the optical phase shifter 23, and the phase experienced is: ψ TE1 +ψ TE0 It can be seen that, although the phase shifts of TE0 mode light and TE1 mode light are different for each phase shifter, the total phase shift of each mode of light is the same after passing through the entire multi-mode phase shift region 20, thus achieving a multi-mode consistent simultaneous regulation function.

[0054] For example, Figure 5 As shown, Figure 51 is a schematic diagram of a control method of a three-mode coherent Mach-Zehnder interferometer provided in an embodiment of the present invention. Assuming that the multimode light is a three-mode light, after being processed by the first beam splitter 10, the beam is split into N A The three-mode light beams enter the same multimode phase shift region 20 respectively, wherein the three-mode light includes TE0 mode light, TE1 mode light and TE2 mode light respectively, and the TE0 mode light is used as the conversion starting light. The TE0 mode light is converted into TE1 mode light by the first first mode converter 22, and then the TE1 mode light passes through the optical phase shifter 23, and then the TE2 mode light passes through the optical phase shifter 23, and the phase experienced is: ψ TE0 +ψ TE1 +ψ TE2 ; Taking the TE1 mode light as the conversion starting light, the TE1 mode light is converted into the TE2 mode light through the first first mode converter 22, and then the TE2 mode light passes through the optical phase shifter 23, and then the second first mode converter 22 is converted into the TE0 mode light, and then the TE0 mode light passes through the optical phase shifter 23, and the phase experienced is: ψ TE1 +ψ TE2 +ψ TE0 ; Taking the TE2 mode light as the conversion starting light, the TE2 mode light is converted into the TE0 mode light through the first first mode converter 22, and then the TE0 mode light passes through the optical phase shifter 23, and then the second first mode converter 22 is converted into the TE1 mode light, and then the TE1 mode light passes through the optical phase shifter 23, and the phase experienced is: ψ TE2 +ψ TE0 +ψ TE1 ; It can be seen that all modes of light in the split multimode light undergo simultaneous phase modulation through the multimode phase shift zone 20, and each mode of light undergoes the same phase. The processed multimode light obtained is combined by the second beam splitter 30, and the phase of each processed multimode light directly affects the field intensity and phase at the output end of the second beam splitter 30.

[0055] It should be noted that the above embodiments only schematically illustrate the specific process of dual-mode light and triple-mode light. Of course, other multi-mode lights can also be implemented according to the above process. The core idea is to make the phase experienced by each mode of the split multi-mode light the same, so as to realize the function of multi-mode consistent and simultaneous regulation.

[0056] In an optional embodiment of the present invention, after the split multimode light is converted by the multiple first mode converters 22 of the multimode phase shift region 20, the processed multimode light obtained has the same mode as the split multimode light.

[0057] In an optional embodiment of the present invention, the phase compensation of the light of the pth mode of the split multimode light is The expression is:

[0058]

[0059] in, represents the effective refractive index change amount of the optical phase shifter 23 provided on the optical waveguide 21, L / P represents the length of each section of the optical waveguide 21, 2π / λ0 represents the wave number, P represents the number of all modes of the split multimode light, and the product of the three is the change amount of the phase (optical path) in the waveguide. Since each mode has achieved traversal in the optical phase shift region, the order of the summation process can be rearranged, which is equal to the sum of the effective refractive index changes from the first mode to the pth mode (i.e., all modes).

[0060] It can also be understood that, based on the modulation principle of the multimode MZI, in order to achieve multimode coherence, it is only necessary to prove that in the N multimode phase shift regions 20, the respective mode phases are modulated simultaneously. The above process shows that the total phase shift of any given input mode is the sum of the phase shifts of all modes in each segment of the multimode waveguide. When the same mode in each multimode waveguide has the same phase shift, this phase shift remains unchanged for any TEp mode, thereby achieving mode-independent characteristics.

[0061] Furthermore, an additional mode converter is required after the MZI structure to restore the mode order.

[0062] In an optional embodiment of the present invention, it also includes:

[0063] Before the multi-mode light is input to the first beam splitter 10 for energy splitting, the multi-mode light is subjected to mode conversion using a second mode converter 40;

[0064] Alternatively, after obtaining the combined multi-mode light, the second mode converter 40 is used to perform mode conversion on the combined multi-mode light.

[0065] Specifically, in the present embodiment, after being processed by the multi-mode phase shift zone 20 and the second beam splitter 30, the order of the mode changes relative to the split multi-mode light input to the multi-mode phase shift zone 20. Therefore, after being combined by the second beam splitter 30, it is necessary to perform another mode conversion through the second mode converter 40 to convert the mode of the overall interference output into the mode of the multi-mode light originally input to the first beam splitter 10; of course, this process can also be implemented in the second mode converter 40 before the first beam splitter 10, by first changing the mode order, and then directly converting it to the original mode after being processed by the multi-mode phase shift zone 20.

[0066] In an optional embodiment of the present invention, see Figure 6 , Figure 6 It is a schematic diagram of a dual-mode coherent 1×1 optical attenuator, a 1×2 optical switch and a 2×2 optical switch provided in an embodiment of the present invention, and provides a dual-mode coherent MZ optical interference structure based on silicon-based integrated photonics, including a dual-mode first beam splitter 10, a multi-mode phase shift zone 20 and a dual-mode second beam splitter 30, wherein the multi-mode phase shift zone 20 includes two sections of optical waveguides 21, a first mode converter 22 is arranged between the two sections of optical waveguides 21, and phase shifters are respectively arranged on the two sections of optical waveguides 21; the dual-mode first beam splitter 10 splits the input dual-mode light, and the splitting ratio is an arbitrary ratio of 0:1 to 1:0, and the splitting process keeps the order of the mode unchanged, that is, TE0 is still TE0 mode after splitting, and TE1 is still TE1 mode after splitting; further, according to the principle described above, the multi-mode phase shift zone 20 performs phase compensation on each mode of the split multi-mode light, so that the phase experienced by each mode of light is the same, and the multi-mode light suppresses the coherence process.

[0067] Optionally, the dual-mode optical beam splitter can be a dual-mode multimode interference coupler of silicon waveguide, a dual-mode directional coupler, a reverse-designed dual-mode beam splitter, etc.

[0068] Optionally, the dual-mode waveguide may be a TEx0 type (x=0, 1) dual-mode waveguide with a widened lateral width, a TE0x type waveguide with a widened longitudinal width, or a TE0 and TE1 waveguide of a Bloch mode in a photonic crystal.

[0069] The TE0 and TE1 mode converter converts the input TE0 mode into the TE1 mode and converts the input TE1 mode into the TE0 mode.

[0070] Optionally, the first mode converter 22 may be based on a silicon waveguide asymmetric directional coupler or an inverse design.

[0071] Optionally, the phase shifter can be an electro-optical phase shifter 23 based on a P / N doped waveguide, or a thermal phase shifter composed of a doped waveguide and a metal / sleeve magnetic hot pole based on a thermal effect. The function of the phase shifter is to phase shift the light field in the multimode waveguide by regulating the refractive index of the multimode waveguide. The phase shifter of the present invention does not require the same modulation for the TE0 and TE1 modes.

[0072] In this embodiment, Figure 6 As shown, the number of ports of the multimode optical splitter can be 1-2 or 2-2. When the number of input and output ports is 1-2, the phase shifter is a thermo-optical tuning device and can be used as a dual-mode optical attenuator. The phase shifter is an electro-optical tuning device and can be used as a dual-mode electro-optical modulator.

[0073] When the number of input and output ports is 1-1 and 1-2 respectively, the device can be used as a dual-mode 1×2 optical switch. Devices with thermal-optical modulation can be used in low-speed optical networks, while devices with electro-optical modulation can be used for high-speed routing.

[0074] When the number of input and output ports is 2-2, the device can be used as a dual-mode 2×2 optical switch, as a basic building block of a large-scale on-chip dual-mode optical switch network, and used in optical networks such as Benes and Fat-Tree.

[0075] It should be noted that this embodiment does not limit the mode of the multi-mode light, and in fact any orthogonal mode is acceptable.

[0076] In an optional embodiment of the present invention, see Figure 7 , Figure 7 It is a structural schematic diagram of a dual-mode arbitrary-ratio arbitrary-phase coherent light generation scheme provided by an embodiment of the present invention, and provides a dual-mode coherent arbitrary-ratio arbitrary-phase coherent light splitting scheme based on a silicon-based integrated photonic dual-mode coherent MZ optical interference structure, in which the entire multi-mode optical phase shift zone is used instead of a mode converter at the output end of the overall 2×2 interference structure.

[0077] Optionally, the dual-mode beam splitter has a 50:50 splitting ratio, and the beam splitting process keeps the mode order unchanged.

[0078] Optionally, all output ends of the overall interference structure are provided with multi-mode light phase shift zones, that is, both output ends are provided with multi-mode light phase shift zones, and some output ends of the overall interference structure are provided with multi-mode light phase shift zones, that is, one output end is provided with a multi-mode light phase shift zone, and the other output end is still provided with a mode converter.

[0079] In this embodiment, the 2×2 interference structure can generate light splitting with any splitting ratio. Since a dual-mode coherent interference structure is adopted, the splitting ratios of the two modes are consistent. A multi-mode phase shift region 20 is used at the output end to replace the mode converter. On the one hand, the mode conversion effect is achieved, and the final output light mode is restored to the input mode. On the other hand, an additional phase is added to achieve arbitrary phase adjustment between the two outputs. The device is always dual-mode coherent during operation.

[0080] It should be noted that when two multi-mode phase shift regions 20 are added before the input end of the MZ interference structure, the overall device can be used as a dual-mode coherent photosynthesis solution with arbitrary proportion and arbitrary phase.

[0081] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0083] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A multi-mode coherent Mach-Zehnder interferometer, characterized in that: include: A first beam splitter, comprising M input ends and N output ends, M≥1, N≥2, the input end of the first beam splitter is used to receive multimode light, and the output end of the first beam splitter is used to output split multimode light by splitting the energy of the multimode light; wherein the mode of the multimode light is P, P≥2, and the split multimode light has the same mode order as the multimode light; N multimode phase shift zones, each of which comprises an input end and an output end, the input end of the multimode phase shift zone is connected to the output end of the first beam splitter, the input end of the multimode phase shift zone is used to receive the split multimode light, the multimode phase shift zone processes the same optical phase compensation for all modes of the split multimode light, and the output end of the multimode phase shift zone is used to output the processed multimode light; The second beam splitter includes N input ends and L output ends, L≥1, the input end of the second beam splitter is connected to the output end of the multi-mode phase shift zone, the input end of the second beam splitter is used to receive the processed multi-mode light, and the output end of the second beam splitter is used to output the combined multi-mode light.

2. The multi-mode coherent Mach-Zehnder interferometer according to claim 1, characterized in that: The multimode phase shift region includes P sections of optical waveguides and P-1 first mode converters located between adjacent optical waveguides, and an optical phase shifter is arranged on each section of the optical waveguide.

3. The multi-mode coherent Mach-Zehnder interferometer according to claim 2, characterized in that: The lengths of the optical waveguides in the P segments are equal.

4. The multi-mode coherent Mach-Zehnder interferometer according to claim 1, characterized in that: Also includes: a plurality of second mode converters including an input terminal and an output terminal; The input end of the second mode converter is used to receive the light to be processed, and the output end of the second mode converter is connected to the input end of the first beam splitter to output the multi-mode light; Alternatively, the input end of the second mode converter is connected to the output end of the second beam splitter for receiving the combined multi-mode light, and the output end of the second mode converter is used to output processed light of the same mode order as the light to be processed.

5. The multi-mode coherent Mach-Zehnder interferometer according to claim 1, characterized in that: The output end of the first beam splitter corresponds one-to-one to the input end of the multi-mode phase shift region, and the output end of the multi-mode phase shift region corresponds one-to-one to the input end of the second beam splitter.

6. A control method for a multi-mode coherent Mach-Zehnder interferometer, characterized in that: include: Obtain multimode light; Inputting the multimode light into a first beam splitter for energy splitting to obtain a plurality of split multimode lights; wherein the mode order of the split multimode lights is the same as the mode order of the multimode light; Inputting the split multimode light into a multimode phase shift region, performing phase compensation on all modes of light of the split multimode light, so that the phase compensation of all modes of light of the split multimode light is the same, and obtaining processed multimode light; The processed multi-mode light is input to a second beam splitter for energy combination to obtain combined multi-mode light.

7. The control method of the multi-mode coherent Mach-Zehnder interferometer according to claim 6, characterized in that: Inputting the split multimode light into a multimode phase shift region, performing phase compensation on all modes of light of the split multimode light so that the phases of all modes of light of the split multimode light are the same, and obtaining processed multimode light, comprising: Input the split multimode light into the optical waveguide of the multimode phase shift zone, transmit it to the first mode converter for conversion, use any mode of the split multimode light as the conversion starting light, convert the conversion starting light into a mode of the split multimode light except the conversion starting light, until the light of the mode of the split multimode light except the conversion starting light is converted once after conversion by multiple first mode converters; All modes of the split multi-mode light are used as conversion starting light for conversion to obtain processed multi-mode light.

8. The control method of the multi-mode coherent Mach-Zehnder interferometer according to claim 7, characterized in that: After the split multi-mode light is converted by the multiple first mode converters in the multi-mode phase shift zone, the processed multi-mode light obtained has the same mode as the split multi-mode light.

9. The control method of the multi-mode coherent Mach-Zehnder interferometer according to claim 6, characterized in that: Phase compensation of the p-th mode of the split multimode light The expression is: in, represents the effective refractive index change of the optical waveguide provided with an optical phase shifter, L / P represents the length of each section of the optical waveguide, 2π / λ0 represents the wave number, and P represents the number of all modes of the split multimode light.

10. The control method of the multi-mode coherent Mach-Zehnder interferometer according to claim 6, characterized in that: Also includes: Before the multi-mode light is input into the first beam splitter for energy splitting, the multi-mode light is subjected to mode conversion using a second mode converter; Alternatively, after obtaining the combined multi-mode light, a second mode converter is used to perform mode conversion on the combined multi-mode light.

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