Multi-port optical switch based on phase change material and nonvolatile regulation and control

Abstract

The invention discloses a multi-port optical switch based on a phase change material and nonvolatile regulation and control. Different combination states of the phase-change material units are realized by arranging the plurality of phase-change material units and by means of crystal form control of the phase-change material units, so that a transmission path of an optical signal in a multimode interference region is changed, full logic mapping of the optical signal at a plurality of output ports and input ports is realized, and the optical switch supports a 1 * N or M * N optical switch matrix. A plurality of basic units do not need to be connected in series or in parallel, so that high-integration-level implementation of an integrated circuit is facilitated, and a foundation is provided for subsequent large-scale extension. Meanwhile, the phase change material is adopted to regulate and control the multimode interference area of the optical switch, power consumption can be remarkably reduced, and the optical switch is suitable for long-term stable optical path configuration and has the advantages of being small in size, high in integration degree, high in switching rate and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of integrated photonic signal processing, and particularly relates to a multi-port optical switch based on phase change material and non-volatile regulation. BACKGROUND

[0002] With the comprehensive promotion of 5G commercialization and the acceleration of 6G technology research and development, optical communication networks are iterating towards the direction of "ultra-high speed, large capacity, low delay, and low power consumption". As the core unit for data exchange in optical switching networks, optical switches can switch data and signals in multi-mode channels, and are essential for building more flexible and effective mode division multiplexing networks and realizing the all-optical network function of silicon-based chips. Most of the current multi-port optical switches are based on thermal-optic effect, which changes the local temperature through a micro-heater to cause a change in refractive index, thereby realizing optical path control. Although this method can realize a certain scale of multi-port switching, it still has the following problems: 1. High power consumption: The refractive index distribution needs to be continuously heated to maintain, and the typical power consumption is in the range of milliwatts to hundreds of milliwatts, which is difficult to meet the needs of low-power optical interconnection and optical computing systems. 2. Limited response speed: The thermal diffusion time is relatively long, and the switching time is usually in the millisecond level, making it difficult to achieve high-speed optical path switching. 3. Non-volatility is insufficient: The state is lost after the power is turned off, and the power-off memory function cannot be realized, limiting its application in reconfigurable optical networks. 4. Limited integration: Thermal-optic switches usually require a large heating area and thermal isolation structure, which is not conducive to high-density integration. Therefore, the existing thermal-optic scheme cannot meet the future needs of low-power, high-speed, scalable, and non-volatile optical interconnection and optical computing.

[0003] In addition, some existing technologies use phase change material films in optical switches for phase shift units of optical waveguide switches to make reconfigurable mode multiplexing optical waveguide switch unit devices. However, the existing optical switches based on phase change materials can provide fewer multiplexing modes and port numbers. If more data needs to be transmitted, a larger optical switch needs to be expanded and more components need to be combined. SUMMARY

[0004] To solve the above technical problems, the present application provides a multi-port optical switch based on phase change material and non-volatile regulation, which utilizes the different refractive index characteristics of phase change material in different states to change the propagation path of optical signals in the multimode interference region, thereby adjusting the output path of optical signals and outputting optical signals from more different ports, realizing the functions of multi-channel selection input, output and mode switching of optical signals by the optical switch, and forming an MxN type multi-port optical waveguide switch.

[0005] In order to achieve the purpose of the present application, the present application provides the following technical solutions: A multi-port optical switch based on phase change material and non-volatile regulation, comprising an input waveguide, a multi-mode interference region and an output waveguide, the multi-mode interference region being located between the input waveguide and the output waveguide; after an optical signal is input from a port of the input waveguide, the optical signal enters the multi-mode interference region, and after signal modulation of the multi-mode interference region, the optical signal is output from a port of the output waveguide; the structure of the multi-mode interference region from bottom to top is in turn a substrate, a substrate, a waveguide on the substrate and a phase change material unit, the phase change material unit is arranged on the waveguide of the multi-mode interference region, the length of the phase change material unit is 5-20 μm, the width is 0.5-2.5 μm, and the thickness is 20-50 nm, and the arrangement position of the phase change material unit is arranged according to the following steps and methods: 1. A structure model of the multi-mode interference region is established, a two-dimensional intensity distribution diagram of the optical field in the multi-mode interference region is obtained by simulation, and according to the intensity, an energy gathering point in the propagation direction of the optical field in the multi-mode interference region is extracted, and one energy gathering point corresponds to one light intensity maximum point; 2. According to the requirement that the intensity is from large to small, the center coordinates (n-x i , n-y i ) of n light intensity maximum points are extracted, wherein n represents the nth light intensity maximum point, the light intensity of the nth light intensity maximum point is arranged in order from large to small according to the light intensity of each energy gathering point extracted from the two-dimensional intensity distribution diagram, and the order is in the nth position; x i is the longitudinal coordinate of the nth light intensity maximum point in the multi-mode interference region along the propagation direction, and y i is the transverse offset of the nth light intensity maximum point in the multi-mode interference region; 3. The first n light intensity maximum points are selected as the center points of the arrangement of the phase change material units, the center point coordinates of the nth phase change material unit are the center coordinates (n-x i , n-y i ) of the nth light intensity maximum point selected, and the phase change material units are arranged on the waveguide of the multi-mode interference region according to the center point coordinates of the phase change material units.

[0006] Further, compared with the coordinates (n-x i , n-y i ) of the nth light intensity maximum point, the transverse and longitudinal offset distances of the center point coordinates of the nth phase change material unit are controlled within ±0.5 μm.

[0007] Further, in the case of inputting a single optical signal, after the arrangement of the phase change material units is completed according to the two-dimensional intensity distribution diagram of the multi-mode interference region generated by the input single optical signal, the crystal form of the arranged phase change material units is switched, different optical field distribution forms of the single optical signal in the multi-mode interference region are obtained, the optical signal output positions under different optical field distribution forms are connected with the output waveguide, and one output waveguide is connected with only one optical signal output position.

[0008] Further, one end of the multimode interference region can be connected with M input waveguides side by side, and the input of the optical signal is controlled to be input into the multimode interference region from only one input waveguide port at the same time, the two-dimensional intensity distribution diagram of the optical field under different input positions is obtained through simulation, and then the arrangement region of the phase change material unit under different input positions is determined according to different two-dimensional intensity distribution diagrams of the optical field.

[0009] Further, the optical signal is controlled to enter the multimode interference region from the Mth input waveguide, the arrangement of the phase change material unit under the Mth input position is completed according to the two-dimensional intensity distribution diagram of the optical field under the Mth input position, the crystal form of the phase change material unit on the arrangement region of the phase change material unit under the Mth input position is switched, different optical field distribution forms under the Mth input position are obtained, the connection between the optical signal output position and the output waveguide of different optical field distribution forms under the Mth input position is established, and one output waveguide is connected with one optical signal output position.

[0010] Further, in the two-dimensional intensity distribution diagram corresponding to each input waveguide position, 2-3 light intensity maximum points with the maximum light intensity are selected as the center points of the phase change material units.

[0011] Further, the input waveguide and the output waveguide adopt a trapezoidal taper structure, and the wider end of the taper waveguide is connected with the multimode interference region.

[0012] Further, the waveguide core layer material of the multimode interference region is selected from one of Si, silicon nitride, silicon dioxide, indium phosphide and polymer.

[0013] Further, when the selected phase change material is switched between the amorphous state and the crystalline state, the refractive index difference Δn = 1-2.

[0014] Further, the phase change material is selected from GST, Sb2Se3, VO2 or Sb-Te alloy.

[0015] Further, the shape of the phase change material unit can be strip-shaped or dot-shaped.

[0016] Compared with the prior art, the beneficial effects of the present application are as follows: 1. By means of the significant difference in the refractive index of the phase change material, the arrangement of the phase change material is performed according to the optical field distribution of the optical signal in the multimode interference region, so as to achieve the purpose of regulating the optical field distribution in the multimode interference region. Through the combination of the states of the phase change material at different positions, the change of the transmission path of the optical signal in the multimode interference region can be realized, the full-logic output of the optical signal between multiple output ports can be realized, and thus the optical switch matrix expansion of the optical signal 1xN is realized.

[0017] 2. By connecting multiple light input ports, arranging the corresponding phase change material according to the light field distribution of each input port, and then regulating the phase change material arranged on the light field corresponding to each input port, the full logic output between the multiple output ports corresponding to each input port can be obtained through the combination of the state of the phase change material, so as to further realize the expansion of the optical switch matrix from MxN. With the help of the crystal form control of the phase change material unit, the full logic mapping is realized through the different combination states of the phase change material unit, and the flexibility and programmability of the logic control are improved.

[0018] 3. The phase change material can maintain the state after phase change without maintaining energy, and the multi-mode interference area of the optical switch is regulated by using the phase change material, so that the power consumption can be significantly reduced, and the optical path configuration is suitable for long-term stability. At the same time, the phase change process is completed in nanoseconds to microseconds, which is two orders of magnitude faster than the thermal light effect, and can better meet the demand of high-speed optical communication and calculation.

[0019] 4. The optical switch designed in the application supports 1xN or MxN optical switch matrix, without connecting or connecting multiple basic units in series or in parallel, and by increasing the number of phase change material unit arrangements of the multi-mode interference area, the multi-port output and multi-mode output of the optical switch can be realized, which is conducive to the realization of high integration of integrated circuits, and also provides a basis for subsequent large-scale expansion. The optical switch designed in the application only makes adjustment in structure, and the preparation process can still refer to the process of the original integrated photon platform, which has good process compatibility compared with the existing process. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. In all the drawings, similar elements or parts are generally identified by similar reference signs. In the drawings, each element or part is not necessarily drawn according to the actual proportion. Obviously, the drawings described below are some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without paying creative labor.

[0021] Figure 1 is the 1x4 type optical switch structure designed in the application.

[0022] Figure 2 is the light field distribution and transmission path of the optical signal in the multi-mode interference area without introducing the phase change material.

[0023] Figure 3 is the different optical signal transmission paths obtained by regulating the state of the phase change material after introducing the phase change material.

[0024] Figure 4is the comparison of optical field distribution when taper waveguide and straight waveguide are used as input waveguide.

[0025] Figure 5 is a multi-port optical switch structure based on phase change material and non-volatile regulation.

[0026] The reference signs are as follows: 101-input waveguide, 102-multimode interference region, 103-phase change material unit, 104-output waveguide. DETAILED DESCRIPTION

[0027] The embodiments of the technical scheme of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs; the terms used herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0028] Herein, the suffix such as "module", "part", or "unit" used to represent an element is only for the convenience of description of the present application, and has no specific meaning by itself. Therefore, "module", "part", or "unit" can be mixedly used.

[0029] In the present specification, certain embodiments can be disclosed in a format that is a range. It should be understood that this "in a range" description is only for the convenience and brevity, and should not be interpreted as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered to have specifically disclosed all possible sub-ranges and individual numerical values within the range. For example, the description of the range "1-6" should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6. The above rule applies regardless of the breadth of the range.

[0030] The present embodiment takes silicon nitride as an example of the base of the multimode interference region, and describes how the present application realizes the structure of 1x4 optical switch and its working principle. Referring to the structure of the 1x4 optical switch of the present embodiment, the structure of MxN optical switch can also be obtained by analogy.

[0031] The arrangement structure and position of Sb2Se3 phase change material in the 1x4 optical switch are as follows Figure 1The left upper corner of the multi-mode interference region is connected with an input waveguide, the size of the multi-mode interference region is 240 μm x 12.5 μm, and the right side of the multi-mode interference region is connected with four output waveguides in parallel. The input waveguide and the output waveguide both adopt a ladder-shaped taper structure, the wider end of the taper waveguide is connected with the multi-mode interference region, which is used to realize mode size transition and light field matching, so as to reduce the insertion loss and improve the coupling efficiency. The length of the taper waveguide is about 15 μm, the width of the narrower end is 800 nm, and the thickness of the taper waveguide is 800 nm. In addition, the waveguide material of the multi-mode interference region is Si3N4, the refractive index of which is 2.0; the cladding material is SiO2, the refractive index of which is 1.45; and the working wavelength of the optical signal is 1550 nm.

[0032] According to the above size parameters, a structure model of the multi-mode interference region is established by using the finite difference time domain method or the eigenmode expansion method, and a two-dimensional intensity distribution diagram of the light field in the multi-mode interference region is obtained by simulation. In the case where no phase change material is introduced, the light field simulation of the optical signal in the multi-mode interference region is as shown in Figure 2 .

[0033] As can be seen from Figure 2 , when the input light enters the multi-mode interference (MMI) region from the input waveguide, a plurality of transverse modes will be excited, and each mode will interfere with each other during propagation, forming a periodic light field intensity distribution, i.e. a self-imaging effect, which determines the energy distribution and coherent recurrence position of the light field in the MMI. The light field presents a plurality of energy gathering points in the propagation direction. At each energy gathering point, the input light field is locally reproduced in space, and the light intensity reaches a maximum value.

[0034] According to the light intensity distribution shown in Figure 2 , the coordinates of the local maximum points of the light field intensity in the MMI region can be recorded and obtained. According to the order from large to small of the light field intensity, the center coordinates (n-x i , n-y i ) of n light intensity maximum points can be extracted, wherein n represents the nth point, and the light intensity of the nth point is arranged in the nth position according to the order from large to small of the light field intensity of each local maximum point extracted in the MMI region; x i is the longitudinal coordinate of the nth point in the multi-mode interference region along the propagation direction, and y i is the transverse offset of the nth point in the multi-mode interference region. In order to realize a 1x4 optical switch, the first two light intensity maximum points with the strongest light intensity are selected, and the center coordinates of the two light intensity maximum points are (1-x1, 1-y1) and (2-x2, 2-y2) respectively, which are approximately shown in Figure 2 .

[0035] Based on the coordinates (1-x1, 1-y1) and (2-x2, 2-y2) in the MMI region, these coordinates are used as the center coordinates of the two phase change material elements. Two phase change material elements are then arranged on the waveguide in the multimode interference region. The resulting arrangement of the two phase change material elements is as follows: Figure 1 The white and black horizontal stripes in the middle.

[0036] Figure 1 In the model, both phase change material units have dimensions of 15 μm in length, 2.3 μm in width, and 50 nm in thickness, and the phase change material used is Sb₂Se₃. Based on the coordinate positions of (1-x₁, 1-y₁) and (2-x₂, 2-y₂) in the MMI region, the... Figure 1 The center of the phase change material unit in the white horizontal bar is approximately 130 μm from the MMI input, located at the bottom of the MMI region; determine Figure 1 The center of the phase change material unit in the black horizontal bar is about 150 μm from the MMI input terminal, and the center of the phase change material is about 7.45 μm from the bottom of the MMI. Figure 2 The center coordinates of the first intensity maximum point are (1-x1, 1-y1) and Figure 1 Compared to the center coordinates of the phase change material unit represented by the white horizontal bars, the offset distance in the lateral and longitudinal directions is controlled within ±0.5 μm. Figure 2 The center coordinates of the second maximum light intensity point are (2-x2, 2-y2) and Figure 1 Compared to the center coordinates of the phase change material unit represented by the black horizontal bars, the offset distance in the horizontal and vertical directions is controlled within ±0.5 μm.

[0037] Through the above structural design, especially the placement of the phase change materials in the multimode interference region and the requirements they meet, the two phase change material units are arranged differently in the longitudinal and transverse directions, thereby generating local refractive index perturbations within the MMI region. This effectively alters the propagation path and optical field energy distribution of the multimode interference. Therefore, when the two phase change material units form combinations with different phase change morphologies, controllable selection of the optical signal between different output ports can be achieved, thus realizing the function of a multi-port optical switch. For example... Figure 3 As shown, by introducing phase change materials and controlling the phase change states of the two phase change material units, different optical signal transmission paths can be obtained.

[0038] like Figure 3-1When the left side phase change material is in a crystalline state and the right side phase change material is in an amorphous state, the left side crystalline phase change material has a higher refractive index, which increases the local propagation constant of the light field in this region, resulting in the interference field distribution being shifted upwards; at the same time, the right side phase change material remains in an amorphous state, and has a lower refractive index, which does not form a significant constraint on the central region. The difference between the two states before and after the original multimode interference process of the MMI changes the coherent superposition rule of the light field in the propagation process, causing the self-imaging position and energy distribution to shift. Finally, the light field is mainly concentrated at the upper right of the MMI (i.e., the position of the highlighted area of the first horizontal line on the right side of Figure 3-1 According to the changed light signal transmission path, an output waveguide out1 is connected at the changed light signal output position, realizing directional output of the light signal in this phase change material combination state and achieving a single-port output mode.

[0039] As Figure 3-2 When the left side phase change material is in an amorphous state and the right side phase change material is in a crystalline state, the difference in refractive index between the two causes the refractive index distribution in the MMI region to change, thereby breaking the original symmetric interference condition. Specifically, the left side amorphous phase change material has a weak disturbance on the light field, while the right side crystalline phase change material has a higher refractive index and introduces a significant phase delay effect in the central region of the MMI, causing the light field interference pattern to shift. This asymmetric distribution of refractive index causes the propagation path and energy distribution of the input light signal in the MMI region to be re-adjusted, ultimately causing most of the optical power to be directed to the output positions of the Figure 3-2 second and fourth horizontal lines on the right side (i.e., the positions of the highlighted areas of the second and fourth horizontal lines on the right side of Figure 3-2 According to the changed light signal transmission path, output waveguides out2 and out4 are connected at the changed light signal output positions, respectively, which can realize directional output of the light signal in this phase change material combination state and achieve a dual-port output mode.

[0040] Similarly, by controlling the two phase change material units to form other types of phase change combination states (for example, both in a crystalline state or both in an amorphous state), according to the simulation results, the light signal can form an energy concentration point at the Figure 3-2 third horizontal line on the right side. Connecting an output waveguide out3 at this output position can realize output of the light signal at the out3 port.

[0041] On this basis, further increasing the number of phase change material units or enriching their phase change combination states can form more energy concentration points in the multimode interference region, realize more flexible output port configurations, and thus construct a 1xN type multi-port optical switch matrix.

[0042] In addition, the light field distribution comparison when using a taper waveguide and a straight waveguide as an input end waveguide is as follows:Figure 4 As shown in FIG. 1, the light field distribution of the light signal in the multi-mode interference region is shown. As shown in FIG. 1, the light field distribution of the light signal in the multi-mode interference region is shown. Figure 4 As shown in FIG. 1, the light field distribution of the light signal in the multi-mode interference region is shown. As shown in FIG. 1, the light field distribution of the light signal in the multi-mode interference region is shown.

[0043] On the basis of the present embodiment, by further increasing the number of arrangements of the phase change material units, more phase change material combination states can be formed, and more directional output modes of the light signal can be formed, thereby realizing a 1xN optical switch matrix of an optical switch. For example, the present embodiment arranges 2 phase change material units, which can form 4 phase change combination states. If 3 phase change material units are arranged, 8 phase change combination states can be increased. By changing the 8 phase change combination states, compared with the 4 phase change combination states, more directional output modes of the light signal can be formed, and the number of output ends of the optical switch can be increased.

[0044] On the basis of the present embodiment, by changing the input position of the waveguide input end, the two-dimensional intensity distribution of the light field in the multi-mode interference region under other input positions can be obtained through simulation by establishing the multi-mode interference region structure model. According to the two-dimensional intensity distribution of the light field in the multi-mode interference region under different input positions, referring to the arrangement mode and method of the phase change material units of the present example, the crystal form of the phase change material units arranged in the arrangement region of the phase change material units under the corresponding input position is switched, the directional output channels of the light signal under this input position can be determined, thereby realizing the output mode and the specific position of the output end of the light signal under this input position. After arranging the output end signals under each input end position, a plurality of input waveguides are connected at the input end of the multi-mode interference region, thereby realizing a MxN optical switch matrix of an optical switch.

[0045] Figure 5The structure is based on phase change material and non-volatile regulation multi-port optical switch. In the figure, 101 is an input waveguide, which can be set as M input waveguides connected in parallel; 102 is a multimode interference region; 103 is a phase change material unit; and 104 is an output waveguide. According to the position of each input waveguide, the corresponding light field two-dimensional intensity distribution in the multimode interference region is obtained. Then, according to the two-dimensional intensity distribution, the arrangement position of the corresponding phase change material unit is obtained by referring to the arrangement mode and method of the phase change material unit in the example, forming an m×n phase change material unit arrangement form. Then, by adjusting the crystal form of the phase change material unit on the phase change material unit arrangement region under the corresponding input position, different types of optical signal directional output channels under the input position can be obtained. Finally, according to the directional output channel of the optical signal, the connection position of the input waveguide is confirmed, N output waveguides connected in parallel are obtained, and then an M×N optical switch matrix of an optical port switch is formed.

[0046] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A multi-port optical switch based on phase change material and non-volatile regulation, comprising an input waveguide, a multi-mode interference region and an output waveguide, the multi-mode interference region being located between the input waveguide and the output waveguide; after an optical signal is input from a port of the input waveguide, the optical signal enters the multi-mode interference region, and after signal modulation of the multi-mode interference region, the optical signal is output from a port of the output waveguide; the structure of the multi-mode interference region from bottom to top is in turn a substrate, a substrate, a waveguide on the substrate and a phase change material unit, the phase change material unit is arranged on the waveguide of the multi-mode interference region, the length of the phase change material unit is 5-20 μm, the width of the phase change material unit is 0.5-2.5 μm, and the thickness of the phase change material unit is 20-50 nm, and the arrangement position of the phase change material unit is arranged according to the following steps and methods: A. A structural model of the multi-mode interference region is established, a two-dimensional intensity distribution diagram of an optical field in the multi-mode interference region is obtained by simulation, and according to the intensity, an energy concentration point in the propagation direction of the optical field in the multi-mode interference region is extracted, and one energy concentration point corresponds to one optical intensity maximum point; B. According to the requirement of intensity from large to small, the center coordinates (n-x i , n-y i ) of n light intensity maximum points are extracted, wherein n represents the nth light intensity maximum point extracted, the light intensity of the nth light intensity maximum point is arranged in the order from large to small according to the light intensity of each energy gathering point extracted in the two-dimensional intensity distribution diagram; x i is the longitudinal coordinate of the nth light intensity maximum point in the propagation direction of the multimode interference region, and y i is the transverse offset of the nth light intensity maximum point in the multimode interference region. C、select the first n light intensity maximum points as the center points of the arrangement of the phase change material units, the center point coordinates of the nth phase change material unit are the center coordinates of the selected nth light intensity maximum point (n-x i , n-y i ), and the phase change material units are arranged on the waveguide of the multimode interference region according to the center point coordinates of the phase change material units.

2. A multi-port optical switch based on phase change material and non-volatile control as claimed in claim 1, wherein, The center point coordinate of the nth phase change material unit in step C is compared with the coordinate (n-x i , n-y i ) of the nth light intensity maximum point, and the lateral and longitudinal offset distances are both controlled within ±0.5 μm.

3. A multiport optical switch based on phase change material and nonvolatile control according to claim 1 or 2, characterized in that, After the arrangement of the phase change material unit is completed according to the two-dimensional intensity distribution diagram of the multi-mode interference region generated by the input of a single optical signal, the crystal form of the arranged phase change material unit is switched, different optical field distribution forms of the single optical signal in the multi-mode interference region are obtained, the optical signal output positions under different optical field distribution forms are connected with the output waveguide, and one output waveguide is connected with only one optical signal output position.

4. A multi-port optical switch based on phase change material and non-volatile control as claimed in claim 3, wherein, One end of the multi-mode interference region can be connected with M input waveguides side by side, the input of the optical signal is controlled to be able to enter the multi-mode interference region from only one input waveguide port at the same time, a two-dimensional intensity distribution diagram of an optical field under different input positions is obtained by simulation, and then the arrangement region of the phase change material unit under different input positions is determined according to different two-dimensional intensity distribution diagrams of the optical field.

5. A multiport optical switch based on phase change material and nonvolatile control as claimed in claim 4, wherein, The optical signal is controlled to enter the multi-mode interference region from the Mth input waveguide, the arrangement of the phase change material unit under the Mth input position is completed according to the two-dimensional intensity distribution diagram of the optical field under the Mth input position, the crystal form of the phase change material unit in the arrangement region of the phase change material unit under the Mth input position is switched, different optical field distribution forms under the Mth input position are obtained, the connection between the optical signal output positions under different optical field distribution forms under the Mth input position and the output waveguide is established, and one output waveguide is connected with only one optical signal output position.

6. A multiport optical switch based on phase change material and nonvolatile control according to claim 4 or 5, characterized in that, The two-dimensional intensity distribution diagram corresponding to each input waveguide position selects 2-3 optical intensity maximum points with the maximum optical intensity as the center points of the phase change material unit.

7. A multiport optical switch based on phase change material and nonvolatile control as claimed in claim 1, 2, 4 or 5, wherein, The input waveguide and the output waveguide adopt a trapezoidal taper structure, and the wider end of the taper waveguide is connected with the multi-mode interference region.

8. A multiport optical switch based on phase change material and nonvolatile control as claimed in claim 1, 2, 4 or 5, wherein, The selected phase change material has a refractive index difference Δn = 1-2 when switching between amorphous state and crystalline state.

9. A multiport optical switch based on phase change material and nonvolatile control as claimed in claim 1, 2, 4 or 5, wherein, The phase change material is selected from GST, Sb2Se3, VO2 or Sb-Te alloy.

10. A multiport optical switch based on phase change material and nonvolatile control as claimed in claim 1, 2, 4 or 5, wherein, The shape of the phase change material unit can be strip-shaped or dot-shaped.

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