Multimode optical routing state switching unit and multimode optical switch

Abstract

The present disclosure provides a multimode optical routing state switching unit, comprising: a multimode input optical waveguide module comprising a first multimode input optical waveguide and a second multimode input optical waveguide, a multimode waveguide cross structure comprising a first optical path and a second optical path intersecting each other, a multimode output optical waveguide module comprising a first multimode output optical waveguide and a second multimode output optical waveguide, a multimode micro-ring optical modulation structure module comprising a multimode phase shifter and a multimode micro-ring resonator, the multimode phase shifter comprising a light guiding structure and a refractive index regulating structure, the refractive index regulating structure being configured to change the refractive index of the light guiding structure, the resonant wavelength of the multimode micro-ring resonator being related to the refractive index of the light guiding structure, and the multimode micro-ring resonator being configured to couple a first multimode optical signal to the other end of the first optical path or the other end of the second optical path in response to a change in the resonant wavelength, and to couple a second multimode optical signal to the other end of the first optical path or the other end of the second optical path.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technology, and more specifically, to a multi-mode optical routing state switching unit and a multi-mode optical switch. Background Art

[0002] Optical interconnect has the advantages of high bandwidth, low latency, and strong anti-interference, and has important applications in short-distance communications such as high-performance computers and data centers. The introduction of Mode Division Multiplexing (MDM) technology provides a solution for improving the communication capacity of on-chip optical interconnects.

[0003] At present, in order to make the on-chip optical interconnection system using MDM technology more flexible, a multi-mode optical switch that can complete optical signal exchange is indispensable. Traditional optical switch arrays often only support a single mode and cannot be directly expanded to a multi-mode network. Existing multi-mode optical switches mostly use a demultiplexing-switching-multiplexing method, that is, the multi-mode optical signal to be processed is demultiplexed into a single-mode optical signal, which is then multiplexed into a multi-mode optical signal after being exchanged using a single-mode optical switch. However, the above scheme increases the complexity of the on-chip optical communication network, and there are problems such as large device size, high loss, and difficulty in adjustment and control. Summary of the invention

[0004] In order to solve at least one of the above-mentioned and other technical problems in the prior art, the present disclosure provides a multi-mode optical routing state switching unit and a multi-mode optical switch. Since the resonant wavelength of the multi-mode microring resonator is related to the refractive index of the light-guiding structure of the multi-mode phase shifter, the refractive index control structure of the multi-mode phase shifter is constructed to change the refractive index of the light-guiding structure, so that the multi-mode microring resonator couples the first multi-mode optical signal to the other end of the first optical path or the other end of the second optical path in response to the change of the resonant wavelength, and couples the second multi-mode optical signal to the other end of the first optical path or the other end of the second optical path, thereby realizing simultaneous control of optical signals of multiple modes.

[0005] The embodiment of the present disclosure provides a multimode optical routing state switching unit, comprising: a multimode input optical waveguide module, comprising: a first multimode input optical waveguide, used to input a first multimode optical signal to be processed; a second multimode input optical waveguide, used to input a second multimode optical signal to be processed; a multimode waveguide cross structure, comprising a first optical path and a second optical path intersecting each other, one end of the first optical path being connected to the first multimode input optical waveguide, and one end of the second optical path being connected to the second multimode input optical waveguide; a multimode output optical waveguide module, comprising: a first multimode output optical waveguide, connected to the other end of the second optical path , and a second multi-mode output optical waveguide, connected to the other end of the above-mentioned first optical path; a multi-mode micro-ring optical modulation structure module, including: a multi-mode phase shifter, including: a light guide structure, and a refractive index control structure, which is configured to change the refractive index of the above-mentioned light guide structure; a multi-mode micro-ring resonator, the resonant wavelength is related to the refractive index of the above-mentioned light guide structure, and the above-mentioned multi-mode micro-ring resonator is configured to couple the above-mentioned first multi-mode optical signal to the other end of the above-mentioned first optical path or the other end of the above-mentioned second optical path in response to the change of the resonant wavelength, and couple the above-mentioned second multi-mode optical signal to the other end of the above-mentioned first optical path or the other end of the above-mentioned second optical path.

[0006] According to some embodiments of the present disclosure, the refractive index regulating structure changes the refractive index of the light guiding structure by using thermo-optical effect and electro-optical effect.

[0007] According to some embodiments of the present disclosure, the multimode waveguide cross structure further includes a first port, a second port, a third port and a fourth port, wherein the first port is connected to the first multimode input optical waveguide, the third port is connected to the second multimode input optical waveguide, the second port is connected to the first multimode output optical waveguide, and the fourth port is connected to the second multimode output optical waveguide, wherein the first port and the fourth port are respectively connected to the two ends of the first optical path, and the second port and the third port are respectively connected to the two ends of the second optical path.

[0008] According to some embodiments of the present disclosure, the multi-mode micro-ring optical modulation structure module includes a first multi-mode micro-ring optical modulation structure and a second multi-mode micro-ring optical modulation structure, the first multi-mode micro-ring optical modulation structure is arranged between the first port and the second port, the second multi-mode micro-ring optical modulation structure is arranged between the third port and the fourth port, the multi-mode phase shifter is arranged at a place away from the intersection of the first optical path and the second optical path, and the spacing between the first port and the first multi-mode micro-ring optical modulation structure, the spacing between the second port and the first multi-mode micro-ring optical modulation structure, the spacing between the third port and the second multi-mode micro-ring optical modulation structure, and the spacing between the fourth port and the second multi-mode micro-ring optical modulation structure are all the same.

[0009] According to some embodiments of the present disclosure, the first multimode micro-ring optical modulation structure is arranged between the first multimode input optical waveguide and the first multimode output optical waveguide, the second multimode micro-ring optical modulation structure is arranged between the second multimode input optical waveguide and the second multimode output optical waveguide, the multimode phase shifter is arranged at the intersection away from the first optical path and the second optical path, and the spacing between the first multimode input optical waveguide and the first multimode micro-ring optical modulation structure, the spacing between the first multimode output optical waveguide and the first multimode micro-ring optical modulation structure, the spacing between the second multimode input optical waveguide and the second multimode micro-ring optical modulation structure, and the spacing between the second multimode output optical waveguide and the second multimode micro-ring optical modulation structure are all the same.

[0010] According to some embodiments of the present disclosure, the waveguide heights of the multimode microring resonators of the first multimode microring optical modulation structure and the second multimode microring optical modulation structure are the same; the radius of the multimode microring resonator of the first multimode microring optical modulation structure is smaller than the radius of the multimode microring resonator of the second multimode microring optical modulation structure; the waveguide width of the multimode microring resonator of the first multimode microring optical modulation structure is larger than the waveguide width of the multimode microring resonator of the second multimode microring optical modulation structure.

[0011] According to some embodiments of the present disclosure, the first port, the second port, the third port, and the fourth port have the same propagation constant as the multimode microring resonator, and the waveguide widths of the first port, the second port, the third port, and the fourth port are between the waveguide width of the multimode microring resonator of the first multimode microring optical modulation structure and the waveguide width of the multimode microring resonator of the second multimode microring optical modulation structure.

[0012] According to some embodiments of the present disclosure, a multimode waveguide bending structure is respectively arranged between the multimode waveguide crossing structure and the first multimode input optical waveguide, the second multimode input optical waveguide, the first multimode output optical waveguide, and the second multimode output optical waveguide, and the multimode waveguide bending structure includes a first multimode straight waveguide, a multimode bent waveguide, and a second multimode straight waveguide connected in sequence.

[0013] According to some embodiments of the present disclosure, the first multimode input optical waveguide, the second multimode input optical waveguide, the first multimode straight waveguide and the second multimode straight waveguide have the same waveguide cross-sectional dimensions.

[0014] According to some embodiments of the present disclosure, a multi-mode optical switch includes any one of the multi-mode optical routing state switching units described above.

[0015] According to a multimode optical routing state switching unit and a multimode optical switch provided by the present disclosure, since the resonant wavelength of the multimode microring resonator is related to the refractive index of the light-guiding structure of the multimode phase shifter, the refractive index control structure of the multimode phase shifter is constructed to change the refractive index of the light-guiding structure, so that the multimode microring resonator couples the first multimode optical signal to the other end of the first optical path or the other end of the second optical path in response to the change in the resonant wavelength, and couples the second multimode optical signal to the other end of the first optical path or the other end of the second optical path, thereby realizing simultaneous control of optical signals of multiple modes. The above-mentioned multimode optical routing state switching unit is cascaded to form a multimode optical switch to achieve port expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural diagram of a multimode optical routing state switching unit according to an illustrative embodiment of the present disclosure;

[0017] Figure 2 yes Figure 1 A structural diagram of a portion of a multi-mode micro-ring optical modulation structural module of a multi-mode optical routing state switching unit of the exemplary embodiment shown;

[0018] Figure 3 yes Figure 2 A cross-sectional view of a multimode phase shifter of a multimode optical routing state switching unit of an exemplary embodiment shown;

[0019] Figure 4 yes Figure 2 A cross-sectional view of a multimode phase shifter of a multimode optical routing state switching unit of another exemplary embodiment shown;

[0020] Figure 5 yes Figure 2 A cross-sectional view of a multimode phase shifter of a multimode optical routing state switching unit of another exemplary embodiment is shown;

[0021] Figure 6 yes Figure 1 A structural diagram of a multimode waveguide cross structure of a multimode optical routing state switching unit of the exemplary embodiment shown;

[0022] Figure 7 is a principle diagram of a through state of a multimode optical routing state switching unit according to an exemplary embodiment of the present disclosure;

[0023] Figure 8 is a schematic diagram of a crossover state of a multimode optical routing state switching unit according to an exemplary embodiment of the present disclosure;

[0024] Fig. 9 is a schematic diagram of a through state of a multimode optical routing state switching unit according to another exemplary embodiment of the present disclosure;

[0025] Fig.10 is a schematic diagram of a crossover state of a multimode optical routing state switching unit according to another exemplary embodiment of the present disclosure;

[0026] Fig.11 is a schematic diagram of a multimode optical routing state switching unit according to an exemplary embodiment of the present disclosure;

[0027] Fig.12 yes Figure 1 A structural diagram of a multimode waveguide bending structure of a multimode optical routing state switching unit of the exemplary embodiment shown;

[0028] Fig.13 is a structural diagram of a multimode optical routing state switching unit according to another exemplary embodiment of the present disclosure;

[0029] Fig.14 is a schematic diagram of a multi-mode optical switch implemented based on a multi-mode optical routing state switching unit in an exemplary embodiment of the present disclosure;

[0030] In the drawings, the meanings of the reference numerals are as follows:

[0031] 11. Multimode input optical waveguide module;

[0032] 111. a first multimode input optical waveguide;

[0033] 112. a second multimode input optical waveguide;

[0034] 12. Multi-mode micro-ring optical modulation structure module;

[0035] 121. The first multi-mode micro-ring optical modulation structure;

[0036] 122. A second multi-mode micro-ring optical modulation structure;

[0037] 21. Multimode microring resonator;

[0038] 22. Multimode phase shifter;

[0039] 221. Extreme heat;

[0040] 222. Light guide structure;

[0041] 223, a first doped region;

[0042] 224. Electrode;

[0043] 225, a second doped region;

[0044] 226, a third doped region;

[0045] 227, fourth doping region;

[0046] 228, fifth doping region;

[0047] 13. Multimode waveguide cross structure;

[0048] 31. First port;

[0049] 32. Second port;

[0050] 33. The third port;

[0051] 34. Fourth port;

[0052] 14. Multimode waveguide bending structure;

[0053] 41. The first multimode straight waveguide;

[0054] 42. Multimode curved waveguide;

[0055] 43. Second multimode straight waveguide;

[0056] 15. Multimode output optical waveguide module;

[0057] 151. a first multimode output optical waveguide;

[0058] 152. a second multimode output optical waveguide;

[0059] A. Multimode waveguide coupling region. DETAILED DESCRIPTION

[0060] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0061] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0062] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0063] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0064] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0065] Figure 1 is a structural diagram of a multimode optical routing state switching unit according to an illustrative embodiment of the present disclosure.

[0066] According to the multimode optical routing state switching unit provided by the embodiment of the present disclosure, Figure 1 As shown, the multimode optical routing state switching unit includes a multimode input optical waveguide module 11, a multimode waveguide cross structure 13, a multimode output optical waveguide module 15 and a multimode micro-ring optical modulation structure module 12, wherein the multimode input optical waveguide module 11 includes a first multimode input optical waveguide 111 and a second multimode input optical waveguide 112, the first multimode input optical waveguide 111 is used to input a first multimode optical signal to be processed, and the second multimode input optical waveguide 112 is used to input a second multimode optical signal to be processed, the multimode waveguide cross structure 13 includes a first optical path and a second optical path intersecting each other, one end of the first optical path is connected to the first multimode input optical waveguide 111, and one end of the second optical path is connected to the second multimode input optical waveguide 112, and the multimode output optical waveguide module 15 includes a first multimode output An output optical waveguide 151 and a second multimode output optical waveguide 152, the first multimode output optical waveguide 151 is connected to the other end of the second optical path, the second multimode output optical waveguide 152 is connected to the other end of the first optical path, the multimode micro-ring optical modulation structure module 12 includes a multimode phase shifter 22 and a multimode micro-ring resonator 21, the multimode phase shifter 22 includes a light-guiding structure and a refractive index regulating structure, the refractive index regulating structure is configured to change the refractive index of the light-guiding structure, the resonant wavelength of the multimode micro-ring resonator 21 is related to the refractive index of the light-guiding structure, and the multimode micro-ring resonator 21 is configured to couple the first multi-mode optical signal to the other end of the first optical path or the other end of the second optical path in response to the change in the resonant wavelength, and couple the second multi-mode optical signal to the other end of the first optical path or the other end of the second optical path.

[0067] The multi-mode optical routing state switching unit provided according to the embodiment of the present disclosure can realize simultaneous regulation of optical signals of multiple modes. The multi-mode optical routing state switching unit is cascaded to form a multi-mode optical switch to realize port expansion.

[0068] According to the embodiments of the present disclosure, the multi-mode optical routing state switching unit may be implemented on a silicon-based chip, but is not limited thereto.

[0069] According to an embodiment of the present disclosure, the refractive index regulating structure changes the refractive index of the light guiding structure by using the thermo-optic effect and the electro-optic effect.

[0070] Figure 2 yes Figure 1 The structure diagram of a portion of the multi-mode micro-ring optical modulation structure module 12 of the multi-mode optical routing state switching unit of the exemplary embodiment shown, Figure 3 yes Figure 2 A cross-sectional view of a multi-mode phase shifter 22 of a multi-mode optical routing state switching unit according to an exemplary embodiment is shown.

[0071] like Figure 2 and Figure 3 As shown, the multi-mode micro-ring optical modulation structure module 12 includes a multi-mode phase shifter 22 and a multi-mode micro-ring resonator 21. The multi-mode phase shifter 22 includes a light guide structure 222 and a refractive index control structure. Figure 3 As shown, the hot electrode 221 is located directly above the light guide structure 222. The refractive index control structure is the hot electrode 221. The hot electrode 221 can be made of a resistive material such as titanium nitride (TiN) or metal tungsten. The hot electrode 221 uses the thermo-optic effect to change the refractive index of the light guide structure 222. The thermo-optic effect refers to the change of the refractive index of a material with temperature. Taking silicon material as an example, silicon material has a positive thermo-optic coefficient, and the refractive index increases with increasing temperature. By making the hot electrode 221 above the light guide structure 222, the temperature of the light guide structure 222 is changed, thereby changing the refractive index of the light guide structure 222.

[0072] Figure 4 yes Figure 2 A cross-sectional view of a multi-mode phase shifter of a multi-mode optical routing state switching unit according to another exemplary embodiment is shown.

[0073] like Figure 4 As shown, the refractive index control structure is a combination of an electrode 224 and a first doped region 223. The first doped regions 223 on both sides of the light-guiding structure 222 are subjected to the same P-type doping or the same N-type doping. By making the first doped regions 223 on both sides of the light-guiding structure 222 to form resistors, the Joule heat generated by the resistors under different bias voltages is used to change the temperature of the light-guiding structure 222, thereby changing the refractive index of the light-guiding structure 222.

[0074] Figure 5 yes Figure 2 A cross-sectional view of a multi-mode phase shifter of a multi-mode optical routing state switching unit according to yet another exemplary embodiment is shown.

[0075] like Figure 5 As shown, the refractive index control structure is a combination of an electrode 224, a second doping region 225, a third doping region 226, a fourth doping region 227 and a fifth doping region 228. Taking silicon material as an example, the electro-optic effect refers to the phenomenon that the refractive index (or absorption coefficient) of the material changes with an external electric field. Since silicon material does not have a linear electro-optic effect, the plasma dispersion effect of silicon is usually used, and the refractive index of the silicon material decreases with the increase of the carrier concentration. By adopting different doping forms to form a PN junction, the second doping region 225 can be selected as P-type doping, the third doping region 226 can be selected as N-type doping, and a voltage is applied to extract or inject carriers in the light guide structure 222, thereby changing the refractive index of the light guide structure 222. At the same time, in order to form an ohmic contact, the fourth doping region 227 can be selected as P-type heavily doped, the fifth doping region 228 can be selected as N-type heavily doped, and the electrode 224 can be selected as a low resistivity material such as aluminum.

[0076] Figure 6 yes Figure 1 The structure diagram of the multi-mode waveguide crossing structure of the multi-mode optical routing state switching unit of the exemplary embodiment is shown.

[0077] According to the embodiments of the present disclosure, Figure 6 As shown, the multimode waveguide cross structure 13 also includes a first port 31, a second port 32, a third port 33 and a fourth port 34, the first port 31 is connected to the first multimode input optical waveguide 111, the third port 33 is connected to the second multimode input optical waveguide 112, the second port 32 is connected to the first multimode output optical waveguide 151, and the fourth port 34 is connected to the second multimode output optical waveguide 152, wherein the first port 31 and the fourth port 34 are respectively connected to the two ends of the first optical path, and the second port 32 and the third port 33 are respectively connected to the two ends of the second optical path.

[0078] According to an embodiment of the present disclosure, the ends of the intersecting first optical path and second optical path of the multimode waveguide intersection structure 13, i.e., the connection between the first port 31 and the fourth port 34 and the first optical path, and the connection between the second port 32 and the third port 33 and the second optical path, are tapered structures.

[0079] According to an embodiment of the present disclosure, the multimode waveguide crossing structure 13 may adopt a multimode interference coupler structure or a sub-wavelength grating-based waveguide crossing structure.

[0080] According to the embodiments of the present disclosure, Figure 1As shown, the multimode micro-ring optical modulation structure module 12 includes a first multimode micro-ring optical modulation structure 121 and a second multimode micro-ring optical modulation structure 122. The first multimode micro-ring optical modulation structure 121 is arranged between the first port 31 and the second port 32, and the second multimode micro-ring optical modulation structure 122 is arranged between the third port 33 and the fourth port 34. The multimode phase shifter 22 is arranged at a place far away from the intersection of the first optical path and the second optical path. The spacing between the first port 31 and the first multimode micro-ring optical modulation structure 121, the spacing between the second port 32 and the first multimode micro-ring optical modulation structure 121, the spacing between the third port 33 and the second multimode micro-ring optical modulation structure 122, and the spacing between the fourth port 34 and the second multimode micro-ring optical modulation structure 122 are all the same.

[0081] According to an embodiment of the present disclosure, the first port 31, the second port 32, the third port 33, and the fourth port 34 have the same propagation constant as the multimode microring resonator 21, and the waveguide widths of the first port 31, the second port 32, the third port 33, and the fourth port 34 are between the waveguide width of the multimode microring resonator 21 of the first multimode microring optical modulation structure 121 and the waveguide width of the multimode microring resonator 21 of the second multimode microring optical modulation structure 122.

[0082] According to the embodiment of the present disclosure, the first port 31, the second port 32, the third port 33, the fourth port 34 and the multi-mode microring resonator 21 have the same propagation constant to meet the phase matching condition, and the conversion between different modes of the optical signal can be achieved.

[0083] According to an embodiment of the present disclosure, the waveguide heights of the multimode microring resonators 21 of the first multimode microring optical modulation structure 121 and the second multimode microring optical modulation structure 122 are the same, the radius of the multimode microring resonator 21 of the first multimode microring optical modulation structure 121 is smaller than the radius of the multimode microring resonator 21 of the second multimode microring optical modulation structure 122, and the waveguide width of the multimode microring resonator 21 of the first multimode microring optical modulation structure 121 is larger than the waveguide width of the multimode microring resonator 21 of the second multimode microring optical modulation structure 122.

[0084] Figure 7 It is a principle diagram of a through state of a multi-mode optical routing state switching unit according to an illustrative embodiment of the present disclosure.

[0085] According to the embodiments of the present disclosure, Figure 7As shown, the two routing states are the through state and the cross state. Taking the simultaneous regulation of the optical signals of TE0 (fundamental mode) and TE1 (first-order mode) as an example, taking the first multimode optical signal to be processed input by the first multimode input optical waveguide 111 as an example, when its wavelength is λ0, TE0 mode, if the refractive index is regulated at this time, the resonant wavelength of the first multimode micro-ring optical modulation structure 121 is λ0, that is, the resonance condition is met, the first multimode optical signal will be coupled to the first multimode micro-ring optical modulation structure 121 at the first port 31, and at the same time Since the TE0 mode in the first port 31 and the TE1 mode in the first multimode micro-ring optical modulation structure 121 meet the phase matching condition, and the phase matching condition is that the propagation constants of two waveguides with different widths are equal, the first multimode optical signal is converted from the TE0 mode to the TE1 mode and transmitted in the first multimode micro-ring optical modulation structure 121, and then coupled from the first multimode micro-ring optical modulation structure 121 to the second port 32, and at the same time converted from the TE1 mode to the TE0 mode, and output from the first multimode output optical waveguide 151, showing a straight-through state.

[0086] Figure 8 It is a principle diagram of a crossover state of a multimode optical routing state switching unit according to an illustrative embodiment of the present disclosure.

[0087] According to the embodiments of the present disclosure, Figure 8 As shown, when the wavelength of the first multimode optical signal is λ0, TE0 mode, the resonant wavelength of the first multimode micro-ring optical modulation structure 121 is not equal to λ0, that is, the resonance condition is not satisfied. At the first port 31, the first multimode optical signal interferes and cancels with the optical signal newly coupled into the first multimode micro-ring optical modulation structure 121 after circling the first multimode micro-ring optical modulation structure 121 for one cycle. Only a very small part of the first multimode optical signal is coupled into the first multimode micro-ring optical modulation structure 121 from the first port 31, which is manifested as the first multimode optical signal TE0 mode directly passing through the first optical path. Since the TE0 mode in the first optical path and the TE0 and TE1 modes in the second multimode micro-ring optical modulation structure 122 do not satisfy the phase matching condition, no coupling occurs at the fourth port 34, so it is output from the second multimode output optical waveguide 152, which is manifested as a cross state.

[0088] Fig. 9 It is a principle diagram of a through state of a multimode optical routing state switching unit according to another exemplary embodiment of the present disclosure.

[0089] According to the embodiments of the present disclosure, Fig. 9As shown, when the wavelength of the first multimode optical signal is λ0 and the TE1 mode, if the resonant wavelength of the second multimode micro-ring optical modulation structure 122 is λ0 by adjusting the refractive index at this time, that is, the resonance condition is met, since the TE1 mode in the first port 31 and the TE0 and TE1 modes in the first multimode micro-ring optical modulation structure 121 do not meet the phase matching condition, no coupling will occur at the first port 31, and the first multimode optical signal will directly pass through the first optical path and be coupled to the second multimode micro-ring optical modulation structure 122 at the fourth port 34. At the same time, since the TE1 mode in the fourth port 34 and the TE0 mode in the second multimode micro-ring optical modulation structure 122 meet the phase matching condition, the first multimode optical signal is converted from the TE1 mode to the TE0 mode and transmitted in the second multimode micro-ring optical modulation structure 122, and then coupled from the second multimode micro-ring optical modulation structure 122 to the third port 33, and at the same time converted from the TE0 mode to the TE1 mode, and then output from the first multimode output optical waveguide 151 through the second optical path, showing a straight-through state.

[0090] Fig.10 is a schematic diagram of a crossover state of a multimode optical routing state switching unit according to another exemplary embodiment of the present disclosure.

[0091] According to the embodiments of the present disclosure, Fig.10 As shown, when the wavelength of the first multimode optical signal is λ0 and TE1 mode, the resonant wavelength of the second multimode micro-ring optical modulation structure 122 is not equal to λ0, that is, the resonance condition is not met. When the first multimode optical signal is transmitted from the first port 31 to the fourth port 34 via the first optical path, the first multimode optical signal interferes and destructively with the optical signal newly coupled into the second multimode micro-ring optical modulation structure 122 after circling around the second multimode micro-ring optical modulation structure 122. It is manifested that the first multimode optical signal TE1 mode directly passes through the first optical path, so it is output from the second multimode output optical waveguide 152, showing a cross state.

[0092] The multi-mode optical routing state switching unit provided according to the embodiment of the present disclosure can realize the simultaneous regulation of optical signals of multiple modes. By simultaneously regulating the first multi-mode micro-ring optical modulation structure 121 and the second multi-mode micro-ring optical modulation structure 122, the simultaneous control of two mode routing states (i.e., the through state and the cross state) can be realized.

[0093] Fig.11 is a schematic diagram of a multi-mode optical routing state switching unit according to an illustrative embodiment of the present disclosure.

[0094] According to the embodiments of the present disclosure, Figure 6 and Fig.11As shown, by selecting the ends of the first optical path and the second optical path, i.e., the width of the tapered structure, and the length and width of the first optical path and the second optical path, the self-image positions of different modes are overlapped, and the intersection in the multimode waveguide coupling region A is placed at the self-image position, thereby achieving smaller loss and crosstalk. Optionally, the multimode waveguide coupling region A can be implemented using a subwavelength grating structure or a reverse design method. The subwavelength grating is composed of a grating medium (high refractive index material) and air (ground refractive material) medium. The reverse design method is a method that uses the intersection of computers and silicon photonics, and refers to a method that uses the expected results as the goal, relies on intelligent algorithms and model training, and reversely solves the device structure.

[0095] Fig.12 yes Figure 1 The structure diagram of the multi-mode waveguide bending structure 14 of the multi-mode optical routing state switching unit of the exemplary embodiment is shown.

[0096] According to an embodiment of the present disclosure, a multimode waveguide bending structure 14 is respectively arranged between the multimode waveguide cross structure 13 and the first multimode input optical waveguide 111, the second multimode input optical waveguide 112, the first multimode output optical waveguide 151, and the second multimode output optical waveguide 152. The multimode waveguide bending structure 14 includes a first multimode straight waveguide 41, a multimode bent waveguide 42, and a second multimode straight waveguide 43 connected in sequence.

[0097] According to an embodiment of the present disclosure, the first multimode input optical waveguide 111 , the second multimode input optical waveguide 112 , the first multimode straight waveguide 41 , and the second multimode straight waveguide 42 have the same waveguide cross-sectional dimensions.

[0098] According to an embodiment of the present disclosure, the first port 31 , the second port 32 , the third port 33 , and the fourth port 34 have the same waveguide cross-sectional dimensions as the first multimode input optical waveguide 111 , the second multimode input optical waveguide 112 , the first multimode straight waveguide 41 , and the second multimode straight waveguide 42 .

[0099] According to the embodiments of the present disclosure, it is necessary to reduce the crosstalk of optical signals of different modes and reduce the loss by adjusting the bending radius of the multimode waveguide bending structure 14. Optionally, special curves such as Euler curves and Bezier curves can be used to achieve adiabatic transformation, or multimode waveguide bending structures such as reverse design and sub-wavelength gratings can be used.

[0100] Fig.13 is a structural diagram of a multimode optical routing state switching unit according to another exemplary embodiment of the present disclosure.

[0101] According to the embodiments of the present disclosure, Fig.13As shown, the first multimode micro-ring optical modulation structure 121 is arranged between the first multimode input optical waveguide 111 and the first multimode output optical waveguide 151, the second multimode micro-ring optical modulation structure 122 is arranged between the second multimode input optical waveguide 112 and the second multimode output optical waveguide 152, the multimode phase shifter 22 is arranged away from the intersection of the first optical path and the second optical path, and the spacing between the first multimode input optical waveguide 111 and the first multimode micro-ring optical modulation structure 121, the spacing between the first multimode output optical waveguide 151 and the first multimode micro-ring optical modulation structure 121, the spacing between the second multimode input optical waveguide 151 and the second multimode micro-ring optical modulation structure 122, and the spacing between the second multimode output optical waveguide 152 and the second multimode micro-ring optical modulation structure 122 are all the same.

[0102] According to an embodiment of the present disclosure, taking the first multimode optical signal to be processed input from the first multimode input optical waveguide 111 as an example, when its wavelength is λ0, TE0 mode, if the resonant wavelength of the first multimode micro-ring optical modulation structure 121 is λ0 by adjusting the refractive index at this time, that is, the resonance condition is met, the first multimode optical signal will be coupled to the first multimode micro-ring optical modulation structure 121 at the first multimode input optical waveguide 111. At the same time, since the TE0 mode in the first multimode input optical waveguide 111 and the TE1 mode in the first multimode micro-ring optical modulation structure 121 meet the phase matching condition, the first multimode optical signal is converted from the TE0 mode to the TE1 mode and transmitted in the first multimode micro-ring optical modulation structure 121, and then coupled from the first multimode micro-ring optical modulation structure 121 to the first multimode output optical waveguide 151, and at the same time converted from the TE1 mode to the TE0 mode, and output from the first multimode output optical waveguide 151, showing a straight-through state.

[0103] According to the embodiments of the present disclosure, when the wavelength of the first multimode optical signal is λ0 and TE0 mode, the resonant wavelength of the first multimode micro-ring optical modulation structure 121 is not equal to λ0, that is, the resonance condition is not satisfied. At the first multimode input optical waveguide 111, the first multimode optical signal interferes and cancels with the optical signal newly coupled into the first multimode micro-ring optical modulation structure 121 after circling the first multimode micro-ring optical modulation structure 121 once, which is manifested as only a very small part of the first multimode optical signal being coupled into the first multimode micro-ring optical modulation structure 121 by the first multimode input optical waveguide 111. The first multimode optical signal directly passes through the first optical path in TE0 mode. Since the TE0 mode in the first optical path and the TE0 and TE1 modes in the second multimode micro-ring optical modulation structure 122 do not satisfy the phase matching condition, no coupling occurs at the second multimode output optical waveguide 152, so it is output from the second multimode output optical waveguide 152, showing a cross state.

[0104] According to the embodiment of the present disclosure, when the wavelength of the first multimode optical signal is λ0 and the TE1 mode, if the resonant wavelength of the second multimode micro-ring optical modulation structure 122 is λ0 by adjusting the refractive index at this time, that is, the resonance condition is met, since the TE1 mode in the first multimode input optical waveguide 111 and the TE0 and TE1 modes in the first multimode micro-ring optical modulation structure 121 do not meet the phase matching condition, coupling will not occur at the first multimode input optical waveguide 111, and the first multimode optical signal will directly pass through the first optical path and be coupled to the second multimode output optical waveguide 152. In the second multimode micro-ring optical modulation structure 122, since the TE1 mode in the second multimode output optical waveguide 152 and the TE0 mode in the second multimode micro-ring optical modulation structure 122 meet the phase matching condition, the first multimode optical signal is converted from the TE1 mode to the TE0 mode and transmitted in the second multimode micro-ring optical modulation structure 122, and then coupled from the second multimode micro-ring optical modulation structure 122 to the second multimode input optical waveguide 152, and at the same time converted from the TE0 mode to the TE1 mode, and then output from the first multimode output optical waveguide 151 through the second optical path, showing a straight-through state.

[0105] According to an embodiment of the present disclosure, when the wavelength of the first multimode optical signal is λ0 and TE1 mode, the resonant wavelength of the second multimode micro-ring optical modulation structure 122 is not equal to λ0, that is, the resonance condition is not met. When the first multimode optical signal is transmitted from the first multimode input optical waveguide 111 to the second multimode output optical waveguide 152 via the first optical path, the first multimode optical signal interferes and destructively with the optical signal newly coupled into the second multimode micro-ring optical modulation structure 122 after circling around the second multimode micro-ring optical modulation structure 122. This is manifested as the first multimode optical signal TE1 mode directly passing through the first optical path, so it is output from the second multimode output optical waveguide 152, which is manifested as a cross state.

[0106] The multi-mode optical routing state switching unit provided according to the embodiment of the present disclosure can realize the simultaneous regulation of optical signals of multiple modes. By simultaneously regulating the first multi-mode micro-ring optical modulation structure 121 and the second multi-mode micro-ring optical modulation structure 122, the simultaneous control of two mode routing states (i.e., the through state and the cross state) can be realized.

[0107] Fig.14 It is a schematic diagram of a multi-mode optical switch implemented based on a multi-mode optical routing state switching unit in an exemplary embodiment of the present disclosure.

[0108] According to the embodiments of the present disclosure, Fig.14 As shown, ten multimode optical routing state switching units (S1 to S10) are used, according to Spanke-Bene A five-port (I1-I5 / O1-O5) reconfigurable non-blocking multimode optical switch network is formed by cascading topological structures. Optionally, a mode division multiplexer or demultiplexer can be used as an auxiliary structure to achieve the coupling input of multiple modes to the multimode input optical waveguide module. Among them, the mode division multiplexer or demultiplexer can adopt an asymmetric directional coupler structure.

[0109] According to the embodiments of the present disclosure, the multi-mode optical routing state switching units are cascaded to form a multi-mode optical switch, which can achieve port expansion.

[0110] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0111] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A multimode optical routing state switching unit, characterized in that: include: Multimode input optical waveguide module, including: A first multimode input optical waveguide, used for inputting a first multimode optical signal to be processed; A second multimode input optical waveguide is used to input a second multimode optical signal to be processed; a multimode waveguide cross structure comprises a first optical path and a second optical path intersecting each other, one end of the first optical path is connected to the first multimode input optical waveguide, and one end of the second optical path is connected to the second multimode input optical waveguide; Multimode output optical waveguide module, including: a first multimode output optical waveguide connected to the other end of the second optical path, and a second multimode output optical waveguide, connected to the other end of the first optical path; Multimode micro-ring optical modulation structure module, including: Multimode phase shifter, including: Light guide structure, and a refractive index regulating structure configured to change the refractive index of the light guiding structure; A multimode microring resonator, wherein the resonant wavelength is related to the refractive index of the light-guiding structure. The multimode microring resonator is configured to couple the first multimode optical signal to the other end of the first optical path or the other end of the second optical path, and couple the second multimode optical signal to the other end of the first optical path or the other end of the second optical path in response to a change in the resonant wavelength.

2. The multimode optical routing state switching unit according to claim 1, characterized in that: The refractive index regulating structure changes the refractive index of the light guiding structure by using thermo-optic effect and electro-optic effect.

3. The multimode optical routing state switching unit according to claim 1, characterized in that: The multimode waveguide intersection structure also includes a first port, a second port, a third port and a fourth port, wherein the first port is connected to the first multimode input optical waveguide, the third port is connected to the second multimode input optical waveguide, the second port is connected to the first multimode output optical waveguide, and the fourth port is connected to the second multimode output optical waveguide, wherein the first port and the fourth port are connected to two ends of the first optical path, respectively, and the second port and the third port are connected to two ends of the second optical path, respectively.

4. The multimode optical routing state switching unit according to claim 3, characterized in that: The multimode micro-ring optical modulation structure module includes a first multimode micro-ring optical modulation structure and a second multimode micro-ring optical modulation structure, the first multimode micro-ring optical modulation structure is arranged between the first port and the second port, the second multimode micro-ring optical modulation structure is arranged between the third port and the fourth port, the multimode phase shifter is arranged at a place far away from the intersection of the first optical path and the second optical path, and the spacing between the first port and the first multimode micro-ring optical modulation structure, the spacing between the second port and the first multimode micro-ring optical modulation structure, the spacing between the third port and the second multimode micro-ring optical modulation structure, and the spacing between the fourth port and the second multimode micro-ring optical modulation structure are all the same.

5. The multimode optical routing state switching unit according to claim 3, characterized in that: The first multimode micro-ring optical modulation structure is arranged between the first multimode input optical waveguide and the first multimode output optical waveguide, the second multimode micro-ring optical modulation structure is arranged between the second multimode input optical waveguide and the second multimode output optical waveguide, the multimode phase shifter is arranged at a place far away from the intersection of the first optical path and the second optical path, and the spacing between the first multimode input optical waveguide and the first multimode micro-ring optical modulation structure, the spacing between the first multimode output optical waveguide and the first multimode micro-ring optical modulation structure, the spacing between the second multimode input optical waveguide and the second multimode micro-ring optical modulation structure, and the spacing between the second multimode output optical waveguide and the second multimode micro-ring optical modulation structure are all the same.

6. The multimode optical routing state switching unit according to claim 4, characterized in that: The waveguide heights of the multimode microring resonators of the first multimode microring optical modulation structure and the second multimode microring optical modulation structure are the same; the radius of the multimode microring resonator of the first multimode microring optical modulation structure is smaller than the radius of the multimode microring resonator of the second multimode microring optical modulation structure; the waveguide width of the multimode microring resonator of the first multimode microring optical modulation structure is larger than the waveguide width of the multimode microring resonator of the second multimode microring optical modulation structure.

7. The multimode optical routing state switching unit according to claim 4, characterized in that: The first port, the second port, the third port, and the fourth port have the same propagation constant as the multimode microring resonator, and the waveguide widths of the first port, the second port, the third port, and the fourth port are between the waveguide widths of the multimode microring resonator of the first multimode microring optical modulation structure and the waveguide widths of the multimode microring resonator of the second multimode microring optical modulation structure.

8. The multimode optical routing state switching unit according to claim 1, characterized in that: A multimode waveguide bending structure is respectively arranged between the multimode waveguide crossing structure and the first multimode input optical waveguide, the second multimode input optical waveguide, the first multimode output optical waveguide, and the second multimode output optical waveguide. The multimode waveguide bending structure includes a first multimode straight waveguide, a multimode bent waveguide, and a second multimode straight waveguide connected in sequence.

9. The multimode optical routing state switching unit according to claim 8, characterized in that: The first multimode input optical waveguide, the second multimode input optical waveguide, the first multimode straight waveguide and the second multimode straight waveguide have the same waveguide cross-sectional size.

10. A multimode optical switch, characterized in that: It comprises a multi-mode optical routing state switching unit as described in any one of claims 1-9.

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