A high-performance polarization beam splitter based on silicon integration

Abstract

The present invention relates to a high-performance polarization beam splitter based on silicon integration, which includes an input waveguide, a coupling waveguide, and three anisotropic waveguides disposed within a silica cladding. The input waveguide, the coupling waveguide, and the anisotropic waveguides are arranged side by side in the same plane. The input waveguide and the coupling waveguide are respectively and correspondingly embedded in two slits formed by the three anisotropic waveguides. The outermost anisotropic waveguides are used to confine the evanescent field of the incident light, enabling the incident light to propagate along the input waveguide or the coupling waveguide. The middle anisotropic waveguide is used to couple the TM-polarized light in the incident light into the coupling waveguide. The output end of the input waveguide outputs TE-polarized light, and the output end of the coupling waveguide outputs TM-polarized light. The polarization beam splitter of the present invention has a simple structure, high splitting efficiency, and high polarization extinction ratio, improving the performance of the polarization diversity system.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technologies, especially the field of integrated photon device technologies, and particularly relates to a high-performance polarization beam splitter based on silicon integration. Background Art

[0002] A polarization beam splitter is a key device in an integrated optical system. Due to the common polarization correlation of integrated waveguides, incident light with different polarization states has different losses and phase shifts, making it impossible for optical signals to be stably transmitted or processed. To solve this problem, a polarization diversity method is proposed. First, the incident light is decomposed into two mutually orthogonal polarized lights, called TE polarized light and TM polarized light, and then they are processed separately. The core device in a polarization diversity system is the polarization beam splitter. Currently, the main polarization beam splitter schemes are the directional coupling type and the mode evolution type. The former has a simple structure but a large polarization crosstalk, while the latter has a large bandwidth but a large size. The prior art has also proposed a tapered polarization beam splitter based on a slit waveguide. This scheme requires growing multiple layers of different materials using the PECVD (Plasma Enhanced Chemical Vapor Deposition) process, which has a complex structure, resulting in high requirements for the manufacturing process and being difficult to control.

[0003] Therefore, it is necessary to develop a polarization beam splitter with a simple structure and a high polarization extinction ratio to improve the performance of the polarization diversity system. Summary of the Invention

[0004] Aiming at the technical problems existing in the prior art, the present invention provides a high-performance polarization beam splitter based on silicon integration, which solves the problems of the existing polarization beam splitter having a complex structure and a relatively low polarization extinction ratio, and improves the performance of the polarization diversity system.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A high-performance polarization beam splitter based on silicon integration includes an input waveguide, a coupling waveguide, and three anisotropic waveguides disposed in a silica cladding. The input waveguide, the coupling waveguide, and the anisotropic waveguides are arranged side by side in the same plane. The three anisotropic waveguides form two slits. The input waveguide is embedded in one of the slits, and the coupling waveguide is embedded in the other slit.

[0007] The outermost anisotropic waveguide is used to confine the evanescent field of the incident light, causing the incident light to propagate along the input waveguide or the coupling waveguide. The middle anisotropic waveguide is used to couple the TM polarized light in the incident light into the coupling waveguide.

[0008] The output end of the input waveguide outputs TE polarized light, and the output end of the coupling waveguide outputs TM polarized light.

[0009] Based on the above technical solutions, the present invention can also be improved as follows.

[0010] Preferably, it further includes a TE light output waveguide and a TM light output waveguide. The TE light output waveguide is docked with the output end of the input waveguide, and the TM light output waveguide is docked with the output end of the coupling waveguide.

[0011] Preferably, the TE light output waveguide and / or the TM light output waveguide is arc-shaped, and the output ends of the TE light output waveguide and the TM light output waveguide tend to be far away from each other.

[0012] Preferably, the bending radius range of the TE light output waveguide and / or the TM light output waveguide is 15 μm to 25 μm.

[0013] Preferably, taking the direction perpendicular to the plane where the input waveguide, the coupling waveguide, and the anisotropic waveguide are located as the height direction, the heights of the input waveguide, the coupling waveguide, and the anisotropic waveguide are equal.

[0014] Preferably, the anisotropic waveguide includes a plurality of slit waveguides arranged side by side and periodically with equal spacing, and the period is the distance between the center lines of adjacent slit waveguides.

[0015] Preferably, the duty cycle range of the slit waveguide is 0.4 to 0.6, and the duty cycle is the size ratio of the slit waveguide within a single period.

[0016] Preferably, the cross-sectional dimensions of the input waveguide and the coupling waveguide perpendicular to the optical axis are the same.

[0017] Preferably, the materials of the input waveguide, the coupling waveguide, the anisotropic waveguide, the TE light output waveguide, and the TM light output waveguide are silicon.

[0018] Preferably, the length range of the anisotropic waveguide along the optical axis direction is 13 μm to 15 μm.

[0019] The beneficial effects of the present invention are as follows: The high-performance polarization beam splitter based on silicon integration provided by the present invention utilizes the strong birefringence effect of the anisotropic waveguide. The anisotropic waveguide located between the input waveguide and the coupling waveguide divides the incident light into TE-polarized light and TM-polarized light. The TE-polarized light continues to propagate along the input waveguide, and the TM-polarized light is coupled into the coupling waveguide after passing through the anisotropic waveguide in the middle position for propagation, achieving high-efficiency splitting of the incident light. At the same time, the anisotropic waveguide located outside the input waveguide restricts the evanescent field of the incident light, enabling the incident light to propagate along the input waveguide or propagate from the anisotropic waveguide in the middle position to the coupling waveguide. The anisotropic waveguide located outside the coupling waveguide is used to ensure the symmetry of the waveguide structure and prevent the excitation of other modes and the generation of crosstalk when the cross-sectional shape of the waveguide changes suddenly. The polarization beam splitter of the present invention effectively reduces the optical power loss and improves the polarization extinction ratio of the polarization beam splitter. The device has a silica cladding and better compatibility with other silicon-based waveguide devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG. is a top view of the internal structure of a high-performance polarization beam splitter based on silicon integration according to the present invention;

[0021] Figure 2 FIG. is a schematic diagram of the optical path propagation of a high-performance polarization beam splitter based on silicon integration according to the present invention;

[0022] Figure 3 FIG. is a cross-sectional view of the coupling region perpendicular to the optical axis direction of a high-performance polarization beam splitter based on silicon integration according to the present invention;

[0023] FIG. 4(a) is a simulation diagram of the propagation of TE-polarized light in a preferred embodiment of the present invention; FIG. 4(b) is a simulation diagram of the propagation of TM-polarized light in a preferred embodiment of the present invention.

[0024] In the drawings, the list of components represented by each reference numeral is as follows:

[0025] 1, silica cladding; 2, input waveguide; 3, coupling waveguide; 4, anisotropic waveguide; 401, first anisotropic waveguide; 402, second anisotropic waveguide; 403, third anisotropic waveguide; 5, output waveguide; 501, TE light output waveguide; 502, TM light output waveguide. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0027] As Figure 1 shown is a top view of the internal structure of a high-performance polarization beam splitter based on silicon integration provided in this embodiment. As Figure 1As shown in the figure, a high-performance polarization beam splitter based on silicon integration provided in this embodiment includes an input waveguide 2, a coupling waveguide 3, and three anisotropic waveguides 4 disposed within a silica cladding 1. The input waveguide 2, the coupling waveguide 3, and the anisotropic waveguides 4 are arranged side by side in the same plane. The three anisotropic waveguides 4 form two slits. The input waveguide 2 is embedded in one of the slits, and the coupling waveguide 3 is embedded in the other slit.

[0028] The anisotropic waveguide 4 located outside the input waveguide 2 is used to confine the evanescent field of the TE polarized light in the incident light, so that the TE polarized light in the incident light propagates along the input waveguide 2. The anisotropic waveguide 4 located in the middle is used to couple the TM polarized light in the incident light into the coupling waveguide 3. The anisotropic waveguide 4 located outside the coupling waveguide 3 is used to ensure the symmetry of the waveguide cross-section structure and prevent the excitation of other modes and the generation of crosstalk when the waveguide cross-section shape changes abruptly.

[0029] The output end of the input waveguide 2 outputs TE polarized light, and the output end of the coupling waveguide 3 outputs TM polarized light.

[0030] It can be understood that the high-performance polarization beam splitter based on silicon integration provided by the present invention utilizes the strong birefringence effect of the anisotropic waveguide 4 to decompose the incident light into mutually orthogonal TE polarized light and TM polarized light. The TE polarized light continues to propagate along the input waveguide 2, and the TM polarized light is coupled into the coupling waveguide 3 through the anisotropic waveguide 4 in the middle for propagation, achieving high-efficiency splitting of the incident light.

[0031] More specifically, as Figure 1 shown, the three anisotropic waveguides 4 include a first anisotropic waveguide 401, a second anisotropic waveguide 402, and a third anisotropic waveguide 403 arranged side by side and parallel to each other. The input waveguide 2 is disposed in the slit formed between the first anisotropic waveguide 401 and the second anisotropic waveguide 402, and the coupling waveguide 3 is disposed in the slit formed between the second anisotropic waveguide 402 and the third anisotropic waveguide 403. The two ends (A end and B end) of the first anisotropic waveguide 401, the second anisotropic waveguide 402, and the third anisotropic waveguide 403 are flush, then Figure 1 the region between the A end and the B end in

[0032] is the coupling region of this polarization beam splitter. Figure 2Schematic diagram of the optical path propagation of a high-performance polarization beam splitter based on silicon integration. When the TE polarized light in the incident light enters the coupling region from the input waveguide 2, due to the presence of the first anisotropic waveguide 401 and the second anisotropic waveguide 402 on both sides of the input waveguide 2, the evanescent field of the TE polarized light is restricted within a very small range, and total internal reflection occurs during propagation, and it will not be coupled into the adjacent coupling waveguide 3, but directly output from the connected curved waveguide; when the TM polarized light in the incident light enters the coupling region from the input waveguide 2, at this time, the birefringence effect of the anisotropic waveguide 4 will reduce the confinement effect of the input waveguide 2 on the TM polarized light. When the coupling region between the A end and the B end is long enough, the TM polarized light can be completely coupled into the coupling waveguide 3 on the other side of the second anisotropic waveguide 402, thus realizing polarization beam splitting. As Figure 3 As shown in the cross-sectional view, the third anisotropic waveguide 403 is symmetrically arranged with the first anisotropic waveguide 401. More importantly, it is to ensure the symmetry of the waveguide cross-sectional structure to prevent the excitation of other modes and crosstalk when the waveguide cross-sectional shape changes suddenly. The polarization beam splitter of this embodiment effectively reduces the optical power loss and improves the polarization extinction ratio of the polarization beam splitter. And because the polarization beam splitter has a silica cladding 1, it has better compatibility with other silicon-based waveguide devices.

[0033] In one possible embodiment, the polarization beam splitter further includes a TE light output waveguide 501 and a TM light output waveguide 502. The TE light output waveguide 501 is docked with the output end of the input waveguide 2, and the TM light output waveguide 502 is docked with the output end of the coupling waveguide 3.

[0034] It can be understood that the TE light output waveguide 501 is used to output the TE polarized light that continues to propagate along the input waveguide 2 after beam splitting to the outside of the polarization beam splitter, and the TM light output waveguide 502 is used to output the TM polarized light that propagates along the coupling waveguide 3 after beam splitting to the outside of the polarization beam splitter, and is docked with the remaining components of the polarization diversity system through the TE light output waveguide 501 and the TM light output waveguide 502.

[0035] In one possible embodiment, the TE light output waveguide 501 and / or the TM light output waveguide 502 is arc-shaped, and the output ends of the TE light output waveguide 501 and the TM light output waveguide 502 tend to be far away from each other.

[0036] Due to the size limitation of the polarization beam splitter, the input waveguide 2 and the coupling waveguide 3 are arranged in parallel, and the gap size between their output ends is very small. It is necessary to lead out the two polarized lights to the connection ends of the remaining optical devices of the polarization diversity system through the curved TE light output waveguide 501 and / or TM light output waveguide 502 with a curvature. Therefore, the output ends of the TE light output waveguide 501 and the TM light output waveguide 502 tend to be far away from each other to facilitate docking with the optical devices of the subsequent optical path respectively.

[0037] In one possible embodiment, the bending radius range of the TE optical output waveguide 501 and / or the TM optical output waveguide 502 is 15 μm to 25 μm.

[0038] It can be understood that if the bending arc of the TM optical output waveguide 502 is too large, relatively large losses may be caused during the propagation of TM polarized light. Moreover, the smaller the bending radius, the larger the bending arc, and the greater the loss of TM polarized light. Therefore, it is preferably set that the bending radius range of the TM optical output waveguide 502 is 15 μm to 25 μm. To maintain the structural symmetry of the output end of the polarization beam splitter and facilitate the docking with the components of the subsequent optical path, the TE optical output waveguide 501 can be set to be symmetric with the TM optical output waveguide 502, that is, the bending radius range of the TE optical output waveguide 501 is also set to 15 μm to 25 μm.

[0039] In one possible embodiment, as Figure 3 shown in the cross-sectional view of the coupling region, taking the direction perpendicular to the plane where the input waveguide 2, the coupling waveguide 3, and the anisotropic waveguide 4 are located as the height direction, the heights of the input waveguide 2, the coupling waveguide 3, and the anisotropic waveguide 4 are equal to achieve efficient coupling of TM polarized light and improve the performance of the polarization beam splitter. At the same time, since the waveguide heights of the entire device are unified, all waveguide structures can be formed by only one etching process, which simplifies the production process flow of the polarization beam splitter and reduces the production process difficulty.

[0040] In one possible embodiment, as Figure 3 shown, the cross-sectional dimensions of the input waveguide 2 and the coupling waveguide 3 perpendicular to the optical axis are the same to achieve efficient coupling of TM polarized light, improve the performance of the polarization beam splitter, and at the same time simplify the production process flow of the polarization beam splitter and reduce the production process difficulty.

[0041] In one possible embodiment, the anisotropic waveguide 4 includes a plurality of slit waveguides arranged side by side and periodically arranged at equal intervals, and the period is the distance between the center lines of adjacent slit waveguides.

[0042] It can be understood that by periodically arranging multiple slit waveguides, on one hand, TE polarized light can be confined to propagate in the input waveguide 2, and on the other hand, TM polarized light can be coupled into the coupling waveguide 3. If the multiple slit waveguides are arranged with unequal spacings, it may cause non-uniform refractive index distribution and affect the light field transmission. In this embodiment, by arranging the multiple slit waveguides with equal spacings, the refractive index distribution of the anisotropic waveguide 4 is made uniform and the light field transmission is not affected. Regarding the overall size setting of the anisotropic waveguide 4, taking the direction perpendicular to the optical axis directions in the input waveguide 2 and the coupling waveguide 3 and perpendicular to the height direction described above as the width direction, the width dimension of the anisotropic waveguide 4 needs to be less than the wavelength of the TE polarized light. Regarding the number setting of the slit waveguides in the anisotropic waveguide 4, the number of periods, that is, the number of slit waveguides, if the number of periods of the slit waveguides is too small, it cannot play the role of isolating the TE polarized light (i.e., confining the evanescent field of the TE polarized light) and cannot confine it well to propagate in the input waveguide 2; if the number of periods of the slit waveguides is too large, the coupling efficiency of the TM polarized light may be reduced. Therefore, after experimental verification, the preferred range of the number of slit waveguides in a single anisotropic waveguide 4 in this embodiment is set to 3 to 7. As Figure 3 shown in the cross-sectional view of Figure 3 , in this embodiment, 5 slit waveguides are preferably arranged to form an anisotropic waveguide 4. These 5 slit waveguides are arranged side by side and periodically with equal spacings to form the metamaterial structure of the anisotropic waveguide 4. More specifically, these 5 slit waveguides are a group of periodic narrow waveguides parallel to the input waveguide 2 and the coupling waveguide 3, and their waveguide width is about 1 / 4 of the height, which is at the sub-wavelength level, so it is called a metamaterial structure. This structure has a large structural difference in the horizontal and vertical directions, so it has strong structural birefringence.

[0043] In one possible embodiment, the duty cycle range of the slit waveguide is 0.4 to 0.6, and the duty cycle is the size ratio of the slit waveguide in a single period.

[0044] It can be understood that as defined for the width direction above, the duty cycle here is defined as the width dimension ratio of the slit waveguide in a single period, that is, the ratio of the width dimension of the slit waveguide in a complete period length. By setting a preferable duty cycle, for example, the duty cycle of 0.5 is adopted in this embodiment, the slit waveguide can have good light field confinement ability.

[0045] In one possible embodiment, the materials of the input waveguide 2, the coupling waveguide 3, the anisotropic waveguide 4, the TE optical output waveguide 501, and the TM optical output waveguide 502 are silicon. These waveguides are fabricated on the silicon layer of an SOI (Silicon-On-Insulator) wafer. The optical waveguide device made of SOI material has the advantages of miniaturization and low loss. It also has the advantages of being compatible with microelectronic processes and being able to achieve monolithic integration of OEIC (Silicon-based Optoelectronic Integrated Circuit), which can improve the overall performance of the polarization diversity system.

[0046] In one possible embodiment, the length of the anisotropic waveguide 4 along the TE optical axis direction ranges from 13 μm to 15 μm. Theoretically speaking, the length of the anisotropic waveguide 4 determines the length of the coupling region. When the coupling region is long enough, the TM polarized light can be completely coupled into the adjacent coupling waveguide 3, thereby achieving ideal polarization beam splitting. However, due to the requirement of device miniaturization, considering the polarization beam splitting performance and the requirements of device size comprehensively, an optimal length range is obtained through experiments. For example, in this embodiment, the length of the anisotropic waveguide 4 is preferably set to 14 μm, that is, the length of the coupling region is set to 14 μm.

[0047] Since the polarization beam splitter provided in this embodiment has a simple structure, a regular shape, and the same height for each waveguide, its manufacturing process is simple, and the polarization beam splitter can be obtained by using a conventional etching method. Specifically, its manufacturing method is as follows:

[0048] After cleaning the SOI wafer, spin-coat photoresist on the surface of the SOI wafer to be processed;

[0049] Expose the photoresist through an electron beam to form a waveguide pattern;

[0050] After removing the photoresist, deposit a silica cladding layer 1 to fill the gaps between the waveguides and coat each waveguide.

[0051] In this process method, since the waveguide heights of the entire device are unified, all waveguide structures can be formed by only one etching process. The manufacturing process does not require the growth of multiple layers of materials, which simplifies the manufacturing process and reduces the process difficulty. During the deposition of the silica cladding layer 1, keep the input end of the input waveguide 2 and the output end of the output waveguide 5 exposed outside the silica cladding layer 1 to facilitate docking with other external devices.

[0052] As shown in Figure 4, it is a simulation diagram of polarization beam splitting using the preferred embodiment of the high-performance polarization beam splitter based on silicon integration provided by the present invention. The specific scenario of this preferred embodiment is as follows:

[0053] The polarization beam splitter in this implementation scenario includes a silica cladding 1 and an input waveguide 2, a coupling waveguide 3, a first anisotropic waveguide 401, a second anisotropic waveguide 402, a third anisotropic waveguide 403, and two curved output waveguides 5 disposed in the silica cladding 1. The thickness of the silica cladding 1 is between 2 μm and 5 μm, and the preferred value is 4 μm, which completely wraps other structures. The materials of the input waveguide 2 and the coupling waveguide 3 are silicon-based on SOI, and the cross-sectional dimensions of the two are the same. The width is between 400 nm and 500 nm, and the preferred value is 450 nm; the height is between 200 nm and 240 nm, and the preferred value is 220 nm. The materials of the first anisotropic waveguide 401, the second anisotropic waveguide 402, and the third anisotropic waveguide 403 are silicon-based on SOI. The three have the same structure and are distributed on both sides of the input waveguide 2 and the coupling waveguide 3 and between the input waveguide 2 and the coupling waveguide 3. Their cross-sectional heights are the same as those of the input waveguide 22 and the coupling waveguide 33. Each anisotropic waveguide 4 includes a group of periodic slit waveguide structures. The number of periods is between 3 and 7, and the preferred value is 5; the period is between 90 nm and 110 nm, and the preferred value is 100 nm; the duty cycle is between 0.4 and 0.6, and the preferred value is 0.5. As Figure 1 shown, in the coupling region between point A and point B, its length, that is, the distance between point A and point B, is between 13 μm and 15 μm, and the preferred value is 14 μm. The materials of the two curved output waveguides 5 are silicon-based on SOI, and include a TE light output waveguide 501 and a TM light output waveguide 502. Among them, the TE light output waveguide 501 is connected to the input waveguide 2, and the TM light output waveguide 502 is connected to the coupling waveguide 3. The bending radii of the two curved output waveguides 5 are between 15 μm and 25 μm, and the preferred value is 20 μm.

[0054] In Fig. 4(a), the darker-colored light rays represent TE polarized light, and the darker the gray scale, the more the energy distribution of TE polarized light. From the simulation diagram of Fig. 4(a), it can be seen that when light in the TE polarization state is incident from the input waveguide 2, due to the presence of the first anisotropic waveguide 401 and the second anisotropic waveguide 402 on both sides of the input waveguide 2, the evanescent field of the TE polarized light is restricted within a very small range, and total internal reflection occurs during propagation, and it will not be coupled into the adjacent coupling waveguide 3, and is directly output from the curved TE light output waveguide 501. In Fig. 4(b), the darker-colored light rays represent TM polarized light, and the darker the gray scale, the more the energy distribution of TM polarized light. From the simulation diagram of Fig. 4(b), it can be seen that when light in the TM polarization state is incident from the input waveguide 2, at this time, the birefringence effect of the second anisotropic waveguide 402 will reduce the confinement effect of the input waveguide 2 on the TM polarized light. Ideally, when the coupling region between point A and point B is long enough, the TM polarized light can be completely coupled into the adjacent coupling waveguide 3, thereby realizing polarization beam splitting.

[0055] The high-performance polarization beam splitter with silicon-based integration provided by the present invention utilizes the strong birefringence effect of the anisotropic waveguide 4. The anisotropic waveguide 4 located between the input waveguide 2 and the coupling waveguide 3 divides the incident light into TE-polarized light and TM-polarized light. The TE-polarized light continues to propagate along the input waveguide 2, and the TM-polarized light is coupled into the coupling waveguide 3 to propagate after passing through the second anisotropic waveguide 402 located in the middle position, achieving high-efficiency splitting of the incident light. At the same time, the first anisotropic waveguide 401 located outside the input waveguide 2 restricts the evanescent field of the incident light, enabling the TE-polarized light of the incident light to propagate along the input waveguide 2 and the TM-polarized light of the incident light to propagate along the second anisotropic waveguide 402 in the middle position towards the coupling waveguide 3. The anisotropic waveguide 4 located outside the coupling waveguide 3 is used to ensure the symmetry of the waveguide structure and prevent the excitation of other modes and crosstalk when the cross-sectional shape of the waveguide changes suddenly. The polarization beam splitter of the present invention effectively reduces the optical power loss and improves the polarization extinction ratio of the polarization beam splitter. The device has a silica cladding 1 and better compatibility with other silicon-based waveguide devices. Moreover, since the heights of the waveguides of the polarization beam splitter are consistent, the production process is simplified, and all the waveguides can be fabricated only by etching, reducing the production difficulty.

[0056] Similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0057] It should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the technical product is usually placed during use. It is only for the convenience of describing the present technology and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present technology. In addition, "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Therefore, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0058] In addition, terms such as "horizontal", "vertical", "overhanging", etc. do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0059] In the description of the present technology, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present technology can be understood according to specific situations.

[0060] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-performance polarization beam splitter based on silicon integration, characterized in that, It includes an input waveguide (2), a coupling waveguide (3), and three anisotropic waveguides (4) disposed within a silica cladding (1). The input waveguide (2), the coupling waveguide (3), and the anisotropic waveguides (4) are arranged side by side in the same plane. The three anisotropic waveguides (4) form two slits. The input waveguide (2) is embedded in one of the slits, and the coupling waveguide (3) is embedded in the other slit; The outermost anisotropic waveguides (4) are used to confine the evanescent field of the incident light, causing the incident light to propagate along the input waveguide (2) or the coupling waveguide (3); the middle anisotropic waveguide (4) is used to couple the TM-polarized light in the incident light into the coupling waveguide (3); Each anisotropic waveguide (4) includes multiple slit waveguides arranged side by side and periodically spaced at equal intervals. The duty cycle of the slit waveguides ranges from 0.4 to 0.

6. The duty cycle is the ratio of the size of the slit waveguide within a single period; the width of the slit waveguide is 1 / 4 of its height, and the width of the slit waveguide is at the sub-wavelength level; The output end of the input waveguide (2) outputs TE-polarized light, and the output end of the coupling waveguide (3) outputs TM-polarized light.

2. The high-performance polarization beam splitter based on silicon integration according to claim 1, characterized in that, It further includes a TE light output waveguide (501) and a TM light output waveguide (502). The TE light output waveguide (501) is docked with the output end of the input waveguide (2), and the TM light output waveguide (502) is docked with the output end of the coupling waveguide (3).

3. The high-performance polarization beam splitter based on silicon integration according to claim 2, characterized in that, The TE light output waveguide (501) and / or the TM light output waveguide (502) is arc-shaped, and the output ends of the TE light output waveguide (501) and the TM light output waveguide (502) tend to be far apart.

4. The high-performance polarization beam splitter based on silicon integration according to claim 3, characterized in that, The bending radius range of the TE light output waveguide (501) and / or the TM light output waveguide (502) is 15 μm to 25 μm.

5. The high-performance polarization beam splitter based on silicon integration according to claim 1, characterized in that, Taking the direction perpendicular to the plane where the input waveguide (2), the coupling waveguide (3), and the anisotropic waveguides (4) are located as the height direction, the input waveguide (2), the coupling waveguide (3), and the anisotropic waveguides (4) have the same height.

6. The high-performance polarization beam splitter based on silicon integration according to claim 1, characterized in that, The cross-sectional dimensions of the input waveguide (2) and the coupling waveguide (3) perpendicular to the optical axis are the same.

7. The high-performance polarization beam splitter based on silicon integration according to claim 2, characterized in that, The materials of the input waveguide (2), the coupling waveguide (3), the anisotropic waveguides (4), the TE light output waveguide (501), and the TM light output waveguide (502) are silicon.

8. The high-performance polarization beam splitter based on silicon integration according to claim 1, characterized in that, The length range of the anisotropic waveguide (4) along the optical axis direction is 13 μm to 15 μm.

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