Multi-state polarization signal controller based on chiral material

Abstract

The invention discloses a multi-state polarization signal controller based on a chiral material, and belongs to the technical field of functional photon chips. The cable is composed of a substrate layer, a lower cladding layer, a core layer and an upper cladding layer. In the light transmission direction, the core layer is composed of a cascade MMI light beam splitter, a connecting straight waveguide array and a chiral slab waveguide array, the cascade MMI light beam splitter and the connecting straight waveguide array are made of polymer photoresist materials, and the chiral slab waveguide array is made of chiral material doped polymer photoresist materials. Input linearly polarized light is introduced into the light beam splitter array, so that one beam of linearly polarized light is divided into multiple beams, the multiple beams of linearly polarized light pass through different chiral slab waveguides, and polarization state conversion of input light is achieved by means of optical rotation of chiral materials. Therefore, the defects that an existing polarization state controller is large in size and cannot achieve on-chip integration with a silicon-based photon chip are overcome. The device is simple and compact in structure, can be used for on-chip integration of optical waveguide chips, and realizes chip-level polarization state regulation and control.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional photonic chips, and in particular relates to a multi-state polarization signal controller based on chiral materials. Background Art

[0002] Polarization signal controllers are core optical devices in advanced optical systems and quantum communications. They precisely control the phase delay and polarization state distribution of a light beam to generate polarized optical signals. As polarization state manipulation units, these devices can be used to eliminate polarization-dependent losses in optical channels and provide stable polarization-encoded carriers for quantum key distribution. In fiber-optic sensing and quantum communication systems, random polarization state drift caused by environmental disturbances or device defects can degrade signal fidelity. Polarization signal controllers, with their high stability and programmability, can compensate for the resulting polarization state distortion in real time, significantly improving the system's anti-interference capabilities. However, traditional polarization controllers based on mechanical rotators or waveplate stacks suffer from bulky size and slow tuning speed, making them inadequate for the demands of high-density integrated optical systems and high-speed quantum communications. Against this backdrop, novel polarization signal controllers based on chiral materials have attracted considerable attention. These devices offer advantages such as compact size, the ability to generate arbitrary polarization states, and the ability to be deeply integrated with silicon-based photonic chips. They hold great promise as key technical support for next-generation polarization-encoded optical communications and quantum information processing systems, demonstrating broad application prospects. Summary of the Invention

[0003] The present invention aims to address the shortcomings of existing polarization signal controller technology by proposing a multi-state polarization signal controller based on chiral materials that can be integrated on-chip. During device fabrication, the optical rotation is controlled by controlling the doping ratio of the chiral material and photoresist, thereby controlling the ellipticity of the polarized light generated by the chiral slab waveguide at the output end. During device operation, multiple optical beam splitters are cascaded to achieve beam splitting of the optical path, allowing linearly polarized light at the input end to pass through the desired chiral slab waveguide and then be output from different ports in different polarization states. The present invention introduces input linearly polarized light into an optical beam splitter array to split a single beam of linearly polarized light into multiple beams, each of which passes through a different chiral waveguide. By doping the chiral material with the photoresist, the optical rotation of the chiral material is utilized to achieve polarization state conversion of the input light, thereby addressing the shortcomings of existing polarization state controllers, which are bulky and cannot be integrated on-chip with silicon-based photonic chips.

[0004] The multi-state polarization signal controller based on chiral materials described in the present invention is composed of a substrate layer 1, a lower cladding layer 2, a core layer 3 and an upper cladding layer 4 from bottom to top. The core layer 3 and the upper cladding layer 4 are located together on the lower cladding layer 2, and the core layer 3 is completely covered in the upper cladding layer 4. The refractive index of the lower cladding layer 2 and the upper cladding layer 4 is less than the refractive index of the core layer 3.

[0005] The multi-state polarization signal controller based on chiral materials described in the present invention is a single-input multi-output device, as shown in the attached Figure 1 As shown in (b), along the light transmission direction, the core layer 3 is composed of a cascaded MMI optical beam splitter 31, a connected straight waveguide array 36 and a chiral slab waveguide array 37.

[0006] The cascaded MMI optical beam splitter 31 is composed of three MMI optical splitters of the same structure, namely, a first MMI optical beam splitter, a second MMI optical beam splitter, and a third MMI optical beam splitter. The first MMI optical beam splitter is composed of a first input straight waveguide 32, a first input tapered waveguide 33, a first slab interference region 34, a first output tapered waveguide 351, and a second output tapered waveguide 352, which are connected in sequence. The second MMI optical beam splitter is composed of a second input straight waveguide 32', a second input tapered waveguide 33', a second slab interference region 34', a third output tapered waveguide 351', and a fourth output tapered waveguide 352', which are connected in sequence. The third MMI optical beam splitter is composed of a third input straight waveguide 32", a third input tapered waveguide 33", a third slab interference region 34", a fifth output tapered waveguide 351", and a sixth output tapered waveguide 352", which are connected in sequence.

[0007] The connecting straight waveguide array 36 is composed of a first connecting straight waveguide 361, a second connecting straight waveguide 362, a third connecting straight waveguide 363 and a fourth connecting straight waveguide 364;

[0008] The chiral slab waveguide array 37 consists of a first chiral slab waveguide 371, a second chiral slab waveguide 372, a third chiral slab waveguide 373 and a fourth chiral slab waveguide 374;

[0009] The first output tapered waveguide 351 and the second output tapered waveguide 352 are connected to the second input straight waveguide 32′ and the third input straight waveguide 32″ respectively. The third output tapered waveguide 351′, the fourth output tapered waveguide 352′, the fifth output tapered waveguide 351″ and the sixth output tapered waveguide 352″ are connected to the first connecting straight waveguide 361, the second connecting straight waveguide 362, the third connecting straight waveguide 363 and the fourth connecting straight waveguide 364 respectively. The first connecting straight waveguide 361, the second connecting straight waveguide 362, the third connecting straight waveguide 363 and the fourth connecting straight waveguide 364 are connected to the first chiral slab waveguide 371, The second chiral slab waveguide 372, the third chiral slab waveguide 373, and the fourth chiral slab waveguide 374 are connected; the first output tapered waveguide 351, the second output tapered waveguide 352, the second MMI optical beam splitter, and the third MMI optical beam splitter are symmetrical structures about the extension line of the symmetry center of the first slab interference region 34; the third output tapered waveguide 351' and the fourth output tapered waveguide 352' are symmetrical structures about the extension line of the symmetry center of the second slab interference region 34'; and the fifth output tapered waveguide 351" and the sixth output tapered waveguide 352" are symmetrical structures about the extension line of the symmetry center of the third slab interference region 34".

[0010] The material of the substrate layer 1 of the present invention is any one of indium phosphide, gallium arsenide, silicon, and silicon dioxide, which can be purchased and has a thickness of 500 to 1000 μm.

[0011] The lower cladding layer 2 and the upper cladding layer 4 of the present invention are made of any one of FSU-8 cladding photoresist, PMMA, and P (MMA-GMA) (the materials of the lower cladding layer 2 and the upper cladding layer 4 can be the same or different), and have a thickness of 3 to 5 μm.

[0012] The materials used for the cascaded MMI optical beam splitter 31 and the connected straight waveguide array 36 in the core layer 3 of the present invention are polymer photoresist materials; the material used for the chiral slab waveguide array 37 is a polymer photoresist material doped with a chiral material, and the doping mass of the chiral material is 0.5 to 5.0% of the total mass of the chiral material and the polymer photoresist material; the polymer photoresist material is any one of FSU-8 core layer photoresist and SU-8; the chiral material is any one of L-leucine, L-leucine methyl ester, N-methyl-L-leucine, D-leucine, and D-leucine methyl ester; and the thickness of the core layer 3 is 4 to 6 μm.

[0013] As attached Figure 2As shown, when the multi-state polarization signal controller based on chiral materials described in the present invention realizes the polarization signal control function, the input linearly polarized light λ (wavelength range is 1100~1600nm, power range is 0.2~2.0mW) is input by the optical beam splitter and transmitted in the core layer 3, and the optical path is split by the cascaded optical beam splitters, so that it passes through the chiral slab waveguide array 37. Under the action of the chiral slab waveguide, the polarization state of the input signal light is changed, thereby realizing the function of changing the polarization state of the output polarized light.

[0014] The function of chiral materials is to decompose linearly polarized light into left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components through the circular birefringence (CB) effect, and then recombining the two components to achieve polarization state conversion by utilizing the phase difference between the two. By adjusting parameters such as the chiral material concentration and waveguide length, a continuous ellipticity output from linear polarization to circular polarization can be precisely generated, thereby changing the polarization state of the output light.

[0015] In chiral waveguides, the constitutive equations are written in the form of the Drude-Born-Fedorov equations:

[0016]

[0017] ∈ and μ are the dielectric constant and magnetic permeability of the chiral waveguide, respectively, and γ is the chiral parameter. γ is related to circular birefringence (CB) and optical rotation (OR), CB = 2k0n 2 γ, Where k0 is the wave number in free space and n is the average refractive index. In an achiral waveguide, the electric field E and the magnetic field H are uncoupled in the longitudinal (z) component. In a chiral waveguide, the Drude-Born-Fedorov equation is The term couples these two fields together. Therefore, in a chiral waveguide, neither the TE mode nor the TM mode can exist, and the polarization mode can only be elliptical.

[0018] Compared with existing device structures and technologies, the present invention has the following beneficial effects:

[0019] (1) Compared with existing polarization signal controllers, the present invention has a simple and compact structure and can be used for on-chip integration of optical waveguide chips to achieve chip-level polarization state control;

[0020] (2) Compared with the existing polarization signal controller, the preparation method of the present invention is simple and can greatly simplify the process flow;

[0021] (3) Compared with the existing polarization signal controller, the materials used in the present invention are easy to obtain and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a structural schematic diagram of a multi-state polarization signal controller based on chiral materials described in the present invention; Figure (a) is a three-dimensional structural schematic diagram of the multi-state polarization signal controller based on chiral materials; Figure (b) is a top view of the multi-state polarization signal controller based on chiral materials; Figure (c) is a cross-sectional schematic diagram at position a in Figure (a); and Figure (d) is a cross-sectional schematic diagram at position b in Figure (a).

[0023] Figure 2 This diagram illustrates the operating principle of a chiral material-based multi-state polarization signal controller. Linearly polarized light passes through a first input straight waveguide 32 and enters a cascaded MMI optical beam splitter for splitting. Then, through a connected straight waveguide array, it enters a chiral slab waveguide array. Within the chiral slab waveguide array, the chiral material converts the incident light from an achiral linear polarization mode to a significantly elliptical polarization mode.

[0024] Figure 3 FIG1 is a schematic diagram of the device structure of Example 1 of the present invention; FIG1 (a) corresponds to FIG1 Figure 1 Schematic diagram of the cross section at position a in FIG; FIG (b) corresponds to the attached Figure 1 Figure (c) is a top view of the device of Example 1.

[0025] Figure 4 The device of embodiment 1 of the present invention is attached Figure 1 The polarization mode distribution of the output light at point b in (a) when the incident light is linearly polarized light with λ=1550 nm is represented by the normalized third Stokes parameter S3.

[0026] Figure 5 This is a flow chart of the preparation process of the device of Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be described more clearly and comprehensively below with reference to the accompanying drawings. Those skilled in the art will have a deeper understanding of the advantages and functions of the present invention through this description. However, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0028] Example 1

[0029] The substrate layer 1 selected in this embodiment is a silicon substrate with a thickness of 525 μm;

[0030] The lower cladding layer 2 and the upper cladding layer 4 selected in this embodiment are P (MMA-GMA) with a thickness of 3 μm;

[0031] In this embodiment, the chiral planar waveguide array 37 in the core layer 3 is made of L-leucine-doped FSU-8 core layer photoresist. The mass dosage of the chiral material L-leucine is 0.5%, 1%, 2%, and 5% of the sum of the mass of the chiral material and the FSU-8 core layer photoresist. The structural formula of L-leucine is shown below:

[0032]

[0033] As attached Figure 3 As shown, the thickness of the core layer 3 in this embodiment is 5 μm. The width of the first input straight waveguide 32, the second input straight waveguide 32', the third input straight waveguide 32", the first connecting straight waveguide 361, the second connecting straight waveguide 362, the third connecting straight waveguide 363 and the fourth connecting straight waveguide 364 is 3 μm, and the length is 300 μm; the width of the first input tapered waveguide 33, the second input tapered waveguide 33' and the third input tapered waveguide 33" gradually widens from 3 μm to 8 μm, and the length is 200 μm; the width of the first output tapered waveguide 351 and the second output tapered waveguide 352, the third output tapered waveguide 351' and the fourth output tapered waveguide 352', the fifth output tapered waveguide 351" and the sixth output tapered waveguide 352" gradually narrows from 8 μm to 3 μm, and the length is 200μm; the length of the first slab interference region 34, the second slab interference region 34' and the third slab interference region 34" are 3150μm, and the width is 30μm; the distance between the symmetry centers of the first output tapered waveguide 351 and the second output tapered waveguide 352, the third output tapered waveguide 351' and the fourth output tapered waveguide 352', the fifth output tapered waveguide 351" and the sixth output tapered waveguide 352" and the symmetry center of the slab interference region is 7.8μm; the length of the first chiral slab waveguide 371, the second chiral slab waveguide 372, the third chiral slab waveguide 373 and the fourth chiral slab waveguide 374 are 5000μm, and the width is 7μm; the overall length of the device is 13000μm, and the overall width is 75μm.

[0034] The preparation method of the core layer material of the FSU-8 core layer photoresist doped with the chiral material used in this embodiment is as follows:

[0035] 1. Take 0.0327g, 0.0658g, 0.1329g, and 0.3428g of L-leucine chiral material powder (doping mass concentration is 0.5%, 1%, 2%, and 5%, respectively) and place it in a clean weighing bottle, then add 10mL of FSU-8 core layer photoresist;

[0036] 2. Wrap the weighing bottle with tin foil and place it in an ultrasonic cleaner in the dark. Stir it ultrasonically at room temperature of 23°C for 2 hours (to ensure that the chiral material powder is completely dispersed in the FSU-8 core layer photoresist). The chiral material-doped FSU-8 core layer material can be obtained.

[0037] The central wavelength selected in this embodiment is 1550 nm, which is commonly used for long-distance transmission communications.

[0038] This embodiment uses COMSOL software to simulate the polarization distribution in the chiral slab waveguide when linearly polarized light with a wavelength of λ = 1550 nm is input. Due to the circular polarization characteristics of chiral materials, the chiral slab waveguide can only support circular polarization modes. Figure 4 It shows that within the effective mode region, the normalized third Stokes parameter S3 changes with the doping concentration of the chiral material, and gradually approaches +1 as the doping concentration increases from low to high. The polarization mode of the output light is left-handed elliptically polarized light with different ellipticities (ellipticity is defined as the ratio of the short axis to the long axis of circularly polarized light).

[0039] The preparation method of the multi-state polarization signal controller based on chiral materials described in this embodiment has the following steps: Figure 5 The specific description is as follows:

[0040] (1) Using silicon dioxide as the substrate layer 1, first clean the surface of the silicon dioxide. Place the silicon dioxide wafer in a beaker filled with acetone solution, ultrasonically clean it in an ultrasonic machine for 10 minutes, and then take it out; then place it in a beaker filled with isopropyl alcohol solution, ultrasonically clean it in an ultrasonic machine for 10 minutes, and then take it out; then place it in a beaker filled with deionized water, and ultrasonically clean it in an ultrasonic machine for 10 minutes; after taking it out, use a nitrogen gun to blow dry the deionized water on the surface of the silicon dioxide wafer; finally, place the silicon dioxide wafer in a glass container and put it in an oven to dry (150°C, 30 minutes) to remove surface moisture and organic impurities;

[0041] (2) Spin coating the FSU-8 cladding photoresist (rotation speed: 3800 rpm, time: 20 seconds) on the silicon dioxide surface cleaned in step (1), and immediately perform pre-baking on a hot plate to remove the solvent (60°C, 5 minutes; 90°C, 10 minutes; 120°C, 10 minutes); then place the obtained device in the exposure position of the photolithography machine, perform ultraviolet light exposure (25 mW, 90 seconds) without a mask, and then perform post-baking and curing on a hot plate (60°C, 5 minutes; 90°C, 10 minutes; 120°C, 10 minutes) to obtain the lower cladding 2;

[0042] (3) Spin-coating FSU-8 cladding photoresist (rotation speed: 3800 rpm, time: 30 seconds) on the surface of the lower cladding layer 2 obtained in step (2), and immediately performing pre-baking on a hot plate to remove the solvent (60°C, 5 minutes; 90°C, 10 minutes; 120°C, 10 minutes); placing the obtained device in the exposure position of the photolithography machine, and performing ultraviolet light exposure (24 mW, 112 seconds) using a photolithography mask, wherein the portion shielded by the photolithography mask is the core layer 3 structure, and the portion exposed by ultraviolet light is the cladding structure on both sides of the core layer, and then performing post-baking and curing on a hot plate (60°C, 5 minutes; 90°C, 10 minutes; 120°C, 10 minutes);

[0043] (4) The device obtained in step (3) is cooled to room temperature, placed in a developer for 2 seconds, taken out, placed in isopropyl alcohol to clean the developer, and then the isopropyl alcohol is cleaned with deionized water; the above steps of "placed in a developer for 2 seconds, taken out, placed in isopropyl alcohol to clean the developer, and then the isopropyl alcohol is cleaned with deionized water" are repeated twice to dissolve and remove the unexposed part covered by the mask, and finally placed on a hot plate for hardening (120°C, 10 minutes) to obtain a groove structure, and the undissolved part is the cladding part between the core layers;

[0044] (5) adding the core layer material to the groove structure obtained in step (4), wherein the optical beam splitter array (attached Figure 3 Undoped FSU-8 core layer photoresist is added to the cascade MMI optical beam splitter 31 and the straight waveguide array 36, and the four chiral slab waveguides (attached Figure 3 FSU-8 core photoresist doped with 0.5%, 1%, 2%, and 5% L-leucine was added dropwise to the chiral slab waveguide array (37). After UV exposure (25 mW, 112 seconds), thermal curing was performed (120°C, 10 minutes).

[0045] (6) performing plasma etching on the surface of the device obtained in step (5) to ensure that the interface between the core layer and the lower cladding layer is smooth and flat, thereby obtaining a core layer 3;

[0046] (7) Spin-coat the FSU-8 cladding photoresist (rotation speed: 3800 rpm, time: 20 seconds) on the surface of the device obtained in step (6), and immediately perform pre-baking on a hot plate to remove the solvent (60°C, 5 minutes; 90°C, 10 minutes; 120°C, 10 minutes); place the obtained device in the exposure position of the photolithography machine, perform ultraviolet light exposure (25 mW, 90 seconds) without a mask, and then perform post-baking and curing on a hot plate (60°C, 5 minutes; 90°C, 10 minutes; 120°C, 10 minutes) to obtain the upper cladding layer 4, thereby preparing a multi-state polarization signal controller based on chiral materials.

Claims

1. A multi-state polarization signal controller based on chiral materials, characterized by: The invention is composed of a substrate layer (1), a lower cladding layer (2), a core layer (3) and an upper cladding layer (4) from bottom to top, wherein the core layer (3) and the upper cladding layer (4) are located on the lower cladding layer (2), and the core layer (3) is completely covered in the upper cladding layer (4), and the refractive index of the lower cladding layer (2) and the upper cladding layer (4) is smaller than the refractive index of the core layer (3); Along the light transmission direction, the core layer (3) is composed of a cascaded MMI optical beam splitter (31), a connected straight waveguide array (36) and a chiral slab waveguide array (37); the cascaded MMI optical beam splitter (31) is composed of three MMI optical beam splitters with the same structure, namely, a first MMI optical beam splitter, a second MMI optical beam splitter and a third MMI optical beam splitter; the first MMI optical beam splitter is composed of a first input straight waveguide (32), a first input tapered waveguide (33), a first slab interference region (34), a first output tapered waveguide (351) and a third MMI optical beam splitter connected in sequence. The optical splitter is composed of a second output tapered waveguide (352), a second input tapered waveguide (33'), a second slab interference region (34'), a third output tapered waveguide (351') and a fourth output tapered waveguide (352') connected in sequence, and the optical splitter is composed of a third input straight waveguide (32"), a third input tapered waveguide (33"), a third slab interference region (34"), a fifth output tapered waveguide (351") and a sixth output tapered waveguide (352") connected in sequence; The connecting straight waveguide array (36) is composed of a first connecting straight waveguide (361), a second connecting straight waveguide (362), a third connecting straight waveguide (363) and a fourth connecting straight waveguide (364); the chiral slab waveguide array (37) is composed of a first chiral slab waveguide (371), a second chiral slab waveguide (372), a third chiral slab waveguide (373) and a fourth chiral slab waveguide (374); The first output tapered waveguide (351) and the second output tapered waveguide (352) are connected to the second input straight waveguide (32') and the third input straight waveguide (32"), respectively. The third output tapered waveguide (351'), the fourth output tapered waveguide (352'), the fifth output tapered waveguide (351") and the sixth output tapered waveguide (352") are connected to the first connecting straight waveguide (361), the second connecting straight waveguide (362), the third connecting straight waveguide (363) and the fourth connecting straight waveguide (364), respectively. The first connecting straight waveguide (361), the second connecting straight waveguide (362), the third connecting straight waveguide (363) and the fourth connecting straight waveguide (364) are connected to the first chiral slab waveguide ( The first output tapered waveguide (351) and the second output tapered waveguide (352), the second MMI optical beam splitter and the third MMI optical beam splitter are symmetrical structures about the extension line of the symmetry center of the first slab interference region (34); the third output tapered waveguide (351') and the fourth output tapered waveguide (352') are symmetrical structures about the extension line of the symmetry center of the second slab interference region (34'); and the fifth output tapered waveguide (351") and the sixth output tapered waveguide (352") are symmetrical structures about the extension line of the symmetry center of the third slab interference region (34").

2. The multi-state polarization signal controller based on chiral materials according to claim 1, characterized in that: The material of the substrate layer (1) is any one of indium phosphide, gallium arsenide, silicon and silicon dioxide, and the thickness is 500-1000 μm.

3. The multi-state polarization signal controller based on chiral materials according to claim 1, characterized in that: The materials of the lower cladding layer (2) and the upper cladding layer (4) are any one of FSU-8 cladding photoresist, PMMA, and P (MMA-GMA), and the thickness is 3 to 5 μm.

4. The multi-state polarization signal controller based on chiral materials according to claim 1, wherein: The materials used for the cascaded MMI optical beam splitter (31) and the connecting straight waveguide array (36) in the core layer (3) are polymer photoresist materials; the material used for the chiral planar waveguide array (37) is a polymer photoresist material doped with a chiral material, and the doping mass of the chiral material is 0.5 to 5.0% of the total mass of the chiral material and the polymer photoresist material; the polymer photoresist material is any one of FSU-8 core layer photoresist and SU-8; the chiral material is any one of L-leucine, L-leucine methyl ester, N-methyl-L-leucine, D-leucine, and D-leucine methyl ester; and the thickness of the core layer (3) is 4 to 6 μm.

5. The multi-state polarization signal controller based on chiral materials according to claim 1, characterized in that: Input linearly polarized light λ is inputted by a beam splitter and transmitted in the core layer (3), the wavelength range of λ is 1100-1600nm, and the power range is 0.2-2.0mW.

6. The multi-state polarization signal controller based on chiral materials according to claim 1, characterized in that: The thickness of the substrate layer (1) is 525 μm, the thickness of the lower cladding layer (2) and the upper cladding layer (4) is 3 μm, and the thickness of the core layer (3) is 5 μm; the width of the first input straight waveguide (32), the second input straight waveguide (32'), the third input straight waveguide (32"), the first connecting straight waveguide (361), the second connecting straight waveguide (362), the third connecting straight waveguide (363) and the fourth connecting straight waveguide (364) is 3 μm, and the length The width of the first input tapered waveguide (33), the second input tapered waveguide (33') and the third input tapered waveguide (33") is gradually widened from 3 μm to 8 μm, and the length thereof is 200 μm; the first output tapered waveguide (351) and the second output tapered waveguide (352), the third output tapered waveguide (351') and the fourth output tapered waveguide (352'), the fifth output tapered waveguide (351") and the sixth output tapered waveguide (351') are connected to the output tapered waveguide. The width of the chiral waveguide (352") is gradually narrowed from 8 μm to 3 μm, and its length is 200 μm; the length of the first slab interference region (34), the second slab interference region (34') and the third slab interference region (34") are 3150 μm and 30 μm in width; the distance between the symmetry center of the first output tapered waveguide (351), the second output tapered waveguide (352), the third output tapered waveguide (351'), the fourth output tapered waveguide (352'), the fifth output tapered waveguide (351") and the sixth output tapered waveguide (352") and the symmetry center of the slab interference region is 7.8 μm; the length of the first chiral slab waveguide (371), the second chiral slab waveguide (372), the third chiral slab waveguide (373) and the fourth chiral slab waveguide (374) are 5000 μm and 7 μm in width; the overall length of the device is 13000 μm and the overall width is 75 μm.

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