Optical device, wavelength selective switch and optical device manufacturing method

Abstract

The present application relates to the technical field of optical fiber communications, and in particular to an optical device, a wavelength selective switch and an optical device manufacturing method. The optical device comprises a first part and a second part, wherein the second part is of a periodic structure formed by processing a material to be processed arranged on the surface of the first part, only one interface is arranged between the first part and the second part, the interface is the surface of the first part. The first part and the second part of the optical device provided by the present application are integrated into a whole, so that adverse factors influencing the optical performance of the optical device due to the use of a photolithography process can be avoided, and the reliability risk and the yield loss caused by the use of a photoresist or a bonding process can be reduced.

Description

Optical device, wavelength selective switch and optical device manufacturing method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 24, 2023, with application number 202310919329.7 and application name “An optical device, a wavelength selective switch and an optical device manufacturing method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical fiber communication technology, and in particular to an optical device, a wavelength selective switch, and a method for manufacturing the optical device. Background Art

[0003] A wavelength selective switch (WSS) is an optical module that can dispatch laser signals of different wavelengths from one or more input ports to one or more output ports in real time. Grisms are key components of WSSs, consisting of a prism and a grating. Grisms disperse and fold laser signals of different wavelengths according to their wavelengths.

[0004] Currently, common methods for fabricating prisms are to glue together two separate components, a planar grating and a prism, (method one), or to form grating stripes on the prism through etching (method two). However, the optical glue or bonding process used in the former (method one) suffers from low yields and large fluctuations (between 30% and 80%), high costs, and low production capacity. The latter (method two) requires extensive modifications to the prism surface lithography, resulting in high development costs.

[0005] Summary of the Invention

[0006] This application provides an optical device, a wavelength selective switch, and an optical device manufacturing method, which can address the existing issue of optical performance being affected by parameters such as duty cycle, sawtooth angle, and surface roughness, which are introduced by photolithography processes. The following describes this application from multiple perspectives, and the implementation methods and beneficial effects of the following aspects can be cross-referenced.

[0007] In a first aspect, the present application provides an optical device. Specifically, the optical device comprises: a first portion (e.g., a prism or optical encoder, described below); and a second portion (e.g., a grating or grating scale, described below). The second portion is a periodic structure formed by processing a material to be processed disposed on a surface of the first portion. The first portion and the second portion have only one interface, which is the surface of the first portion.

[0008] The above-mentioned optical device uses the first part as a substrate, and directly processes the material to be processed on the surface of the first part to form a periodic structure as the second part. The first part and the second part can be integrated into one without the need for photolithography, photoresist or bonding processes. Since the optical device is not formed by using photolithography, photoresist or bonding processes, there is only one interface between the first part and the second part of the molded optical device in the embodiment of the present application, and the interface is the surface of the first part. This arrangement can not only reduce the above-mentioned adverse factors affecting the optical performance caused by the photolithography process, but also reduce the reliability risk and yield loss caused by the photoresist or bonding process.

[0009] In a possible implementation of the first aspect above, the side of the second part facing away from the boundary surface includes a recess (such as the grating or grating groove of the grating scale described later), and the distance between the bottom surface of the recess and the boundary surface is less than 100 microns along the direction perpendicular to the boundary surface.

[0010] In one possible implementation of the first aspect, the material to be processed is a material to be imprinted, and the second portion is a periodic structure formed by imprinting and curing the material to be imprinted disposed on a surface of the first portion. That is, in this embodiment of the application, the first portion serves as a substrate, and the material to be imprinted is directly imprinted onto one surface of the first portion to form a periodic structure (serving as the second portion), thereby achieving the formation of the optical device.

[0011] It should be noted that the optical devices of the embodiments of the present application are not limited to being formed using an embossing process; other molding processes may also be used. Any device that meets the following conditions falls within the scope of protection of this application: The first and second parts of the optical device after molding have only one interface, which is the surface of the first part. For example, along a direction perpendicular to the interface, the distance between the bottom surface of the recess in the second part and the interface is less than 100 microns.

[0012] In one possible implementation of the first aspect, the first component is a prism comprising a non-parallel input surface and a reflective surface, the input surface being used to input an optical signal. The second component is a grating formed by machining the material to be processed, which is positioned on the reflective surface (i.e., the interface between the prism and the scale). In other words, the optical device is a spectroscopic device, also known as a grism.

[0013] It can be understood that the prism in the spectrometer refers to a dielectric block material (glass, crystal material, polymer, etc.) whose input surface is not parallel to the input surface, and the grating in the spectrometer refers to an optical element with a periodic structure integrated on its surface.

[0014] For example, the grating is formed by imprinting and curing the material to be imprinted on the reflective surface, without the need for a photolithography process or a photoresist or bonding process, and an integrated prism can be formed, thereby finely controlling the grating shape, improving the line density, and avoiding the problem of low yield when gluing the grating and prism together in the photoresist or bonding process.

[0015] The above-mentioned spectroscopic device forms a grating by imprinting and curing the material to be imprinted on the reflective surface of the prism, thereby integrating the grating and prism together to realize an integrated integrated prism solution. This can significantly increase the grating density based on existing equipment and processes, without the need to upgrade the ultraviolet light source to adapt to high line density and resolution. At the same time, the prism can avoid the reliability risks and yield loss introduced by optical glue or bonding processes, thereby improving the yield.

[0016] In a possible implementation of the first aspect, the grating density of the grating is between 2000 lines / mm and 20000 lines / mm.

[0017] It can be understood that the grating density will directly affect the dispersion angle of the grating. The greater the grating density, the greater the dispersion angle of the grating, and the higher the overall dispersion ability of the prism. The grating density of the spectrometer in the embodiment of the present application can be at a relatively high level (up to 20,000 lines / mm). Compared with the prior art, where the photolithography grating achieves a line density of 2000 lines / mm, the grating in the prism in the embodiment of the present application has better scalability. It should be noted that the upper limit of the grating density in the embodiment of the present application is not limited to 20,000 lines / mm, but can also be between 2000 lines / mm and 20,000 lines / mm, or below 2000 lines / mm.

[0018] In a possible implementation of the first aspect above, the grating includes a plurality of grating lines, which are periodically arranged along the extension direction of the reflecting surface, and along the lateral direction perpendicular to the extension direction, the grating line projection shapes of the plurality of grating lines include any one or more of a trapezoid, a rectangle, a sawtooth, and a triangle.

[0019] Because the grating is formed by imprinting and curing the imprinted material on the reflective surface of the prism in the present embodiment, the periodic structure of the grating can be adjusted according to different application scenarios. When a wider wavelength range (i.e., bandwidth) needs to be covered, the grating line projection shape of the multiple grating lines of the grism in the present embodiment can be adjusted to a rectangular or trapezoidal shape. When higher diffraction efficiency is required for a single wavelength, the grating line projection shape of the multiple grating lines of the grism in the present embodiment can be adjusted to a triangular or sawtooth shape.

[0020] In a possible implementation of the first aspect above, a surface of the grating is partially or completely covered with at least one dielectric film.

[0021] For example, when the refractive index of the grating region is less than 1.9, a high-refractive-index dielectric film needs to be applied to the grating surface to ensure diffraction efficiency. Furthermore, adding a low-refractive-index film to the high-refractive-index film can improve process tolerances and reduce manufacturing difficulty.

[0022] In a possible implementation of the first aspect above, the grating includes multiple grating lines, which are periodically arranged along the extension direction of the reflective surface, and the top surface and / or side surface of at least one of the multiple grating lines are covered with at least one dielectric film.

[0023] In a possible implementation of the first aspect above, the grating includes a plurality of grating grooves (i.e., recessed portions on the side of the grating facing away from the reflective surface), the plurality of grating grooves are spaced apart along an extension direction of the reflective surface, and at least one of the plurality of grating grooves is covered with at least one layer of dielectric film.

[0024] For example, along a direction perpendicular to the reflective surface, the distance between the bottom surface of the gate groove and the reflective surface is less than 100 micrometers.

[0025] In a possible implementation of the first aspect, the material of the dielectric film includes any one or more of TiO 2 , Ta 2 O 5 , and SiO 2 . In some possible implementations, the material of the dielectric film is a dielectric material with a high refractive index of 2.0 or above, such as a polymer material.

[0026] In one possible implementation of the first aspect, the first portion is an optical encoder; the second portion is an optical scale, and the optical scale is formed by machining a material to be machined located on a surface of the optical encoder (i.e., the interface between the optical encoder and the optical scale). For example, the optical scale is formed by embossing and curing the material to be imprinted located on the surface of the optical encoder.

[0027] In a possible implementation of the first aspect above, the grating scale includes a plurality of grating lines and a plurality of grating grooves (i.e., recessed portions on the back side of the grating scale), the plurality of grating lines are periodically arranged along the extension direction of the surface of the optical encoder, and each of the plurality of grating grooves is arranged at intervals between adjacent grating lines.

[0028] Exemplarily, along a direction perpendicular to the surface of the optical encoder, a distance between the bottom surface of the gate groove and the surface of the optical encoder is less than 100 micrometers.

[0029] In a possible implementation of the first aspect above, the gate line includes a first surface, and the gate groove includes a second surface; the first surface is the light-blocking area of ​​the optical encoder, and the second surface is the light-transmitting area of ​​the optical encoder, or the first surface is the light-transmitting area of ​​the optical encoder, and the second surface is the light-blocking area of ​​the optical encoder.

[0030] In a possible implementation of the first aspect above, the surface of the optical encoder includes any one of the upper and lower surfaces of a cuboid or a ring, a spherical surface, or the inner and outer surfaces of a cylinder.

[0031] A second aspect of the present application provides a wavelength selective switch, which includes the optical device in the first aspect and any one of the possible implementations of the first aspect.

[0032] A third aspect of the present application provides a method for manufacturing an optical device. The method comprises: providing a first portion; placing a material to be imprinted on a surface of the first portion; imprinting the material to be imprinted using an imprinting template having a predetermined shape, wherein the predetermined shape is periodically arranged along a direction parallel to an extension direction of the surface of the first portion; and curing and demolding the imprinted material to form a second portion on the surface of the first portion, wherein the first portion and the second portion have only one interface, which is the surface of the first portion.

[0033] The above-mentioned optical device does not use photolithography process or photoresist or bonding process in the process of directly imprinting the material to be imprinted on the surface of the first part to form the second part, so that the specific shape of the set shape of the second part that is periodically arranged in a direction parallel to the extension direction of the surface of the first part can be finely controlled, thereby improving the line density and avoiding the problem of low yield when the first part and the second part of the optical device are glued together in the photoresist or bonding process.

[0034] Furthermore, the second part of the embodiment of the present application is integrated with the first part through an all-in-one integration solution to form an integrated optical device. This significantly increases the density of the periodically arranged, pre-defined lines in the second part based on existing equipment and processes, providing greater scalability and avoiding the reliability risks and yield losses introduced by optical glue or bonding processes, thereby improving yield.

[0035] In a possible implementation of the third aspect, the second portion includes a recess on a side facing away from the interface, and a distance between a bottom surface of the recess and the interface is less than 100 micrometers along a direction perpendicular to the interface.

[0036] In a possible implementation of the third aspect above, the first part is a prism, which includes an input surface and a reflection surface that are not parallel to each other; the surface of the first part includes a reflection surface, and the material to be imprinted is set on the reflection surface; the set shape of the imprint template is periodically arranged along a direction parallel to the extension direction of the reflection surface; the second part is a grating, and the material to be imprinted forms a grating on the reflection surface of the prism after being demolded.

[0037] The process of forming the grating of the prism in the embodiment of the present application does not use a photolithography process or an optical glue or bonding process. Instead, the prism is directly used as the substrate, and the material to be imprinted (such as a polymer material or a glass material) is directly imprinted on the reflective surface of the prism into a grating periodic structure. That is, an imprinting process (such as a nanoimprinting process) is used to directly generate a periodic grating structure on the prism surface, thereby finely controlling the grating shape and improving the line density, thereby avoiding the problem of low yield when the grating and prism are glued together in the optical glue or bonding process. In addition, the grating of the embodiment of the present application is integrated with the prism through an integrated integration solution to form an integrated prism. It can greatly improve the grating density based on existing equipment and processes, has better scalability, avoids the reliability risks and yield loss introduced in the optical glue or bonding process, and improves the yield.

[0038] In a possible implementation of the third aspect, the grating density of the grating formed after printing and curing is between 2000 lines / mm and 20000 lines / mm.

[0039] It is understood that grating density directly affects the grating's dispersion angle. The greater the grating density, the greater the grating's dispersion angle, and the higher the overall dispersion capability of the prism. The spectrometer of the present embodiment can achieve a relatively high grating density (20,000 lines / mm). Compared to the existing technology where achieving a line density of 2,000 lines / mm with photolithographic gratings is challenging, the gratings in the prism of the present embodiment have greater scalability.

[0040] In a possible implementation of the third aspect above, the grating formed after imprinting and curing includes a plurality of grating lines, and the plurality of grating lines are periodically arranged along the extension direction of the reflecting surface, and along the lateral direction perpendicular to the extension direction, the grating line projection shapes of the plurality of grating lines include any one or more of a trapezoid, a rectangle, a sawtooth, and a triangle.

[0041] Because the grating is formed by imprinting and curing the imprinted material on the reflective surface of the prism, the periodic structure of the grating can be adjusted according to different application scenarios. When a wider wavelength range (i.e., bandwidth) needs to be covered, the grating line projection shape of the multiple grating lines of the prism in the embodiment of the application can be adjusted to a rectangular or trapezoidal shape. When higher diffraction efficiency is required for a single wavelength, the grating line projection shape of the multiple grating lines of the prism in the embodiment of the application can be adjusted to a triangular or sawtooth shape.

[0042] In a possible implementation of the third aspect, curing includes any one of thermal curing, UV curing, moisture curing, or thermoplastic curing. It should be noted that the curing method of the embodiment of the present application is not limited to this, and other curing and molding processes may also be used.

[0043] In a possible implementation of the third aspect, the surface of the grating is partially or completely covered with at least one dielectric film.

[0044] For example, when the refractive index of the grating region is less than 1.9, a high-refractive-index dielectric film needs to be applied to the grating surface to ensure diffraction efficiency. Furthermore, adding a low-refractive-index film to the high-refractive-index film can improve process tolerances and reduce manufacturing difficulty.

[0045] In a possible implementation of the third aspect, the grating includes a plurality of grating lines, which are periodically arranged along the extension direction of the reflective surface, and the top surface and / or side surface of at least one of the plurality of grating lines are covered with at least one dielectric film.

[0046] In a possible implementation of the third aspect, the grating includes a plurality of grating grooves, the plurality of grating grooves are spaced apart along an extension direction of the reflective surface, and at least one of the plurality of grating grooves is covered with at least one dielectric film.

[0047] In a possible implementation of the third aspect, a sputtering or epitaxial process is used to form the dielectric thin film. However, the process for forming the dielectric thin film is not limited thereto, and any process that can form a dielectric thin film on the grating surface falls within the scope of protection of this application.

[0048] In a possible implementation of the third aspect, the material of the dielectric film includes any one or more high-refractive-index dielectric materials such as TiO 2 , Ta 2 O 5 , SiO 2 or polymers.

[0049] In a possible implementation of the third aspect, the material to be imprinted includes a liquid polymer material.

[0050] In a possible implementation of the third aspect, the material to be imprinted includes a sol material capable of precipitating either ZrO 2 or SiO 2 at a set temperature.

[0051] It should be noted that the material to be imprinted is not limited to the above-mentioned liquid polymer material and sol material, but may also be other materials used to imprint a grating structure on a substrate.

[0052] In a possible implementation of the third aspect above, the first part is an optical encoder; the material to be imprinted is set on the surface of the optical encoder; the set shape of the imprinting template is periodically arranged along the extension direction of the surface of the optical encoder; the second part is a grating scale, and the material to be imprinted forms a grating scale on the surface of the optical encoder after demolding.

[0053] The manufacturing method of the optical encoder in the embodiments of this application demonstrates that the manufacturing method provided by the embodiments of this application can integrate gratings not only on planar surfaces to be imprinted, but also on surfaces of irregularly shaped materials. In other words, the materials to be imprinted with the grating can be non-standard shapes such as flat plates, prisms, or cylinders, and the surface to which the grating is bonded can be flat or non-planar, such as cylindrical or spherical surfaces. This offers a wider range of applications than prior art photolithographic gratings.

[0054] In a possible implementation of the third aspect above, the set shape of the imprint template includes multiple first areas and multiple second areas, and the multiple first areas and the multiple second areas are arranged at intervals, and along the lateral direction perpendicular to the extension direction of the surface of the optical encoder, the top surface of the projected shape of the multiple first areas is higher than the top surface of the projected shape of the multiple second areas.

[0055] In a possible implementation of the third aspect, the surface roughness of the first region is greater than the surface roughness of the second region; or the surface roughness of the first region is less than the surface roughness of the second region.

[0056] For example, if it is a translucent optical encoder, the bright area needs to be highly translucent, and at the same time, the dark area is contrasted with the bright area by means of coating to block light or forming a high-roughness matte surface, so that bright and dark areas appear alternately, so that when light passes through or reflects at the top (i.e., the grid line) or valley (i.e., the grid groove) of the periodic structure, a larger extinction ratio is formed.

[0057] In a possible implementation of the third aspect above, the grating scale includes a plurality of grating lines corresponding to the plurality of second regions, and a plurality of grating grooves corresponding to the plurality of first regions, the plurality of grating lines are periodically arranged along the extension direction of the surface of the optical encoder, and each of the plurality of grating grooves is arranged at intervals between adjacent grating lines.

[0058] In a possible implementation of the third aspect above, the gate line includes a first surface, and the gate groove includes a second surface; the first surface is the light-blocking area of ​​the optical encoder, and the second surface is the light-transmitting area of ​​the optical encoder, or the first surface is the light-transmitting area of ​​the optical encoder, and the second surface is the light-blocking area of ​​the optical encoder.

[0059] In a possible implementation of the third aspect, the surface of the optical encoder is any one of the upper and lower surfaces of a cuboid or a ring, a spherical surface, or the inner and outer surfaces of a cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG1 shows a schematic diagram of an application scenario in an optical communication network routing device;

[0061] FIG2 shows a schematic diagram of a wavelength selective switch;

[0062] FIG3 shows a schematic structural diagram of a wavelength selective switch provided in Example 1 of the present application;

[0063] FIG4a shows a schematic structural diagram of a light splitting element provided in Example 1 of the present application;

[0064] FIG4 b shows another schematic structural diagram of the light splitting element provided in Example 1 of the present application;

[0065] FIG5 shows a manufacturing process flow chart of an optical device provided in Example 1 of the present application, wherein FIG5(a) shows a manufacturing process flow chart 1 of the optical device, FIG5(b) shows a manufacturing process flow chart 2 of the optical device, and FIG5(c) shows a manufacturing process flow chart 3 of the optical device;

[0066] FIG6 shows a schematic structural diagram of a prism provided in Example 1 of the present application;

[0067] FIG7 shows a partial enlarged schematic diagram of the E region in FIG4a;

[0068] FIG8 is a schematic diagram showing the projection shape of the grating lines of the spectrometer element provided in the first embodiment of the present application, wherein FIG8(a) shows that the projection shape of the grating lines is a sawtooth shape, FIG8(b) shows that the projection shape of the grating lines is a triangle, and FIG8(c) shows that the projection shape of the grating lines is a rectangle;

[0069] FIG9 shows a graph showing wavelength-diffraction efficiency for different grating line projection shapes;

[0070] FIG10 is a schematic diagram showing various coverage conditions of the dielectric film of the spectrometer element provided in Example 1 of the present application on the grating surface. FIG10(a) shows that the top surface of the grating line is covered with a layer of dielectric film, FIG10(b) shows that the bottom wall of the grating groove is covered with a layer of dielectric film, FIG10(c) shows that the top surface of the grating line and the bottom wall of the grating groove are simultaneously covered with a layer of dielectric film, FIG10(d) shows that the surface of the grating line and the grating groove is covered with a layer of non-uniform dielectric film, and FIG10(e) shows that the surface of the grating line and the grating groove is covered with multiple layers of dielectric film.

[0071] FIG11 shows a schematic structural diagram of an optical encoder provided in Example 2 of the present application;

[0072] FIG12 shows another schematic structural diagram of an optical encoder provided in Example 2 of the present application;

[0073] FIG13 shows a partial enlarged schematic diagram of the F area in FIG7 and FIG8;

[0074] FIG14 shows another structural schematic diagram of the optical encoder provided in Example 2 of the present application;

[0075] FIG15 shows a fourth structural diagram of the optical encoder provided in Example 2 of the present application;

[0076] FIG16 shows a manufacturing process flow chart of an optical device provided in Example 2 of the present application, wherein FIG16(a) shows a manufacturing process flow chart 1 of the optical device, FIG16(b) shows a manufacturing process flow chart 2 of the optical device, and FIG16(c) shows a manufacturing process flow chart 3 of the optical device;

[0077] Figure 17 shows a schematic diagram of the distribution of bright and dark areas of the optical encoder provided in Example 2 of the present application. The optical encoder shown in Figure 17 (a) forms a dark area on the top and a bright area on the bottom. The optical encoder shown in Figure 17 (b) forms a bright area on the top and a dark area on the bottom. DETAILED DESCRIPTION

[0078] An embodiment of the present application provides an optical device comprising a first part (such as the prism and optical encoder described later) and a second part (such as the grating and grating scale described later). The first part is directly used as a substrate, and a second part having a periodic set shape is directly generated on the surface of the first part by an imprinting process, thereby forming an optical device in an integrated manner.

[0079] It can be understood that the optical device provided in the embodiment of the present application includes a grating used for a wavelength selection switch, but the embodiment of the present application is not limited to the grating, and can also be other optical devices, such as an optical encoder used to accurately detect the motion state of a mechanical device.

[0080] The following embodiments of the present application will first be described using a prism as an example of an optical device. The first part of the optical device is a prism, and the second part of the optical device is a grating. In the embodiments of the present application, a prism is directly used as a substrate, and a material to be imprinted (a polymer material or a glass material) is coated on the reflective surface of the prism. The material to be imprinted on the reflective surface of the prism is imprinted and cured using an imprinting process to form a periodic grating structure, thereby integrating the grating and prism together to achieve an integrated prism solution. This solution can significantly increase the grating density based on existing equipment and processes. Compared to the existing technology where achieving a line density of 2000 lines / mm for photolithographic gratings is a significant challenge, the grating in the prism of the embodiments of the present application has better scalability. At the same time, the prism of the embodiments of the present application can avoid the reliability risks and yield loss introduced by optical glue or bonding processes, thereby improving the yield.

[0081] To facilitate understanding of the technical solution of the present application, some concepts or terms involved in the embodiments of the present application are first explained.

[0082] (1) Wavelength Selective Switch (WSS)

[0083] A wavelength switch is an optical module that can dispatch laser signals of different wavelengths from one or more input ports to one or more output ports in real time.

[0084] (2) Wavelength Division Multiplexing (WDM)

[0085] Wavelength division multiplexing refers to the technology of transmitting two or more optical signals of different wavelengths in the same optical fiber of an optical line.

[0086] (3) Refractive index

[0087] The refractive index of a medium refers to the ratio of the speed at which light waves propagate in a vacuum to the speed at which light waves propagate in the medium.

[0088] (4) Grating

[0089] A grating is an optical element whose surface integrates periodic structures such as rectangles, sinusoids, sawtooths, triangles, or trapezoids. The number of periodic shapes per millimeter is called the grating's line density. When light waves of a specific wavelength are reflected or transmitted through the grating's surface, alternating light and dark stripes are produced. This phenomenon is called diffraction of light. Different bright stripes are called orders, and the ratio of the energy of the diffracted light to the input energy is called the diffraction efficiency. Light waves of different wavelengths produce bright or dark stripes at different positions and angles, a phenomenon called dispersion of light. The change in the light wave's output angle for every 1nm change in wavelength is called the dispersion angle. Gratings that utilize the ability to diffract light waves are also called diffraction gratings.

[0090] (5) Prism

[0091] A prism is a block of dielectric material (glass, crystal, polymer, etc.) whose input and output surfaces are not parallel. When light waves penetrate the interface between the prism and air, the propagation direction is deflected, which is called refraction of light. When different wavelengths penetrate the prism at the same angle, the propagation directions are different. This phenomenon is also called dispersion of light.

[0092] (6) Micro-Electro-Mechanical System (MEMS)

[0093] Microelectromechanical systems (MEMS) are an industrial technology that integrates microelectronics and mechanical engineering. In this article, they refer to a reverse mirror array whose angle is controlled by voltage. Their function is to adjust the direction of light reflected from each mirror in real time.

[0094] (7) Liquid Crystal On Silicon (LCOS)

[0095] Liquid crystal on silicon refers to a device in which the surface of an integrated circuit is smoothed using an advanced process and then coated with aluminum to serve as a reflector, forming an integrated circuit substrate. The integrated circuit substrate is then bonded to a glass substrate containing transparent electrodes, and liquid crystal is injected between the two substrates to encapsulate the device. Liquid crystal molecules will have different orientations under different electric fields, resulting in different refractive indices. The integrated circuit can control the voltage and electric field applied to each unit between the glass substrate and the integrated circuit substrate, thereby controlling the refractive index of the liquid crystal molecules in each unit, and thus controlling the reflection angle and direction of the light incident on that unit.

[0096] (8) Grism

[0097] Grisons are optical components that integrate gratings and prisms to achieve ultra-large dispersion angles.

[0098] (9) Insertion loss (IL)

[0099] Insertion loss refers to the energy loss of an optical signal when it passes through an interface, component, or system. It is generally measured in dB and is defined as shown in Equation 1.1, where Pin is the input optical power and Pout is the output optical power.

[0100] Polarization extinction ratio: refers to the ratio of the energies of the two perpendicular polarization components of a light signal, measured in dB, and defined as in Equation 1.2, where Px is the energy of the polarization component in a specified direction, and Py is the energy of the polarization component in the other direction perpendicular to Px.

[0101] The embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

[0102] FIG1 shows an application scenario of routing equipment in an optical communication network.

[0103] Specifically, as shown in Figure 1, there are multiple sites in this application scenario, such as Site A, Site B, Site C, Site D, and local server 200. Optical signals of different wavelengths (as shown in λ0, λ1, λ2, and λ3 in Figure 1) need to be distributed to different sites to complete the scheduling of signals of different wavelengths.

[0104] It should be noted that the application scenarios of the embodiments of the present application are not limited to the five sites shown in Figure 1 and the scheduling of optical signals of four different wavelengths. In some possible implementations, a corresponding number of sites can be set according to actual needs and the scheduling of optical signals of other numbers of wavelengths can be completed. For example, the optical communication network routing equipment includes six sites and needs to complete the scheduling of optical signals of five different wavelengths.

[0105] For example, the multiple sites represent cities A, B, C, and D, as well as a local server in city A. The multiple sites are connected via optical fibers for transmitting optical signals. For example, cities B and A are connected via optical fibers, cities A and C are connected via optical fibers, cities A and D are connected via optical fibers, and city A and server 200 are connected via optical fibers.

[0106] Referring to Figure 2, City A has a module capable of performing wavelength scheduling, namely, a wavelength selective switch (WSS) 100. When an optical signal λ0 (λ0 includes wavelengths λ1, λ2, and λ3) is sent from City B to City A, City A's wavelength selective switch 100 can distribute the optical signal λ0 with multiple wavelengths from the input port (i.e., City B) into optical signals of different wavelengths (as shown in λ1, λ2, and λ3 in Figures 1 and 2). It then schedules the optical signals of different wavelengths in real time to the corresponding multiple output ports (i.e., City A's local server 200, City C, and City D) according to the planned paths. After optical signal λ0 is transmitted from City B to City A via optical fiber, the wavelength selective switch 100 schedules the optical signal with wavelength λ1 to City A's local server 200, while the optical signals with wavelengths λ2 and λ3 are dispatched to City C and City D, respectively. Exemplarily, λ0 includes a light signal λ1 sent to the local server 200 in city A representing a WeChat Chinese emoticon, a light signal λ2 sent to city C indicating access to a Baidu server, and a light signal λ3 sent to city D.

[0107] FIG3 shows a schematic structural diagram of a spectrometer provided in an embodiment of the present application using a grism 105 as a wavelength selective switch 100. However, the spectrometer in an embodiment of the present application is not limited to a grism, but may also be other optical devices, such as a grating or a prism.

[0108] As shown in FIG3 , the wavelength selective switch 100 provided in an embodiment of the present application includes a fiber array 101, a lens array 102, a first reflector 103, a grism 105, and a second reflector 104. A single multi-wavelength optical signal (e.g., the multi-wavelength optical signal λ0 described above) enters the lens array 102 from the input port 106 of the fiber array 101 and is output to the first reflector 103. After being reflected by the first reflector 103, it is transmitted to the grism 105. After dispersion expansion by the grism 105, it is split into multiple single-wavelength optical signals and transmitted to the second reflector 104. The multiple single-wavelength optical signals after reflection are then dispersion folded by the grism 105. The spot shape and transmission direction are then adjusted by the reflector 103 and the lens array 102. Finally, they are sent to a specific output port 107 in the fiber array 101.

[0109] Specifically, the optical fiber array 101 is used to arrange optical fibers containing input and output signals (i.e., the optical fiber connecting input port 106 and the optical fiber connecting output port 107 shown in FIG3 ) in a certain order and distance (i.e., one input port 106 and four output ports 107 are spaced apart as shown in FIG3 ). One end of the optical fiber array 101 is connected to an external system (e.g., city B shown in FIG1 ) via an optical connector, and the other end of the optical fiber array 101 inputs a laser signal (i.e., multi-wavelength optical signal λ0) into a wavelength selective switch 100 (e.g., city A shown in FIG1 ).

[0110] Exemplarily, the fiber array 101 employs a V-groove or hole structure made of materials such as glass or silicon, securing the optical fibers of the fiber array 101 within the V-groove or hole structure. The lens array 102 comprises five lenses corresponding to one input port 106 and four output ports 107. Its purpose is to adjust the light spot emitted from the optical fiber at input port 106 or the reflected light spot from the first reflector 103 to a shape and energy distribution that meets the system's requirements, thereby converting divergent light into collimated light.

[0111] Exemplarily, the lens array 102 includes double-sided lenses and single-sided lenses, and the materials of the lenses include silicon, glass or polymer materials, etc. The embodiment of the present application does not impose specific restrictions on the shape and number of the lenses. In actual applications, according to system requirements, the shape of the lenses can be circular or square, and the surface shape of the lenses can be spherical, cylindrical, ellipsoidal or other aspherical surfaces, etc.

[0112] The first reflector 103 can change the direction of light transmission to transmit the light passing through the lens array 102 to the grism 105. At the same time, the first reflector 103 can fine-tune the reflection direction of light at different positions (for example, multiple single-wavelength optical signals after dispersion folding through the grism 105) to compensate for optical distortion caused by different optical paths.

[0113] In the aforementioned second reflector 104, the reflector surface is divided into different pixels, and each pixel can independently control its reflection direction. After the single multi-wavelength optical signal λ0 from the input port 106 is dispersed by the grating 105, the laser spots of multiple single-wavelength optical signals (i.e., λ1, λ2, and λ3 shown in FIG1 ) will fall on different positions (i.e., corresponding to the pixels on the second reflector 104) on the second reflector 104. The second reflector 104 controls the reflection direction of the single-wavelength optical signals at different positions based on the optical fiber arrangement position of the output port 107 in the optical fiber array 101. The reflected single-wavelength optical signals (i.e., λ1, λ2, and λ3 shown in FIG1 ) are then dispersed and folded by the optical splitter 105. The spot shape and transmission direction are then adjusted by the reflector 103 and the lens array 102. Finally, the signals are sent to the output ports 107 of the optical fiber array 101, which are arranged in a sequential order, for example, in the order of λ1, λ2, and λ3 shown in FIG3 , to complete wavelength scheduling.

[0114] Exemplarily, the second reflector 104 includes a MEMS reflector or an LCOS reflector, wherein the MEMS reflector adjusts the angle of the mirror by adjusting the driving voltage of each unit (i.e., corresponding to the above-mentioned pixel point) to achieve the purpose of controlling the reflection direction; while the LCOS controls the orientation of the liquid crystal molecules of each unit (i.e., corresponding to the above-mentioned pixel point) by controlling the driving voltage of the unit, thereby controlling its refractive index to achieve the purpose of controlling the reflection direction.

[0115] The specific structure of the grism 105 in the wavelength selective switch 100 will be further described below with reference to the accompanying drawings.

[0116] Please refer to Figures 4a and 4b. Figure 4a shows a first schematic diagram of the structure of a grism 105, and Figure 4b shows a second schematic diagram of the structure of the grism 105. The grisms 105 shown in Figures 4a and 4b both include a prism region 120 (including prisms 111) and a grating region 121 (including gratings 110). The grism 105 in Figure 4a includes an input surface 123, an output surface 123, and a reflective surface 124. The input surface 123 and the output surface 123 are located on the same side of the grism 105. The reflective surface 124 is non-parallel to the input surface 123 (Figure 4a shows a substantially perpendicular relationship, with the reflective surface 124 and the input surface 123 being arranged at angles of, for example, 85°, 86°, 87°, 90°, or 90.1°). The prism 105 shown in FIG4 b also includes an input surface 125, an output surface 126, and a reflective surface 124, wherein the input surface 125 and the output surface 126 are located on two different intersecting side surfaces of the prism 105, and the reflective surface 124 and the input surface 125 are also non-parallel to each other (as shown in FIG4 b , they are approximately perpendicular to each other).

[0117] As shown in Figures 4a and 4b, the input surfaces 123 and 125 of the grism 105 are used to input an optical signal (e.g., λ0), and the reflective surface 124 is used to disperse the optical signals from the input surfaces 123 and 125 to generate multiple single-wavelength optical signals (e.g., λ1, λ2, and λ3), which are then transmitted to the output surface, such as the output surface 123 in Figure 4a or the output surface 126 in Figure 4b. For example, the material of the prism 111 in the embodiment of the present application includes glass, transparent silicon, or a polymer material.

[0118] In the embodiment of the present application, the grating 110 in the spectroscopic device shown in FIG. 4 a and FIG. 4 b is formed by imprinting and curing the material to be imprinted on the reflective surface 124 of the prism 111 .

[0119] 5 and 6 , the process flow of forming the grating 110 on the surface of the prism 111 according to the embodiment of the present application will be described as follows:

[0120] As shown in (a) to (c) of FIG5 , the method for manufacturing the grism provided in the embodiment of the present application specifically includes the following steps:

[0121] S1: Provide a prism 111.

[0122] First, the prism 111 is fixed with a fixture. The prism 111 serves as a substrate. Referring to FIG. 6 , the prism 111 includes an input surface (such as the input surface 123 ) and a reflection surface 124 that are not parallel to each other.

[0123] Exemplarily, the prism 111 is an optical passive component manufactured using a processing technique. Exemplarily, the prism 111 can be a glass or silicon optical passive component manufactured using a machining process such as grinding and polishing, or a polymer optical passive component manufactured using a process such as injection molding or compression molding. Both the input surface 123 and the reflective surface 124 of the prism 111 are coated with an antireflection coating to reduce end face reflection.

[0124] S2: placing a material to be imprinted on the surface of the prism 111 .

[0125] Referring to FIG. 5( a ), a prism 111 is used as a substrate, and a material to be imprinted 131 is disposed on the reflective surface 124 of the prism 111. For example, the material to be imprinted 131 in the embodiment of the present application includes a liquid polymer material (e.g., a heat-curable / UV-curable polymer material). However, the material to be imprinted 131 in the embodiment of the present application is not limited to a polymer material and may also be other materials to be imprinted. For example, the material to be imprinted 131 may also include a sol material capable of precipitating either ZrO2 or SiO2 at a set temperature.

[0126] Exemplarily, the polymer material used for the imprinted material is a synthetic resin that undergoes a polymerization reaction under heating or UV light, crosslinking and curing to become an insoluble and infusible substance. Exemplarily, the synthetic resin includes phenolic, epoxy, amino, and polyacrylate. This material has high transmittance in the visible and near-infrared bands, with a refractive index between 1.4 and 1.8.

[0127] If two sol materials containing Zr, Si and O are selected, a chemical reaction is carried out at a certain temperature (within 500°C, such as 350°C, 400°C, 500°C) after subsequent imprinting and molding, and inorganic substances such as ZrO2 or SiO2 are precipitated and deposited on the surface of the prism 111 to form the grating 110 structure, and the organic substances are volatilized.

[0128] S3: Imprinting the material 131 using an imprint template 130 having a set shape, wherein the set shape is periodically arranged along a direction parallel to the extension direction of the reflective surface 124 of the prism 111 (as shown in the X direction in FIG5 ).

[0129] Referring to FIG5(b), after the upper surface of the prism 111 (i.e., the reflective surface 124) is coated with a liquid polymer material before curing (i.e., the material to be imprinted 131), an imprint template 130 engraved with a shape complementary to the grating 110 (as shown in FIG5(c)) is pressed onto the surface of the prism 111 coated with the polymer material (i.e., the material to be imprinted 131) to complete the imprinting (for example, a nanoimprinting process). Exemplarily, the imprinting direction is along a direction perpendicular to the reflective surface 124 (as shown in the Y direction in FIG5), wherein the set shape of the imprint template 130 is periodically arranged along a direction parallel to the extension direction of the reflective surface 124 (as shown in the X direction in FIG5(b)). Exemplarily, the periodic structure of the imprint template 130 is a trapezoidal structure. Correspondingly, the periodic structure of the grating 110 formed subsequently is also a trapezoidal structure. That is, the periodic structure of the grating 110 depends on the periodic structure of the imprint template 130.

[0130] Exemplarily, the material of the imprint template 130 includes any one of silicon, glass, metal or polymer materials, and the imprint template 130 can be processed by DUV / EBL lithography or high-precision single-point diamond machining to achieve a periodically arranged set shape (such as the periodic trapezoidal shape shown in Figure 5 (a)).

[0131] S4 : curing the imprinted material 131 and demolding the imprinted material 131 to form the grating 110 on the surface of the prism 111 .

[0132] Referring to FIG5(c), after imprinting is completed by pressing the imprint template 130 onto the reflective surface 124 of the prism 111 coated with the material to be imprinted 131, curing is further performed and the imprint template 130 is removed from the reflective surface 124 of the prism 111, leaving the cured shape of the grating 110 on the reflective surface 124 of the prism 111. In other words, after the material to be imprinted 131 is released from the mold, the grating 110 is formed on the reflective surface 124 of the prism 111, and the grating 110 and prism 111 are integrated into a grism 105.

[0133] Refer to Figure 7, which is an enlarged view of section E in Figure 4a. As shown in Figure 7, the prisms 111 and gratings 110 in the stamped grism 105 have only one interface: the reflective surface 124 of the prisms 111. For example, the curing conditions for the polymer described above vary depending on the material and can be thermally cured, UV-cured, or cured after a chemical reaction of the sol.

[0134] In summary, the process of forming the grating 110 from the grism 105 in the embodiment of the present application does not utilize photolithography or optical glue or bonding processes, thereby enabling precise control of the grating shape, improving line density, and avoiding the low yield problem encountered when gluing the grating and prism together in optical glue or bonding processes. Furthermore, the grating 110 in the embodiment of the present application is integrated with the prism 111 through an integrated solution to form an integrated grism. This significantly increases grating density based on existing equipment and processes, provides greater scalability, avoids the reliability risks and yield losses introduced in optical glue or bonding processes, and improves yield.

[0135] In the integrated grism 105, the prism 111 plays a certain role in dispersion spreading. This, combined with the dispersion effect of the grating region 121, forms the overall dispersion capability of the grism 105, thereby achieving a larger dispersion angle. This can shorten the distance between the first and second reflectors 103, 104, and the spectrometer 105 in the internal structure of the wavelength selective switch 100, bringing the first and second reflectors 103, 104 closer to the spectrometer 105, thereby reducing the size of the wavelength selective switch 100.

[0136] In addition, after the optical signal is dispersed by the grism 105, it will fall on different positions of the second reflector 104. When the dispersion angle of the grism 105 is larger, the spacing between different positions on the second reflector 104 is larger, which helps to reduce signal crosstalk between optical signals of adjacent wavelengths and affects the signal transmission between optical signals of adjacent wavelengths.

[0137] As shown in FIG7 , the grating 110 includes a plurality of grating lines 1101, which are periodically arranged along the extension direction of the reflective surface 124 (as shown in the X direction in FIG7 ). The grating 110 also includes a plurality of grating grooves 1102 (recesses on the side of the grating 110 facing away from the reflective surface 124), which are spaced apart along the extension direction of the reflective surface 124 (as shown in the X direction in FIG7 ).

[0138] It can be understood that the number of periodic shapes per millimeter is expressed as the grating density of the grating. In the prior art, due to the influence of the large-area light field uniformity and resolution of the grating etching process, the grating density is difficult to reach more than 2000 lines / mm. Since in the embodiment of the present application, the grating is formed by the process of imprinting and curing, the grating density (i.e., the density of the grating lines 1101) can reach 20,000 lines / mm by designing the periodic structure of the imprint template 130. The grating density will directly affect the dispersion angle of the grating. The greater the grating density, the greater the dispersion angle of the grating, and the higher the overall dispersion ability of the prism.

[0139] For example, along a lateral direction perpendicular to the extension direction (as shown in the X direction in FIG. 7 ), the projection shape of the plurality of grid lines 1101 is a trapezoidal structure. However, the embodiment of the present application does not limit the projection shape of the grid lines 1101. The periodic structure of the imprint template 130 can be adjusted according to different application scenarios and optical path designs to adjust the projection shape of the plurality of grid lines 1101 of the prism in the embodiment of the present application.

[0140] For example, in some possible embodiments, referring to (a), (b) and (c) in Figure 8, the grid line projection shapes include a zigzag shape (as shown in (a) in Figure 8), a triangle (as shown in (b) in Figure 8), and a rectangle (as shown in (c) in Figure 8).

[0141] Figure 9 shows a schematic diagram of diffraction efficiency curves for different grating line projection shapes at different wavelengths. Curve a corresponds to a sawtooth grating line projection shape, curve b corresponds to a triangle grating line projection shape, and curve c corresponds to a rectangular grating line projection shape. As shown in Figure 9, the bandwidth of curve a is smaller than that of curve b, which in turn is smaller than that of curve c. The diffraction efficiency of curve a is greater than that of curve b, which in turn is greater than that of curve c.

[0142] It can be seen from this that when the wavelength range (i.e., bandwidth) to be covered is wider, the grating line projection shape of the multiple grating lines 1101 of the grating in the embodiment of the present application can be adjusted to a rectangle or a trapezoid. When higher diffraction efficiency is required at a single wavelength, the grating line projection shape of the multiple grating lines 1101 of the grating in the embodiment of the present application can be adjusted to a triangle or a sawtooth.

[0143] In some possible implementations, referring again to FIG. 7 , the grism 105 provided in the embodiments of the present application is composed of a prism region 120, a grating region 121, and a dielectric film region 122. That is, a dielectric film is coated on the surface of the grating 110. Exemplarily, the material of the dielectric film includes any one or more of TiO2, Ta2O5, and SiO2.

[0144] It can be understood that dielectric film region 122 is a high-refractive-index dielectric film structure attached to the surface of grating 110. The actual reflection area of ​​the laser signal occurs at the interface between the dielectric film and grating region 121, and at the interface between the dielectric film and air. The laser signal is reflected at the interface between the dielectric film and air. When the incident angle and the exit angle satisfy the following relationship, the reflected light at different positions coherently constructively appears, indicating that more energy is emitted from this direction. mλ = d(sinα + sinβ)

[0145] Wherein, m is the diffraction order (or spectral order), λ is the wavelength of the incident light, d is the spacing between the grating grooves 1102 of the grating 110 structure, α is the incident angle, and β is the emission angle.

[0146] It should be noted that in the embodiment of the present application, when the refractive index of the grating region 121 is greater than 1.9, a dielectric film is not required on the surface of the grating 110. When the refractive index of the grating region 121 is less than 1.9, a high-refractive-index dielectric film is required to cover the surface of the grating 110 to ensure diffraction efficiency. In addition, adding a low-refractive-index film on the surface of the high-refractive-index film can improve process tolerance and reduce processing difficulty.

[0147] In addition, the embodiment of the present application does not limit the specific form of the dielectric film covering the surface of the grating 110.

[0148] In some possible embodiments, referring to Figures (a) to (e) of Figure 10 , the top surface and / or side surfaces (i.e., the sidewalls of the gate trench 1102) of at least one of the plurality of gate lines 1101 are covered with at least one dielectric film. Furthermore, at least one gate trench 1102 (i.e., the bottom wall of the gate trench 1102) of the plurality of gate lines 1101 is covered with at least one dielectric film. Continuing with Figure 7 , along a direction perpendicular to the reflective surface 124 (indicated by the Y direction in Figure 7 ), the distance between the bottom surface 11021 of the gate trench 1102 and the reflective surface (indicated by h in Figure 7 ) is less than 100 microns.

[0149] For example, as shown in (a) of FIG10 , the top surface of the gate line 1101 is covered with a dielectric film; as shown in (b) of FIG10 , the bottom wall of the gate groove 1102 is covered with a dielectric film; as shown in (c) of FIG10 , the top surface of the gate line 1101 and the bottom wall of the gate groove 1102 are both covered with a dielectric film; as shown in (d) of FIG10 , the surfaces of the gate line 1101 and the gate groove 1102 are covered with a non-uniform dielectric film; as shown in (e) of FIG10 , the surfaces of the gate line 1101 and the gate groove 1102 are covered with multiple layers of dielectric films, such as a first layer of dielectric film 1221 covering the grating surface and a second layer of dielectric film 1222 covering the first layer of dielectric film 1221.

[0150] Referring to Figures 11 to 15, in some application scenarios, such as the moving parts of some mechanical equipment (such as vehicle-mounted radars, machine tools, etc.), an optical encoder is required to accurately detect the motion state (including motion direction, motion speed and acceleration, displacement, etc.). The optical encoder is distributed with bright and dark areas with different reflection or transmission properties of light. When the light emitted by the light source 142 is transmitted or reflected by the optical encoder and enters the light detector 143, it will affect the strength of the signal received by the detector. The light detector 143 can calculate the motion state of the encoder (including speed, direction, displacement, etc.) by combining the corresponding algorithm. Identifying and analyzing the changes in the brightness and darkness of the received light can obtain accurate motion information. That is, the light detector 143 can obtain accurate motion information by identifying and analyzing the changes in the brightness and darkness of the received light.

[0151] The specific structure of the optical encoder will be further described below with reference to the accompanying drawings.

[0152] In some possible embodiments, referring to Figure 11, the optical device provided in the embodiment of the present application includes a first optical encoder 150 (the first part of the optical device) and a first grating scale 151 (the second part of the optical device). The first grating scale 151 is formed by imprinting and curing the material to be imprinted on the surface of the first optical encoder 150.

[0153] It is understood that the light emitted by light source 142 is transmitted through grating scale 151 of first optical encoder 150 and then enters light detector 143. Light detector 143 obtains accurate motion information by identifying and analyzing the brightness changes of the received light. For example, referring to FIG11 , first optical encoder 150 is a transmissive circular optical encoder, i.e., first optical encoder 150 uses a transmissive detection method. However, embodiments of the present application are not limited to transmissive optical encoders and may also use other detection methods.

[0154] For example, referring to FIG. 12 , in some possible implementations, the second optical encoder 152 is a reflective circular optical encoder, and the light emitted by the light source 142 is reflected by the second grating scale 153 of the second optical encoder 152 and then enters the light detector 143 .

[0155] In some possible embodiments, referring to Figure 13 and in combination with Figures 11 and 12, the first grating scale 151 and the second grating scale 153 both include a plurality of grating lines 1101 (i.e., protrusions extending outward along a surface perpendicular to the optical encoder in Figure 13) and a plurality of grating grooves 1102, the plurality of grating lines 1101 are periodically arranged along the extension direction of the surface of the optical encoder (as shown in the R direction in Figure 13), and each of the plurality of grating grooves 1102 is arranged at intervals between adjacent grating lines 1101.

[0156] Exemplarily, referring to FIG. 11 and FIG. 12 , the shape of the first optical encoder 150 includes a spherical shape or a cylindrical shape, but the embodiment of the present application is not limited thereto, and the optical encoder may also be in other shapes.

[0157] For example, referring to FIG. 14 , in some possible implementations, the third optical encoder 154 is a transmissive disc optical encoder, and the light emitted by the light source 142 is transmitted through the third grating scale 155 of the third optical encoder 154 and then enters the light detector 143 .

[0158] Also, referring to FIG. 15 , in some possible implementations, the fourth optical encoder 156 is a transmissive bar optical encoder, and the light emitted by the light source 142 is transmitted through the fourth grating scale 157 of the fourth optical encoder 156 and then enters the light detector 143 .

[0159] It can be understood that according to the motion characteristics of the moving parts (circular motion or linear motion), the shape of the optical encoder can be designed into any one of the above-mentioned spherical, cylindrical, rectangular and annular shapes, and the transmission or reflection detection method can also be adapted and selected according to the system requirements.

[0160] 16 , the process flow of forming a grating scale on the surface 1411 of the base 141 of the optical encoder according to the embodiment of the present application will be described as follows:

[0161] As shown in (a) to (c) of FIG16 , the manufacturing method of the optical encoder provided in the embodiment of the present application specifically includes the following steps:

[0162] S1: Provides optical encoder.

[0163] First, the optical encoder is fixed with a clamp. The optical encoder includes a base 141 , and the base 141 of the optical encoder serves as a substrate.

[0164] S2: placing the material to be imprinted on the surface of the optical encoder.

[0165] Referring to FIG. 16 (a), the base 141 of the optical encoder is used as a substrate, and a material to be imprinted 131 is provided on the surface 1411 of the base 141 of the optical encoder. The surface 1411 of the base 141 of the optical encoder includes any one of the upper and lower surfaces of a cuboid or a ring, a spherical surface, or the inner and outer surfaces of a cylinder. Exemplarily, the material to be imprinted 131 of the embodiment of the present application includes a liquid polymer material, but the material to be imprinted 131 of the embodiment of the present application is not limited to a polymer material, and can also be other materials to be imprinted. For example, the material to be imprinted 131 also includes a sol material that can precipitate any one of ZrO2 and SiO2 at a set temperature.

[0166] The polymer material used for the imprinting material is understood to be a synthetic resin that undergoes a polymerization reaction under heat or UV light, crosslinking and curing to become an insoluble and infusible substance. Examples of such synthetic resins include phenolic, epoxy, amino, and polyacrylate. These materials have high transmittance in the visible and near-infrared regions, with a refractive index between 1.4 and 1.8.

[0167] If two sol materials containing Zr, Si and O are selected, a chemical reaction is carried out at a certain temperature (within 500°C, such as 350°C, 400°C, 500°C) after subsequent embossing and molding, and inorganic substances such as ZrO2 or SiO2 are precipitated and deposited on the surface 1411 of the base 141 of the optical encoder to form a grating scale structure, and the organic matter is volatilized.

[0168] S3: Imprint the material 131 using an imprint template 130 having a set shape, wherein the set shape is periodically arranged in a direction parallel to the extension direction of the base 141 of the optical encoder (as shown in the X direction in FIG16 ).

[0169] After the surface of the base 141 of the optical encoder (i.e., the surface through which the light emitted by the light source 142 is transmitted or reflected, such as a strip surface or a disc surface) is coated with a liquid polymer material (i.e., the material to be imprinted 131) before curing, an imprinting template 130 engraved with a shape complementary to the grating scale (as shown in FIG16(c)) is pressed onto the surface of the base 141 of the optical encoder coated with the polymer material (i.e., the material to be imprinted 131) to complete the imprinting. The set shape of the imprinting template 130 is periodically arranged along a direction parallel to the extension direction of the base 141 of the optical encoder (as shown in the X direction in FIG16(b)). For example, the periodic structure of the imprinting template 130 is a trapezoidal structure.

[0170] Exemplarily, the material of the imprint template 130 includes silicon, glass, and metal, and the periodically arranged set shape is achieved by DUV / EBL lithography or high-precision single-point diamond machining.

[0171] S4: The embossed material 131 is cured and demolded to form a grating scale on the surface of the base 141 of the optical encoder.

[0172] Referring to FIG. 16( c ), after the imprinting template 130 is pressed onto the surface 1411 of the optical encoder base 141 coated with the material to be imprinted 131 and imprinting is completed (e.g., using a nanoimprint process), curing is further completed, and the imprinting template 130 is separated from the surface 1411 of the optical encoder base 141, leaving the cured grating scale shape on the surface 1411 of the optical encoder base 141. In other words, after demolding, the material to be imprinted 131 forms a grating scale on the surface of the optical encoder base 141, and the grating scale and optical encoder are integrated into a new optical device (i.e., a new integrated optical encoder with a grating scale). As shown in FIG. 16 , there is only one interface between the imprinted grating scale (i.e., the imprinted and cured material 131) and the surface 1411 of the optical encoder base 141, which is the surface 1411 of the optical encoder base 141.

[0173] For example, the curing conditions of the polymer mentioned above vary depending on the material, and may be thermal curing, UV curing, or curing after a chemical reaction of the sol.

[0174] In summary, the process of forming the grating scale on the surface 1411 of the base 141 of the optical encoder in the embodiment of the present application does not adopt a photolithography process, photo-glue or bonding process, so that the shape of the grating scale can be finely controlled, the line density can be improved, and the problem of low yield when the optical encoder and the grating scale are glued together in the photo-glue or bonding process can be avoided.

[0175] Furthermore, the grating ruler of the present embodiment is integrated with an optical encoder through an integrated solution to form an integrated optical encoder. This significantly increases the linear density of the grating ruler based on existing equipment and processes, provides better scalability, avoids the reliability risks and yield loss introduced by optical glue or bonding processes, and improves yield.

[0176] In other words, the manufacturing process of optical encoders that use nanoimprinting to imprint alternating light and dark structures and areas on the surface of moving strip, disk or wheel optical encoders can significantly reduce costs compared to traditional magnetic encoding processes, while the detection resolution can be improved to below sub-micron.

[0177] The manufacturing method provided in the embodiments of the present application can integrate a grating ruler not only on the surface of a flat material to be imprinted, but also on the surface of a shaped material to be imprinted. In other words, the material to be imprinted by the grating ruler can be a non-standard shape such as a flat plate, prism, or cylinder, and the surface to which the grating ruler is bonded can be a flat surface or a non-flat surface such as a cylindrical or spherical surface, thus having a wider range of applications than the photolithography grating rulers used in the prior art.

[0178] In some possible embodiments, referring to (c) in FIG16 and in combination with (a) and (b) in FIG17 , the set shape of the imprint template 130 for preparing the optical encoder provided in the embodiment of the present application includes a plurality of first regions 1103 and a plurality of second regions 1104, and the plurality of first regions 1103 and the plurality of second regions 1104 are arranged at intervals, and along the lateral direction perpendicular to the extension direction of the surface of the base 141 of the optical encoder (as shown in the X direction in FIG16 (c)), the top surface of the projected shape of the plurality of first regions 1103 is higher than the top surface of the projected shape of the plurality of second regions 1104.

[0179] In some possible embodiments, referring again to FIG16( c ), the surface roughness of the first region 1103 is less than the surface roughness of the second region 1104. Thus, the first region 1103 can be embossed to form a light-blocking area or a diffuse reflection area of ​​the grating scale, and the second region 1104 can be embossed to form a light-transmitting area or a light-reflecting area of ​​the grating scale.

[0180] Alternatively, in some other embodiments, the surface roughness of the first region 1103 is less than that of the second region 1104. Thus, the first region 1103 can be embossed to form a light-transmitting region or a light-reflecting region of the grating, and the second region 1104 can be embossed to form a light-blocking region or a diffusely reflecting region of the grating.

[0181] In some embodiments, referring to (a) and (b) of FIG17 and in combination with (c) of FIG16 , the grating scale for preparing an optical encoder provided in an embodiment of the present application includes a plurality of grating lines 1101 corresponding to the plurality of second regions 1104, and a plurality of grating grooves 1102 corresponding to the plurality of first regions, the plurality of grating lines 1101 being periodically arranged along the extension direction of the surface 1411 of the base 141 of the optical encoder (as shown in the X direction of (a) and (b) of FIG16 ), and each of the plurality of grating grooves 1102 being spaced apart between adjacent grating lines 1101. Continuing to refer to FIG17 , along a direction perpendicular to the reflective surface 124 (as shown in the Y direction of FIG17 ), the distance between the bottom surface of the grating groove 1102 and the surface 1411 of the base 141 of the optical encoder (as shown in m and n in FIG17 ) is less than 100 microns.

[0182] In some embodiments, referring again to FIG. 17( a ), the gate line 1101 includes a first surface (i.e., a dark region 144 ), and the gate groove 1102 includes a second surface (i.e., a bright region 145 ); the first surface is the light-blocking region of the optical encoder, and the second surface is the light-transmitting region of the optical encoder. That is, the optical encoder shown in FIG. 17( a ) forms a dark region 144 (i.e., a light-blocking region or a diffusely reflecting region) at the top of the periodic structure, or a bright region 145 (i.e., a light-transmitting region or a light-reflecting region) at the bottom.

[0183] For example, if it is a translucent optical encoder, the bright area 145 needs to be highly translucent, and at the same time, the dark area 144 is shielded by coating or forming a high-roughness matte surface to form a contrast with the top, so that the bright area 145 and the dark area 144 appear alternately, so that when the light passes through or reflects at the top (i.e., the gate line 1101) or the valley (i.e., the gate groove 1102) of the periodic structure, a larger extinction ratio is formed.

[0184] Alternatively, in some other embodiments, referring again to FIG17(b), the first surface (i.e., bright area 145) is a light-transmitting area of ​​the optical encoder, and the second surface (i.e., dark area 144) is a light-blocking area of ​​the optical encoder. Specifically, the optical encoder shown in FIG17(b) forms a dark area 144 (i.e., a light-blocking area or a diffuse reflection area) at the bottom of the periodic structure, or a bright area 145 (i.e., a light-transmitting area or a light-reflecting area) at the top.

[0185] In summary, the embodiments of the present application directly imprint and solidify the material to be imprinted on the reflective surface of the prism to form a grating, thereby integrating the grating and prism together to achieve an integrated grating solution. This solution can significantly increase the grating density based on existing equipment and processes, has better scalability, and avoids the reliability risks and yield loss introduced by optical glue or bonding processes, and the yield can be increased from 60% to over 90%. Alternatively, a grating scale can be integrated on the surface of an optical encoder, which has a wider range of applications compared to the photolithographic grating scale used in the prior art.

Claims

1. An optical device, characterized in that: include: Part I; The second part is a periodic structure formed by processing the material to be processed disposed on the surface of the first part. There is only one interface between the first part and the second part, and the interface is the surface of the first part.

2. The optical device according to claim 1, characterized in that The second portion includes a concave portion on a side facing away from the interface, and along a direction perpendicular to the interface, a distance between a bottom surface of the concave portion and the interface is less than 100 micrometers.

3. The optical device according to claim 1, characterized in that The material to be processed is a material to be imprinted, and the second part is a periodic structure formed by imprinting and curing the material to be imprinted disposed on the surface of the first part.

4. The optical device according to any one of claims 1 to 3, characterized in that: The first part is a prism, and the prism includes an input surface and a reflection surface that are not parallel to each other, and the input surface is used for inputting optical signals; The second part is a grating, and the grating is formed by processing the material to be processed arranged on the reflection surface.

5. The optical device according to claim 3, characterized in that The grating density of the grating is between 2000 lines / mm and 20000 lines / mm.

6. The optical device according to claim 4 or 5, characterized in that The grating includes a plurality of grating lines, which are periodically arranged along the extension direction of the reflecting surface. In the lateral direction perpendicular to the extension direction, the grating line projection shapes of the plurality of grating lines include any one or more of a trapezoid, a rectangle, a sawtooth, and a triangle.

7. The optical device according to any one of claims 4 to 6, characterized in that The surface of the grating is partially or entirely covered with at least one dielectric film.

8. The optical device according to claim 7, characterized in that The grating includes a plurality of grating lines, and the plurality of grating lines are periodically arranged along the extension direction of the reflection surface. The top surface and / or the side surface of at least one of the plurality of grating lines is covered with at least one layer of dielectric film.

9. The optical device according to claim 7 or 8, characterized in that The grating comprises a plurality of grating grooves, the plurality of grating grooves are arranged at intervals along the extension direction of the reflection surface, and at least one of the plurality of grating grooves is covered with at least one layer of dielectric film.

10. The optical device according to any one of claims 1 to 3, characterized in that: The first part is an optical encoder; The second part is a grating scale, and the grating scale is formed by processing the material to be processed which is arranged on the surface of the optical encoder.

11. The optical device according to claim 10, characterized in that The grating ruler includes a plurality of grating lines and a plurality of grating grooves. The plurality of grating lines are periodically arranged along the extension direction of the surface of the optical encoder, and each of the plurality of grating grooves is arranged at intervals between adjacent grating lines.

12. The optical device according to claim 11, characterized in that The gate line includes a first surface, and the gate groove includes a second surface; the first surface is a light-blocking area of ​​the optical encoder, and the second surface is a light-transmitting area of ​​the optical encoder, or the first surface is a light-transmitting area of ​​the optical encoder, and the second surface is a light-blocking area of ​​the optical encoder.

13. The optical device according to any one of claims 9 to 12, characterized in that The surface of the optical encoder includes any one of the upper and lower surfaces of a cuboid or a ring, a spherical surface, or the inner and outer surfaces of a cylinder.

14. A wavelength selective switch, characterized in that: An optical device comprising any one of claims 1 to 9.

15. A method for manufacturing an optical device, characterized in that: The manufacturing method comprises: Provide the first part; Disposing a material to be imprinted on a surface of the first portion; Imprinting the material to be imprinted using an imprint template having a set shape, wherein the set shape is periodically arranged along a direction parallel to an extension direction of the surface of the first part; The embossed material is cured and demolded to form a second part on the surface of the first part, and there is only one interface between the first part and the second part, and the interface is the surface of the first part.

16. The manufacturing method according to claim 15, characterized in that: The second portion includes a concave portion on a side facing away from the interface, and along a direction perpendicular to the interface, a distance between a bottom surface of the concave portion and the interface is less than 100 micrometers.

17. The manufacturing method according to claim 16, characterized in that: in, The first part is a prism, and the prism includes an input surface and a reflection surface that are not parallel to each other; The surface of the first part includes the reflective surface, and the material to be imprinted is arranged on the reflective surface; The set shapes of the imprint template are periodically arranged along a direction parallel to the extension direction of the reflective surface; The second part is a grating, and the material to be imprinted forms the grating on the reflection surface of the prism after demolding.

18. The manufacturing method according to claim 17, characterized in that: The grating density of the grating formed after printing and curing is 2000 lines / mm to 20000 lines / mm.

19. The manufacturing method according to claim 17 or 18, characterized in that: The grating formed after printing and curing includes a plurality of grating lines, which are periodically arranged along the extension direction of the reflecting surface. Along the lateral direction perpendicular to the extension direction, the grating line projection shapes of the plurality of grating lines include any one or more of a trapezoid, a rectangle, a sawtooth, and a triangle.

20. The manufacturing method according to any one of claims 17 to 19, characterized in that: The curing includes any one of thermal curing, UV curing, moisture curing or thermoplastic curing.

21. The manufacturing method according to any one of claims 17 to 20, characterized in that: The surface of the grating is partially or completely covered with at least one dielectric film.

22. The manufacturing method according to any one of claims 17 to 21, characterized in that: The grating includes a plurality of grating lines, and the plurality of grating lines are periodically arranged along the extension direction of the reflection surface. The top surface and / or the side surface of at least one of the plurality of grating lines is covered with at least one layer of dielectric film.

23. The manufacturing method according to any one of claims 17 to 22, characterized in that: The grating comprises a plurality of grating grooves, the plurality of grating grooves are arranged at intervals along the extension direction of the reflection surface, and at least one of the plurality of grating grooves is covered with at least one layer of dielectric film.

24. The manufacturing method according to claim 15, characterized in that: in, The first part is an optical encoder; Arranging the material to be imprinted on the surface of the optical encoder; The set shapes of the imprint template are periodically arranged along the extension direction of the surface of the optical encoder; The second part is a grating ruler, and the material to be imprinted forms the grating ruler on the surface of the optical encoder after demolding.

25. The manufacturing method according to claim 24, characterized in that: The set shape of the imprint template includes a plurality of first areas and a plurality of second areas, and the plurality of first areas and the plurality of second areas are arranged at intervals, and along the lateral direction perpendicular to the extension direction of the surface of the optical encoder, the top surface of the projected shape of the plurality of first areas is higher than the top surface of the projected shape of the plurality of second areas.

26. The manufacturing method according to claim 25, characterized in that: The surface roughness of the first region is greater than that of the second region; or the surface roughness of the first region is less than that of the second region.

27. The manufacturing method according to claim 25 or 26, characterized in that: The grating scale includes a plurality of grating lines corresponding to the plurality of second areas, and a plurality of grating grooves corresponding to the plurality of first areas, the plurality of grating lines are periodically arranged along the extension direction of the surface of the optical encoder, and each of the plurality of grating grooves is arranged at intervals between adjacent grating lines.

28. The manufacturing method according to claim 27, characterized in that: The gate line includes a first surface, and the gate groove includes a second surface; the first surface is a light-blocking area of ​​the optical encoder, and the second surface is a light-transmitting area of ​​the optical encoder, or the first surface is a light-transmitting area of ​​the optical encoder, and the second surface is a light-blocking area of ​​the optical encoder.

29. The manufacturing method according to any one of claims 24 to 28, characterized in that: The surface of the optical encoder includes any one of the upper and lower surfaces of a cuboid or a ring, a spherical surface, or the inner and outer surfaces of a cylinder.

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