Wavefront regulation and control module, wavelength selection switch and optical network equipment

Abstract

The embodiment of the invention discloses a wavefront regulation and control module, a wavelength selection switch and optical network equipment, and relates to the field of optical devices. The invention aims to improve the coupling efficiency of the wavefront regulation and control module. According to the specific scheme, the wavefront regulation and control module comprises a base layer, a filling layer and a plurality of metasurface optical elements. The base layer and the filling layer are stacked; the plurality of metasurface optical elements are located between the base layer and the filling layer; on the surface of the base layer, the arrangement path of the plurality of super-surface optical elements is arc-shaped. In the transmission process of the light beams in the wavelength selective switch, due to the fact that the positions of the input ports of the optical fiber array are different, the incident angles of the light beams, transmitted to the grating, of the input ports are different. And the light beam of each input port has position offset in the dispersion direction after being shaped by the grating. The plurality of metasurface optical elements are arranged in an arc shape, so that the energy loss caused by the deviation of the light beam in the dispersion direction after the light beam is shaped by the grating can be reduced, and the coupling efficiency of the wavefront regulation and control module is improved.

Description

Technical Field

[0001] This application relates to the field of optical devices, and more particularly to a wavefront modulation module, a wavelength selective switch, and an optical network device. Background Technology

[0002] The wavelength selective switch (WSS) is the core optoelectronic device of the reconfigurable optical add-drop multiplexer (ROADM). It can switch, attenuate, or block optical signals of any wavelength or combination of wavelengths at any port, and is one of the important devices in the current optical communication industry.

[0003] Currently, wavelength selective switches mainly include fiber arrays, wavefront modulation modules, optical systems, dispersive elements, switching engines, and output systems. Among them, the wavefront modulation module processes the light spot of the beam entering from the fiber array, the optical system controls the optical path and light spot size of the beam after passing through the wavefront modulation module, and the dispersive element can split or combine different wavelengths of light in the beam in space and illuminate the switching engine. The switching engine controls the angle deflection and attenuation of each wavelength of light, and then outputs the split or combined beams of different wavelengths through the fiber array in different directions.

[0004] The coupling efficiency of the wavefront modulation module of the wavelength selective switch in the existing technology needs to be improved. Summary of the Invention

[0005] This application provides a wavefront modulation module, a wavelength selective switch, and an optical network device. The aim is to improve the coupling efficiency of the wavefront modulation module.

[0006] To achieve the above objectives, this application adopts the following technical solution.

[0007] In a first aspect, embodiments of this application provide a wavefront modulation module. The wavefront modulation module includes a base layer, a filling layer, and multiple metasurface optical elements. The base layer and the filling layer are stacked; the multiple metasurface optical elements are all located between the base layer and the filling layer; on the surface of the base layer, the arrangement path of the multiple metasurface optical elements is arc-shaped. Thus, if multiple beams are transmitted to the wavefront modulation module, the beam spots of the multiple beams are arranged in an arc shape, and the multiple metasurface optical elements arranged in an arc shape can couple the multiple beams in an arc shape effectively. When this wavefront modulation module is applied to a wavelength selective switch, during the transmission of the beams through the wavelength selective switch, due to the difference in the position of each input port of the fiber array, the incident angle of the beam at each input port is different when it reaches the grating. Different incident angles of the beams at different input ports result in different equivalent periods of the grating, and the beams transmitted from each input port to different output ports exhibit different magnitudes of positional offset in the dispersion direction after grating shaping. The aforementioned multiple beams with positional offsets in the dispersion direction are received by the wavefront control module. Since the multiple metasurface optical elements are arranged in an arc shape, the energy loss caused by the beam offset in the dispersion direction after passing through the grating can be reduced, thereby improving the coupling efficiency of the wavefront control module.

[0008] In conjunction with the first aspect, in some feasible ways, the arrangement path of the plurality of metasurface optical elements is a symmetrical pattern. This results in better beam shaping and coupling efficiency for the wavefront modulation module.

[0009] In conjunction with the first aspect, in some feasible implementations, the symmetrical pattern is symmetrical about the axis of symmetry, and the distance between two adjacent metasurface optical elements along the extension direction of the axis of symmetry is greater than or equal to 1 μm. This results in better port position compensation for adjacent metasurface optical elements and improved coupling efficiency.

[0010] In conjunction with the first aspect, in some feasible implementations, the axis of symmetry is parallel to the dispersion direction of the wavefront modulation module. Thus, when the wavefront modulation module is applied to a wavelength selective switch, if the multiple beams emitted from the grating are positionally offset in the dispersion direction, the beams can be better coupled to the metasurface optical elements because the arrangement paths of the multiple metasurface optical elements are symmetrical about the axis of symmetry, which is parallel to the dispersion direction, thereby improving the coupling efficiency of the modulation module.

[0011] In conjunction with the first aspect, in some feasible ways, the distance between two adjacent metasurface optical elements is greater than or equal to 50 μm along a first direction, the first direction being perpendicular to the axis of symmetry of the symmetrical pattern.

[0012] In conjunction with the first aspect, in some feasible ways, the surface of the filler layer away from the base layer is planar. This allows for a higher degree of adhesion when the surface of the filler layer away from the base layer is bonded to other structural components.

[0013] In conjunction with the first aspect, in some feasible embodiments, each of the metasurface optical elements comprises an array of multiple nanopillars, the vertical projection of which onto the substrate is a centrally symmetric pattern. Thus, if only the polarization state of the light beam transmitted to the metasurface optical element is changed, the metasurface optical element consistently shapes the beam, meaning the metasurface optical element exhibits polarization-independent characteristics.

[0014] In conjunction with the first aspect, in some feasible ways, the vertical projection of the nanopillars onto the substrate is a circle or a square.

[0015] In conjunction with the first aspect, in some feasible embodiments, each of the metasurface optical elements comprises an array of multiple nanopillars, the vertical projection of which onto the substrate is a non-centrosymmetric pattern. Thus, when beams of light with different polarization directions are transmitted to the nanopillars, the nanopillars exert different phase and amplitude modulation effects on the beams, achieving independent beam size shaping effects.

[0016] In conjunction with the first aspect, in some feasible embodiments, the substrate material includes silicon oxide. Silicon oxide has the advantages of low refractive index and low optical loss. Substrates including silicon oxide also have the advantages of low refractive index and low optical loss.

[0017] In conjunction with the first aspect, in some feasible embodiments, the material of the metasurface optical element includes at least one of silicon, titanium dioxide, silicon nitride, or gallium nitride. Silicon, titanium dioxide, silicon nitride, or gallium nitride have high refractive indices.

[0018] In conjunction with the first aspect, in some feasible embodiments, the filler layer is made of silicon dioxide or polymethyl methacrylate (PMMA). Silicon dioxide or PMMA has low optical loss. The light beam experiences less loss as it passes through the filler layer.

[0019] Secondly, embodiments of this application provide a wavelength selective switch. The wavelength selective switch includes: a grating and any of the wavefront modulation modules provided in the first aspect; the wavefront modulation module is used to shape the light beam and transmit the light beam to the grating, and the wavefront modulation module is also used to receive the light beam from the grating in the reverse direction. Because any of the wavefront modulation modules provided in the first aspect has high efficiency in coupling the light beam, the energy consumption of the wavelength selective switch can be reduced.

[0020] In conjunction with the second aspect, in some feasible implementations, the wavelength selective switch further includes a transparent body. Both the grating element and the wavefront modulation module are connected to the transparent body. Thus, at least a portion of the optical path between the wavefront modulation module and the grating is within the transparent body. The wavefront modulation module, grating, and transparent body do not require hermetic packaging, reducing packaging difficulty and cost. Furthermore, integrating the wavefront modulation module and grating onto the transparent body increases the integration density of the wavelength selective switch and reduces its size.

[0021] In conjunction with the second aspect, in some feasible embodiments, the substrate is bonded to the transparent body, and the substrate and the transparent body have the same refractive index; thus, during the transmission of the light beam between the filler layer and the transparent body, the change in the light transmission direction is small or almost unchanged, resulting in minimal light loss during beam penetration. Alternatively, the filler layer is bonded to the transparent body, and the filler layer and the transparent body have the same refractive index. Thus, during the transmission of the light beam between the substrate and the transparent body, the change in the light transmission direction is small or almost unchanged.

[0022] Thirdly, embodiments of this application provide an optical network device. The optical network device includes an optical fiber and any of the wavelength selective switches provided in the second aspect above. The optical fiber is connected to the wavelength selective switch. Therefore, the wavelength selective switch provided in the second aspect above has lower power consumption, which can reduce the losses of the optical network device. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an optical communication network provided in an embodiment of this application.

[0024] Figure 2 A schematic diagram of a multi-wavelength selective switch.

[0025] Figure 3a This is a schematic diagram of a wavelength selective switch.

[0026] Figure 3b This is a schematic diagram of another type of wavelength selective switch.

[0027] Figure 4 This is a schematic diagram of the wavefront control module provided in an embodiment of this application.

[0028] Figure 5 This is a schematic diagram of the structure of multiple metasurface optical elements and substrates provided in the embodiments of this application.

[0029] Figure 6 This is a schematic diagram of the structure of a metasurface optical element provided in an embodiment of this application.

[0030] Figure 7This is a graph showing the relationship between the size of the nanopillars and the response phase.

[0031] Figure 8 This is a schematic diagram of another metasurface optical element provided in an embodiment of this application.

[0032] Figure 9 This is a schematic diagram showing the exploded structure of the wavefront modulation module and fiber array provided in the embodiments of this application.

[0033] In the diagram: 10-Optical communication network; 20-Optical network equipment; 100-Wavelength selective switch; 110-Fiber array; 120-Grate; 130-Optical switching engine; 140-Transparent body; 150-Curved mirror; 160-Spherical mirror; 210-Base layer; 220-Filling layer; 230-Metasurface optical element; 231-Nanopillar; 111-Fiber; 200-Wavefront modulation module. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0035] In the following description, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0036] Furthermore, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0037] Figure 1 Please refer to the schematic diagram of the structure of an optical communication network 10 provided in this application embodiment. Figure 1 The optical communication network 10 includes multiple optical network devices 20. The optical network devices 20 include reconfigurable optical add-drop multiplexers (OADMs) or optical cross-connects (OXCs), etc. The multiple optical network devices 20 are interconnected via optical channels.

[0038] The optical network device 20 includes a wavelength selection switch 100, and wavelength division multiplexing technology is implemented between multiple optical network devices 20 through the wavelength selection switch 100.

[0039] Figure 2 A schematic diagram of the structure of a multi-wavelength selection switch 100. (See diagram below.) Figure 2 As shown, the wavelength selection switch 100 implements wavelength scheduling functions across different dimensions. The wavelength selection switch 100 has the function of outputting the input wavelength from any output port, thereby enabling optical network devices 20 (such as...) to... Figure 1 As shown, it can configure any wavelength on any port.

[0040] This application embodiment does not limit the number of wavelength selection switches 100 in the optical network device 20. For example, the wavelength selection switches 100 in the optical network device 20 can be one, two, three, four or more.

[0041] Figure 3a Please refer to the schematic diagram of a wavelength selective switch 100. Figure 3a The wavelength selection switch 100 includes: a fiber array (FA) 110, a grating 120, an optical switching engine 130, and a wavefront modulation module 200. The fiber array 110 includes an optical input port and an optical output port. The light beam enters through the optical input port, passes sequentially through the wavefront modulation module 200 and the grating 120, and is then transmitted to the optical switching engine 130. After switching by the optical switching engine 130, the beam returns and is output from the optical output port.

[0042] The wavefront modulation module is used to shape and output the light beam from the optical input port of the fiber array 110, and then reshape the returning light beam before transmitting it to the output port of the fiber array 110. In some embodiments, the wavefront modulation module can also be referred to as an optical shaping module.

[0043] In some embodiments of this application, to improve the integration of the wavelength selective switch 100, the wavelength selective switch 100 may further include a transparent body 140. Both the wavefront modulation module 200 and the grating 120 are connected to the transparent body 140. Thus, at least a portion of the optical path between the wavefront modulation module 200 and the grating 120 is within the transparent body 140. The wavefront modulation module 200, the grating 120, and the transparent body 140 do not require hermetic packaging, reducing packaging difficulty and cost. Furthermore, integrating the wavefront modulation module 200 and the grating 120 onto the transparent body 140 can increase the integration of the wavelength selective switch 100 and reduce its size.

[0044] In some embodiments of this application, the grating 120 is etched and formed on the transparent body 140. In other words, the grating 120 and the transparent body 140 are integrally molded. The grating 120 and the transparent body 140 do not need to be connected by other components. In some embodiments, the grating 120 and the transparent body 140 can be connected by optical adhesive or the like.

[0045] In some embodiments of this application, the optical switching engine 130 and the transparent body 140 are connected. For example, the optical switching engine 130 is connected to the transparent body 140 via optical adhesive or the like. Thus, the optical switching engine 130, the grating 120, and the wavefront modulation module 200 are all connected to the transparent body 140. The optical paths between the optical switching engine 130, the grating 120, and the wavefront modulation module 200 are all within the transparent body 140. The optical switching engine 130 and the transparent body 140 do not require hermetic packaging, reducing packaging difficulty and cost. Furthermore, the integration density of the wavelength selective switch 100 can be increased, and its size reduced.

[0046] The material of the transparent body 140 is not limited in this application embodiment. For example, the material of the transparent body 140 may include glass or resin.

[0047] For example, the optical switching engine 130 may include liquid crystal on silicon (LCOS).

[0048] It is understood that in some embodiments, the transparent body 140 is not necessary, and the fiber array 110, grating 120, optical switching engine 130, and wavefront modulation module 200 can be set independently.

[0049] Figure 3b This is a schematic diagram of another wavelength selection switch 100. Figure 3b and Figure 3a The difference is that the wavelength selection switch 100 does not include the transparent body 140.

[0050] Figure 3b In the example, the fiber array 110, optical switching engine 130, grating 120, and wavefront modulation module 200 are set up independently. The optical paths between the fiber array 110, optical switching engine 130, grating 120, and wavefront modulation module 200 are in free space. Figure 3b In this design, the fiber array 110, the optical switching engine 130, the grating 120, and the wavefront modulation module 200 are hermetically sealed. Figure 3b The transparent body 140 is not included, and the number of optical devices is reduced.

[0051] Figure 3bDepending on the optical path requirements, the wavelength selection switch 100 may also include a curved reflector 150 and a spherical mirror 160. The curved reflector 150 and the spherical mirror 160 are used for shaping the light transmitted from the grating 120 to the wavefront modulation module 200.

[0052] Figure 4 This is a schematic diagram of the wavefront control module 200 provided in an embodiment of this application. Please refer to... Figure 4 The wavefront control module 200 includes a base layer 210, a filler layer 220, and multiple metasurface optical elements 230. The base layer 210 and the filler layer 220 are stacked. The multiple metasurface optical elements 230 are located between the base layer 210 and the filler layer 220.

[0053] In the embodiments of this application, for ease of description, the thickness direction of the wavefront control module 200 is defined as the z-direction, and the base layer 210 and the filling layer 220 are stacked along the z-direction.

[0054] A metasurface optical element 230 and a fiber array 110 (e.g.) Figure 3a (As shown) corresponds to one port. This application embodiment does not limit the number of metasurface optical elements 230, which can be set according to the number of ports of the fiber array 110. It is understood that the number of metasurface optical elements 230 can be greater than or equal to the number of ports of the fiber array 110.

[0055] This application does not limit the dimension k of the metasurface optical element 230 along the z-direction. It can be set according to the beam shaping requirements. In this application's embodiments, the dimension k of each metasurface optical element 230 along the z-direction is the same. During the formation of the metasurface optical element 230, each metasurface optical element 230 can be processed at the same depth along the z-direction. This facilitates the formation of multiple metasurface optical elements 230 in the same process, simplifying the manufacturing process.

[0056] Figure 5 A schematic diagram of the structure of multiple metasurface optical elements 230 and the base layer 210 provided in the embodiments of this application. Please refer to... Figure 5 On the base layer 210, the arrangement path of multiple metasurface optical elements 230 is arc-shaped. In other words, the multiple metasurface optical elements 230 are arranged in an arc. If multiple beams are transmitted to the wavefront control module 200 (such as...) Figure 4 As shown), the light spots of multiple beams are arranged in an arc shape, and the multiple metasurface optical elements 230 arranged in an arc shape can couple the multiple beams of light arranged in an arc shape well. For example, the beams are selected by the wavelength selection switch 100 (e.g., ...). Figure 3a During transmission in the fiber array (as shown), due to the different positions of each input port, the beam from each input port is transmitted to the grating 120 (as shown). Figure 3aThe incident angles of the beams at different input ports are different. Different incident angles result in different equivalent periods of the grating. The beams transmitted from each input port to different output ports exhibit different positional shifts in the dispersion direction after being shaped by the grating 120. These multiple beams with positional shifts in the dispersion direction are received by the wavefront modulation module 200. Since the multiple metasurface optical elements 230 are arranged in an arc shape, energy loss caused by the beam shifts in the dispersion direction after being shaped by the grating 120 can be reduced, thus improving the coupling efficiency of the wavefront modulation module 200.

[0057] The aforementioned dispersion direction is also known as the wavelength direction, and it is perpendicular to the optical axis of the beam. The aforementioned "optical axis" refers to the centerline of the beam (also called the beam column), or the axis of symmetry of the optical system. The beam should not exhibit any changes in its optical properties when rotating around this axis.

[0058] Understandable, Figure 5 This is merely to illustrate the relative positional relationship of multiple metasurface optical elements 230, and is not intended to limit the size of the metasurface optical elements 230 or the ratio of the distance between two adjacent metasurface optical elements 230. For example, Figure 5 The parameters such as the radii and radius of curvature of the arrangement paths of multiple metasurface optical elements 230 are restricted.

[0059] In some embodiments of this application, the arrangement path of the plurality of metasurface optical elements 230 is symmetrical. In other words, the arrangement path of the plurality of metasurface optical elements 230 is a symmetrical arc. For example, the plurality of metasurface optical elements 230 can better couple the light beam to the fiber array 110 (e.g., Figure 3a (As shown).

[0060] like Figure 5 As shown, in some embodiments of this application, multiple metasurface optical elements 230 are symmetrical about the symmetry axis L. Along the extension direction of the symmetry axis L, the distance between two adjacent metasurface optical elements 230 is greater than or equal to 1 μm. Thus, the port position compensation effect for two adjacent metasurface optical elements 230 is better, and the coupling efficiency is improved.

[0061] The aforementioned "distance between two adjacent metasurface optical elements 230" refers to the difference in distance between the geometric centers of two adjacent metasurface optical elements 230 and their deviation from the axis of symmetry L.

[0062] For example, Figure 5In the diagram, along the extension direction of the symmetry axis L, the distance between metasurface optical elements 230a and 230b is d1. The distance between metasurface optical elements 230b and 230c is d2. The distance between metasurface optical elements 230c and 230d is d3. Metasurface optical elements 230a, 230b, and 230c are arranged sequentially. d1 is greater than or equal to 1 μm; for example, d1 can be 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, etc. Similarly, d2 is greater than or equal to 1 μm; d3 is greater than or equal to 1 μm. The values ​​of d2 and d3 can be the same as d1 mentioned above, and will not be exemplified here.

[0063] This application does not limit the size relationship of d1, d2, and d3. Based on the arc-shaped arrangement of metasurface optical elements 230a, 230b, and 230c, d1 can be greater than, less than, or equal to d2, d2 can be greater than, less than, or equal to d3, and d2 can be greater than, less than, or equal to d3.

[0064] It is understood that in some embodiments of this application, the distance (d1) between two adjacent metasurface optical elements 230 along the extension direction of the axis of symmetry L may also be less than 1 μm.

[0065] In the embodiments of this application, a first direction is defined as perpendicular to the axis of symmetry L. Figure 5 The m-direction is the first direction. In this embodiment, the distance between two adjacent metasurface optical elements 230 along the first direction is not limited. In some embodiments, the distance between two adjacent metasurface optical elements 230 along the m-direction is greater than or equal to 50 μm, thus effectively ensuring the diffraction efficiency of the metasurface optical elements.

[0066] Figure 5 In the m-direction, the distance between metasurface optical element 230a and metasurface optical element 230b is h1. The distance between metasurface optical element 230b and metasurface optical element 230c is h2. The distance between metasurface optical element 230c and metasurface optical element 230d is h3. Exemplarily, h1 is greater than or equal to 50 μm, for example, h1 can be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 100 μm, 110 μm, or 120 μm, etc.

[0067] In some embodiments of this application, the axis of symmetry L is parallel to the dispersion direction of the wavefront modulation module 200. When the grating 120 (e.g. Figure 3aThe multiple beams transmitted (as shown) exhibit positional offsets in the dispersion direction. Since the arrangement paths of the multiple metasurface optical elements 230 are symmetrical about the axis of symmetry L, which is parallel to the dispersion direction, the beams can be better coupled to the metasurface optical elements 230, thereby improving the coupling efficiency of the wavefront modulation module 200.

[0068] For example, the aforementioned "symmetry axis L is parallel to the dispersion direction of the wavefront control module 200" allows for the existence of manufacturing and assembly errors. For instance, the angle between the symmetry axis L and the dispersion direction of the wavefront control module 200 can be -8° to 8°. The angle between the symmetry axis L and the dispersion direction of the wavefront control module 200 can be 0°, ±1°, ±2°, ±3°, ±4°, ±5°, ±6°, ±7°, or ±8°, etc.

[0069] As described above, in the embodiment where the wavelength selective switch 100 includes a transparent body 140, the filler layer 220 or the base layer 210 is connected to the transparent body 140.

[0070] In some embodiments, the filler layer 220 and the transparent body 140 are connected. For example, the filler layer 220 and the transparent body 140 are connected by optical adhesive. The filler layer 220 and the transparent body 140 have the same refractive index. Thus, during the transmission of the light beam between the filler layer 220 and the transparent body 140, the change in the direction of light transmission is small or almost negligible, and the loss during light beam penetration is minimal.

[0071] It is understood that the fact that the filling layer 220 and the transparent body 140 have the same refractive index does not limit the difference between their refractive indices to zero. In some embodiments, the difference between the refractive indices of the filling layer 220 and the transparent body 140 is less than or equal to 0.1, for example, the difference between their refractive indices is 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, or 0.1.

[0072] In some embodiments of this application, the surface of the filler layer 220 away from the base layer 210 is planar. This allows for better adhesion between the filler layer 220 and the transparent body 140, preventing gaps between the filler layer 220 and the transparent body 140 from affecting the shape of the light beam.

[0073] In some embodiments, the substrate 210 and the transparent body 140 are connected. For example, the substrate 210 and the transparent body 140 are connected by optical adhesive. The substrate 210 and the transparent body 140 have the same refractive index. Thus, during the transmission of light beams between the substrate 210 and the transparent body 140, the direction of light transmission changes little or almost nothing, and no additional interface loss is generated.

[0074] The refractive index of the base layer 210 and the transparent body 140 is the same as that of the aforementioned filling layer 220 and the transparent body 140, and will not be repeated here.

[0075] In some embodiments of this application, the surface of the base layer 210 away from the filler layer 220 is planar. The base layer 210 and the transparent body 140 can fit together better.

[0076] This application does not limit the material of the filler layer 220. Exemplarily, the material of the filler layer 220 includes a non-metallic dielectric material with low optical loss, such as silicon dioxide or polymethyl methacrylate.

[0077] This application does not limit the material of the base layer 210. Exemplarily, the material of the base layer 210 includes a non-metallic dielectric material with low refractive index and low optical loss. For example, the material of the base layer 210 includes silicon oxide.

[0078] This application does not limit the material of the metasurface optical element 230. Exemplarily, the material of the metasurface optical element 230 includes a non-metallic dielectric material with a high refractive index, such as at least one of silicon, titanium dioxide, silicon nitride, or gallium nitride.

[0079] The embodiments of this application do not limit the formation method of the metasurface optical element 230. For example, a pre-film is deposited on the base layer 210 and the pre-film is etched to form the metasurface optical element 230.

[0080] This application embodiment does not limit the shape of the filling layer 220 and the base layer 210. For example, the filling layer 220 can be a cuboid, cylindrical, hexagonal prism, pentagonal prism, or irregularly shaped layer structure. Similarly, the filling layer 220 can be a cuboid, cylindrical, hexagonal prism, pentagonal prism, or irregularly shaped layer structure.

[0081] The metasurface optical element 230 has a beam shaping function, that is, after the beam transmitted to the metasurface optical element 230 is shaped by the metasurface optical element 230, the size or shape of the beam spot is adjusted.

[0082] The embodiments of this application do not impose any restrictions on the structure of the metasurface optical element 230.

[0083] Figure 6 This is a schematic diagram of the structure of a metasurface optical element 230 provided in an embodiment of this application. Please refer to... Figure 6 The metasurface optical element 230 includes a plurality of arrayed nanopillars 231. This application does not limit the material constituting the nanopillars 231, and the material constituting the nanopillars 231 can be silicon (Si).

[0084] For example, the width of each nanopillar 231 is less than or equal to the wavelength of the optical signal corresponding to the received array unit, and the height of the nanopillar 231 is also less than or equal to the wavelength of the optical signal corresponding to the received array unit; the size of the nanopillar 231 is on the nanometer scale.

[0085] Multiple nanopillars 231 are arranged in columns, with each column containing multiple nanopillars 231. The spacing between the nanopillars 231 in adjacent columns is the same.

[0086] The size and structure of each nanopillar 231 in the same column of nanopillars 231 may be different or the same, and there is no limitation here. The size and structure of each nanopillar 231 in the same row of nanopillars 231 may be different or the same, and there is no limitation here.

[0087] Once the arrangement of the first column of nanopillars 231 is determined, each subsequent column of nanopillars 231 can be considered as a copy of the arrangement of the first column, and arranged sequentially. In other words, the nanopillars 231 are distributed in an array.

[0088] In the embodiments of this application, the structure of each nanopillar 231 can be set according to the phase amplitude shaping requirements of the metasurface optical element 230 for the beam.

[0089] Figure 6 In the example, the width of each column of nanopillars 231 in the row direction is n1. The center distance between two adjacent nanopillars 231 in the same column is n1. n1 is less than the minimum wavelength in the working band.

[0090] Among them, n1 can also be referred to as the period of the metasurface optical element 230.

[0091] In some embodiments, the vertical projection of the nanopillars 231 onto the substrate 210 is a centrally symmetric pattern. Thus, if only the polarization state of the beam transmitted to the metasurface optical element 230 is changed, the metasurface optical element 230 consistently shapes the beam, meaning the metasurface optical element 230 exhibits polarization-independent characteristics. For example, two beams with different polarization states are... Figure 6 After the metasurface optical element 230 is shaped, the two beams have the same spot shape and size.

[0092] Figure 6 In the example, the vertical projection of the nanopillar 231 onto the base layer 210 is circular. The aforementioned "vertical projection of the nanopillar 231 onto the base layer 210" refers to the projection of the nanopillar 231 onto the base layer 210 in the direction perpendicular to the base layer 210, i.e., the thickness direction of the base layer 210.

[0093] The phase response of the metasurface optical element 230 covers a range >2π. The phase of the metasurface optical element 230 can be adjusted by changing the size of the nanopillars 231.

[0094] For example, Figure 7 The graph shows the relationship between the size and response phase of the cylindrical nanopillar 231, and the period of the nanopillar ( Figure 6 In the figure, n1) is 890nm, the thickness of the nanopillar is 250nm, the material of the nanopillar is silicon, and the material of the base layer is silicon oxide. Figure 7 Suitable for nanopillars 231 whose vertical projection on the base layer 210 is circular. Figure 7 The horizontal axis represents the diameter of the nanopillar 231, one vertical axis represents the phase, and the other vertical axis represents the transmittance. Figure 7 The midline s1 represents the transmission efficiency of nanopillars of different sizes, and the line s2 represents the phase response of nanopillars of different sizes. From... Figure 7 It can be seen that there is a corresponding relationship between the size of the nanopillars and the response of the metasurface optical elements. While maintaining high diffraction efficiency, changing the size of the structure can achieve phase modulation requirements greater than 2π. Based on this, the size of the nanopillars 231 can be set according to the amplitude and phase modulation requirements.

[0095] It is understood that in some embodiments, the vertical projection of the nanopillars 231 onto the base layer 210 can be other centrally symmetric shapes. For example, it can be a square. The dimensions of the nanopillars 231 are the side length of this square.

[0096] It is understood that in other embodiments of this application, the vertical projection of the nanopillars 231 onto the base layer 210 can be a non-centrosymmetric figure.

[0097] Figure 8 A schematic diagram of another metasurface optical element 230 provided in an embodiment of this application. Please refer to... Figure 8 , Figure 8 and Figure 6 The difference lies in the shape of the nanopillars 231; for the rest, please refer to the previous section. Figure 6 The description.

[0098] In some embodiments, the vertical projection of the nanopillars 231 onto the base layer 210 is a non-centrosymmetric pattern.

[0099] Thus, when beams of different polarization directions are transmitted to the nanopillar 231, the nanopillar 231 modulates the phase and amplitude of the beam differently, thereby achieving an independent beam size shaping effect.

[0100] For example, when two beams with perpendicular polarization directions are transmitted to the metasurface optical element 230, the metasurface optical element 230 exhibits independent spot shaping effect on the two beams, and the metasurface optical element 230 exhibits polarization-dependent characteristics.

[0101] For example, Figure 8 In this embodiment, the vertical projection of the nanopillars 231 onto the substrate 210 is rectangular. The dimensions of the nanopillars 231 are the length of the long side and the length of the short side of the rectangle. In some embodiments, the vertical projection of the nanopillars 231 onto the substrate 210 can be elliptical. The dimensions of the aforementioned nanopillars 231 are the length of the major axis and the length of the minor axis of the ellipse.

[0102] As described above, the wavefront modulation module 200 includes multiple metasurface optical elements 230. These metasurface optical elements 230 may have identical or different structures. For example, each metasurface optical element 230 may have the following structure: Figure 6 As shown, or, the structure of each metasurface optical element 230 is as follows: Figure 8 As shown. Alternatively, the structure of a portion of the metasurface optical elements 230 is as follows: Figure 6 As shown, the structure of a portion of the metasurface optical elements 230 is as follows: Figure 8 As shown.

[0103] Figure 9 This is an exploded structural diagram of the wavefront modulation module 200 and the fiber array 110 provided in the embodiments of this application. Please refer to... Figure 9 The fiber array 110 includes multiple optical fibers 111, one of which is coupled to a metasurface optical element 230 of the wavefront modulation module 200. The aforementioned optical input or output port is located on the optical fiber 111. The multiple optical fibers 111 are arranged in an arc shape. In other words, the vertical projection of the multiple optical fibers 111 onto the substrate 210 is arc-shaped. This allows for better alignment between the optical fibers 111 and the metasurface optical element 230, and better coupling of the beam output from the wavefront modulation module 200 into the optical fiber 111.

[0104] Figure 9 The dashed lines representing the metasurface optical element 230 are for illustrating the position of the metasurface optical element 230 within the filling layer 220, and do not restrict the metasurface optical element 230 to be located on the surface of the filling layer 220.

[0105] The number of optical fibers 111 in this application embodiment is not limited and can be set according to the number of ports of the fiber array 110. It is understood that in the embodiments of this application, the number of optical fibers 111 and the number of metasurface optical elements 230 can be the same. Alternatively, the number of metasurface optical elements 230 can be greater than the number of optical fibers 111. In embodiments where the number of metasurface optical elements 230 can be greater than the number of optical fibers 111, a portion of the metasurface optical elements 230 and optical fibers 111 are connected in a one-to-one correspondence. The remaining number of metasurface optical elements 230 may not be coupled to the optical fibers 111.

[0106] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A wavefront control module, characterized in that, The wavefront modulation module includes: grassroots level; A filler layer, wherein the base layer and the filler layer are stacked together; and Multiple metasurface optical elements, all of which are located between the base layer and the filler layer; On the surface of the base layer, the plurality of metasurface optical elements are arranged in an arc shape.

2. The wavefront control module according to claim 1, characterized in that, The arrangement path of the multiple metasurface optical elements is a symmetrical pattern.

3. The wavefront control module according to claim 2, characterized in that, The symmetrical pattern is symmetrical about the axis of symmetry, and the distance between two adjacent metasurface optical elements along the extension direction of the axis of symmetry is greater than or equal to 1 μm.

4. The wavefront control module according to claim 3, characterized in that, The axis of symmetry is parallel to the dispersion direction of the wavefront modulation module.

5. The wavefront control module according to any one of claims 2-4, characterized in that, Along the first direction, the distance between two adjacent metasurface optical elements is greater than or equal to 50 μm, and the first direction is perpendicular to the axis of symmetry of the symmetrical pattern.

6. The wavefront control module according to any one of claims 1-5, characterized in that, The surface of the filler layer away from the base layer is planar.

7. The wavefront control module according to any one of claims 1-6, characterized in that, Each of the metasurface optical elements comprises an array of multiple nanopillars, the vertical projection of which onto the substrate is a centrally symmetric pattern.

8. The wavefront control module according to any one of claims 1-7, characterized in that, The base material includes silicon dioxide.

9. The wavefront control module according to any one of claims 1-8, characterized in that, The material of the metasurface optical element includes at least one of silicon, titanium dioxide, silicon nitride, or gallium nitride.

10. The wavefront control module according to any one of claims 1-9, characterized in that, The filler layer is made of materials including silicon dioxide or polymethyl methacrylate.

11. A wavelength selective switch, characterized in that, The wavelength selection switch includes: grating; The wavefront modulation module according to any one of claims 1-10; the wavefront modulation module is used to shape the beam and transmit the beam to the grating, and the wavefront modulation module is also used to receive the beam from the grating in the reverse direction.

12. The wavelength selective switch according to claim 11, characterized in that, The wavelength selection switch further includes a transparent body, and both the grating and the wavefront modulation module are connected to the transparent body.

13. The wavelength selective switch according to claim 12, characterized in that, The base layer is bonded to the transparent body, and the base layer and the transparent body have the same refractive index; Alternatively, the filling layer is bonded to the transparent body, and the filling layer and the transparent body have the same refractive index.

14. An optical network device, characterized in that, The optical network device includes an optical fiber and a wavelength selection switch as described in any one of claims 11-13; the optical fiber is connected to the wavelength selection switch.

Images