Micromirror array and related apparatus and system

Abstract

Embodiments of the present application disclose a micromirror array and a related apparatus and system. A plurality of gratings having different size parameters are etched in the micromirror array, and incident light is diffracted by the plurality of gratings having different size parameters to form light of a plurality of diffraction orders, wherein zero-order diffracted light is reflected light, and the diffraction directions of higher-order diffracted light are different from that of the zero-order diffracted light. In a port switching process, only the zero-order diffracted light is transmitted to a non-target port due to reflection, causing crosstalk, and the higher-order diffracted light is not transmitted to the non-target port. Because the plurality of gratings having different size parameters are designed, the degree of freedom in adjusting and controlling the energy of the higher-order diffracted light is high. The present application is more applicable to broad spectra and is more conducive to adjusting and controlling light energy to the higher-order diffracted light, so as to reduce the zero-order diffracted light, thereby effectively reducing crosstalk generated in the port switching process.

Description

A micromirror array and related devices and systems

[0001] This application claims priority to Chinese Patent Application No. 202510338015.7, filed with the State Intellectual Property Office of China on March 19, 2025, entitled “A Micromirror Array and Related Devices and Systems”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical transmission, and more particularly to a micromirror array and related devices and systems. Background Technology

[0003] Micro-electro-mechanical systems (MEMS) micromirrors are devices that utilize MEMS technology to deflect or modulate light. Compared to traditional mechanical micromirrors, MEMS micromirrors offer advantages such as small size, low cost, ease of integration, and high reliability. MEMS micromirrors and their array devices are widely used in optical communication. MEMS micromirror array chips typically contain multiple micromirror units. The reflective surfaces of these units are generally made of silicon, which has a certain reflectivity for communication wavelengths, such as the 1310nm band.

[0004] MEMS micromirrors can be applied in optical communication scenarios that require high precision in micromirror rotation and high fill ratio, such as optical cross-connects (OXC) or wavelength selective switches (WSS), to switch communication data from one fiber optic port to another. During port switching, light travels from the original port to the target port as the MEMS micromirror unit rotates. However, upon passing through the silicon material, the light is reflected into ports adjacent to both the original and target ports, causing crosstalk in the communication data. Summary of the Invention

[0005] This application provides a micromirror array and related devices and systems. The micromirror array is etched with a variety of gratings with different size parameters, which makes the energy control of higher order diffracted light more flexible, more suitable for a wide spectrum, and more conducive to controlling the energy of light to higher order diffracted light, thereby reducing zero-order diffracted light and effectively reducing crosstalk generated during port switching.

[0006] In a first aspect, this application provides a micromirror array, comprising a substrate, a first grating, a second grating, and multiple micromirror units, wherein the first grating, the second grating, and the multiple micromirror units are located on the substrate. The first grating includes multiple first protrusion structures, and the second grating includes multiple second protrusion structures. At least one of the first and second gratings partially exists between any two adjacent micromirror units, meaning that during the switching of incident light from one micromirror to another, the light spot will inevitably illuminate at least one partial structure of the grating. The grating is an optical device composed of parallel slits of equal width and spacing; the portion between two adjacent parallel slits in the grating is called a protrusion structure, and the partial structure of the grating illuminated by the light spot includes the protrusion structures and / or slits of the grating.

[0007] The first grating and the second grating satisfy at least one of the following conditions:

[0008] In the first direction, the width of the first protrusion structure is different from the width of the second protrusion structure. The first direction is the distribution direction of the multiple first protrusion structures and the distribution direction of the multiple second protrusion structures.

[0009] In the second direction, the height of the first protrusion structure is different from the height of the second protrusion structure, and the second direction is perpendicular to the substrate;

[0010] In the first direction, the distance between every two adjacent first protrusions in the first grating is different from the distance between every two adjacent second protrusions in the second grating.

[0011] In this embodiment, incident light undergoes diffraction after passing through the first and second gratings to form light of multiple diffraction orders. The zeroth-order diffracted light is reflected, while the diffraction directions of higher-order diffracted light differ from those of the zeroth-order diffracted light. During the switching process from incident on the first micromirror unit to incident on the second micromirror unit, the incident light can pass through both the first and second gratings. The zeroth-order diffracted light will cause crosstalk due to reflection and propagation towards non-target ports. Higher-order diffracted light may not propagate towards non-target ports, or if it does, the coupling efficiency is low. Because multiple gratings with different size parameters are designed, the energy control of higher-order diffracted light has greater freedom, making it more suitable for a wider spectrum and more conducive to controlling the energy of light towards higher-order diffracted light, thus reducing the amount of zeroth-order diffracted light and effectively reducing crosstalk generated during port switching.

[0012] In some possible implementations, there is a first protrusion structure and a second protrusion structure between any two adjacent micromirror units in the plurality of micromirror units, so that when the incident light switches between any two micromirror units, the light spot can cover the protrusion structure of the two gratings, which makes it easier to control the energy of the light to the higher order diffraction light and helps to reduce the zero order diffraction light.

[0013] In some possible implementations, a second protrusion structure is included between every two adjacent first protrusion structures, and a first protrusion structure is included between every two adjacent second protrusion structures. This interleaved arrangement effectively ensures that there is a protrusion structure for each type of grating between any two adjacent micromirror units in the micromirror array, so as to cope with port crosstalk that may be caused during the switching of incident light between any two micromirror units.

[0014] In some possible implementations, the micromirror array further includes a third grating located on the substrate, the third grating comprising a plurality of third protrusions distributed along a first direction. At least one corresponding dimensional parameter of any two of the first, second, and third gratings is different.

[0015] The dimensional parameters of the first grating include at least one of the following: the width of the first protrusion in the first direction, the height of the first protrusion in the second direction, and the distance between any two adjacent first protrusions in the first grating in the first direction. The dimensional parameters of the second grating include at least one of the following: the width of the second protrusion in the first direction, the height of the second protrusion in the second direction, and the distance between any two adjacent second protrusions in the second grating in the first direction. The dimensional parameters of the third grating include at least one of the following: the width of the third protrusion in the first direction, the height of the third protrusion in the second direction, and the distance between any two adjacent third protrusions in the third grating in the first direction.

[0016] It should be understood that the difference in at least one corresponding dimensional parameter between any two gratings refers to the difference in value of at least one dimensional parameter of the same type between any two gratings. Essentially, it's about distinguishing whether two gratings are different by comparing at least one dimensional parameter of the same type between any two gratings. The three types of dimensional parameters for gratings described above are: the width of the grating's protrusions in the first direction, the height of the grating's protrusions in the second direction, and the distance between any two adjacent protrusions in the grating in the first direction.

[0017] In some possible implementations, any two adjacent micromirror units in the plurality of micromirror units include a first protrusion structure, a second protrusion structure and a third protrusion structure, so that during the switching of incident light between any two micromirror units, the light spot can cover the protrusion structure of the three gratings, which makes it easier to control the energy of the light to the higher order diffraction light and is more conducive to reducing the zero order diffraction light.

[0018] In some possible implementations, the first grating further includes a plurality of first protrusions distributed along a third direction, and the second grating further includes a plurality of second protrusions distributed along a third direction, wherein the first direction, the second direction, and the third direction are perpendicular to each other. It should be understood that a one-dimensional grating can only reduce zero-order diffraction light in one dimension, while the two-dimensional grating provided in this implementation can reduce zero-order diffraction light in two dimensions, thereby more effectively reducing crosstalk generated in various port switching scenarios.

[0019] In some possible implementations, the micromirror array further includes an antireflection coating. The antireflection coating is located between the layer containing the first and second gratings and the substrate, effectively placing the first and second gratings on top of the antireflection coating, simplifying the fabrication process. Alternatively, the layer containing the first and second gratings can be located between the antireflection coating and the substrate, effectively placing the antireflection coating on top of the first and second gratings, which provides better protection for the grating formation. The antireflection coating increases the transmittance of incident light and reduces reflectivity, effectively reducing reflected light from the area between the micromirror units, thereby reducing crosstalk during port switching.

[0020] In some possible implementations, the antireflection coating includes a multilayer sub-antireflection coating, wherein at least two of the sub-antireflection coatings have different refractive indices, which is beneficial to further increase the transmittance of incident light and reduce the reflectance.

[0021] In some possible implementations, the first grating has curvature, and / or the second grating has curvature. It should be understood that for a grating with curvature, the grating can achieve a grating-converging effect by adjusting the phase of the incident light, so as to focus the diffracted light to other non-port directions, which is more conducive to reducing crosstalk generated during port switching.

[0022] In some possible implementations, a thin film is disposed on the substrate, and the first and second gratings are formed on the thin film by etching. The substrate and the thin film are made of different materials. This is equivalent to etching the gratings on the thin film rather than on the substrate surface. By setting the thickness of the thin film, it is beneficial to accurately define the height of the grating protrusions in the Z direction, that is, to accurately define the thickness of the grating.

[0023] In some possible implementations, the micromirror array satisfies the following constraints:

[0024] Among them, h si θ represents the height of either the first or second protruding structure in the second direction, λ represents the wavelength of the incident light, and θ represents the height of the first or second protruding structure in the second direction. iThis represents the incident angle of the incident light onto the micromirror array, where m is an odd number. The micromirror array satisfies this constraint, which can effectively reduce the energy proportion of the zero-order diffracted light formed by light incident on the grating. For example, it can make the energy of the zero-order diffracted light account for less than 1% of the total energy of the diffracted light, which is more conducive to reducing crosstalk generated during port switching.

[0025] In some possible implementations, the micromirror array satisfies the following constraints:

[0026] Where P represents the period length of the first or second grating, θ i θ represents the incident angle of the incident light onto the micromirror array. sysmax θ represents the maximum optical scanning angle of the micromirror unit. sysmin The minimum optical scanning angle of the micromirror unit is represented by λ, where λ represents the wavelength of the incident light, and n... max This represents the order of the maximum diffraction energy generated by the incident light after passing through the first and second gratings. Micromirror arrays satisfy this constraint, effectively preventing higher-order diffracted light formed by light incident on the gratings from propagating to the ports of the fiber array, and further reducing crosstalk generated during port switching.

[0027] In some possible implementations, the micromirror array satisfies the following constraint: 0.1 <W1 / P1<0.8 0.1<W2 / P2<0.8

[0028] Where W1 represents the width of the first protrusion in the first direction, P1 represents the period length of the first grating, W2 represents the width of the second protrusion in the first direction, and P2 represents the period length of the second grating. The micromirror array satisfies this constraint, effectively suppressing zero-order diffraction light formed by light incident on the grating, and further reducing crosstalk generated during port switching.

[0029] In some possible implementations, in the first direction, the width of the first protrusion structure is greater than 0.1 μm and less than 20 μm, and the width of the second protrusion structure is greater than 0.1 μm and less than 20 μm.

[0030] In some possible implementations, in the first direction, the distance between any two adjacent first protrusions in the first grating is greater than 1 μm and less than the distance between any two adjacent micromirror units, and the distance between any two adjacent second protrusions in the second grating is greater than 1 μm and less than the distance between any two adjacent micromirror units.

[0031] In some possible implementations, in the second direction, the height of the first protrusion structure is greater than 0.1 μm and less than 5 μm, and the height of the second protrusion structure is greater than 0.1 μm and less than 5 μm.

[0032] Secondly, this application provides a micromirror array, which includes a substrate, an antireflection film, and multiple micromirror units, all located on the substrate. An antireflection film exists between any two adjacent micromirror units. The antireflection film increases the transmittance of incident light and reduces its reflectivity, effectively reducing reflected light from the region between the micromirror units and thus reducing crosstalk during port switching.

[0033] In some possible implementations, the antireflection coating includes a multilayer sub-antireflection coating, wherein at least two of the sub-antireflection coatings have different refractive indices, which is beneficial to further increase the transmittance of incident light and reduce the reflectance.

[0034] Thirdly, this application provides a micromirror array, which includes a substrate, a recessed structure, and multiple micromirror units, wherein the recessed structure and the multiple micromirror units are located on the substrate. A recessed structure exists between any two adjacent micromirror units. The recessed structure between the micromirror units can change the reflection angle of the incident light, causing the reflected light to propagate in other non-port directions, thereby reducing crosstalk generated during port switching.

[0035] Fourthly, this application provides an optical cross-connect (OXC) device. The OXC device includes a first fiber array, a second fiber array, a first micromirror array, and a second micromirror array. At least one of the first and second micromirror arrays is a micromirror array as described in any of the embodiments of the first to third aspects. The first fiber array is used to couple at least one optical path to the first micromirror array. At least one micromirror element in the first micromirror array is used to rotate to reflect at least one optical path to the second micromirror array. At least one micromirror element in the second micromirror array is used to rotate to couple at least one optical path to the second fiber array.

[0036] Fifthly, this application provides a data center comprising multiple computing nodes and at least one OXC device as described in the fourth aspect. Each of the multiple computing nodes is connected to the OXC device.

[0037] In some possible implementations, the data center also includes an electrical switch, with at least one of the multiple compute nodes connected to the OXC device via the electrical switch.

[0038] Sixthly, this application provides a lidar system, which includes a light source, a beam shaping device, a light receiving device, a detector, and a micromirror array as described in any of the embodiments of the first to third aspects. The beam shaping device is used to shape the light emitted by the light source. The micromirror array is used to adjust the deflection direction of the beam-shaped light so that the beam-shaped light is transmitted to a target object, and the light reflected by the target object is transmitted to the detector via the light receiving device. The detector is used to detect the light reflected by the target object.

[0039] In a seventh aspect, this application provides a laser projection device, which includes a light source, a screen, and a micromirror array as described in any of the embodiments of the first to third aspects. The micromirror array is used to adjust the deflection direction of the light emitted by the light source to project the light onto the screen.

[0040] The micromirror array provided in this application is etched with a first grating and a second grating. The first grating includes multiple first protrusion structures, and the second grating includes multiple second protrusion structures. Any two adjacent micromirror units are separated by both first and second protrusion structures. At least one dimensional parameter of the first grating and the second grating is different. It should be understood that incident light undergoes diffraction after passing through the first and second gratings to form light of multiple diffraction orders. The zeroth-order diffracted light is reflected light, and the diffraction direction of higher-order diffracted light differs from that of the zeroth-order diffracted light. During the process of switching light from incident on the first micromirror unit to incident on the second micromirror unit, the incident light can pass through both the first and second gratings. The zeroth-order diffracted light will cause crosstalk due to reflection and propagation towards non-target ports. Higher-order diffracted light may not propagate towards non-target ports or may propagate towards non-target ports but with low coupling efficiency. By designing gratings with different size parameters, the energy control of higher-order diffracted light is more flexible, making it more suitable for a wide spectrum. It is also more conducive to controlling the energy of light to higher-order diffracted light to reduce zero-order diffracted light, thereby effectively reducing crosstalk generated during port switching. Attached Figure Description

[0041] Figure 1 is a schematic diagram of a micromirror array structure;

[0042] Figure 2 is a schematic diagram of an OXC device;

[0043] Figure 3 is a schematic diagram of the optical path for port switching in an OXC device;

[0044] Figure 4 is a schematic diagram of a micromirror array in an embodiment of this application;

[0045] Figure 5 is a partial side view of a micromirror array in an embodiment of this application;

[0046] Figure 6 is another partial side view of the micromirror array in an embodiment of this application;

[0047] Figure 7 is another partial side view of the micromirror array in an embodiment of this application;

[0048] Figure 8 is another partial side view of the micromirror array in an embodiment of this application;

[0049] Figure 9 is another partial side view of the micromirror array in an embodiment of this application;

[0050] Figure 10 is a partial top view of a micromirror array in an embodiment of this application;

[0051] Figure 11 is another partial top view of the micromirror array in an embodiment of this application;

[0052] Figure 12 is another partial top view of the micromirror array in an embodiment of this application;

[0053] Figure 13(a) is another partial side view of the micromirror array in an embodiment of this application;

[0054] Figure 13(b) is another partial side view of the micromirror array in an embodiment of this application;

[0055] Figure 13(c) is another partial side view of the micromirror array in an embodiment of this application;

[0056] Figure 14 is another partial side view of the micromirror array in an embodiment of this application;

[0057] Figure 15 is another partial side view of the micromirror array in an embodiment of this application;

[0058] Figure 16 is another partial side view of the micromirror array in an embodiment of this application;

[0059] Figure 17 is a top view of the grating in an embodiment of this application;

[0060] Figure 18 is a schematic diagram showing the variation of insertion loss with the etching depth of the grating;

[0061] Figure 19 is another partial side view of the micromirror array in an embodiment of this application;

[0062] Figure 20 is another partial side view of the micromirror array in an embodiment of this application;

[0063] Figure 21 is a schematic diagram showing the reflectivity of zero-order diffracted light as a function of wavelength;

[0064] Figure 22 is a schematic diagram showing the variation of reflectivity of zero-order diffracted light with incident angle;

[0065] Figure 23 is a schematic diagram showing the variation of the reflectivity of zero-order diffracted light with the refractive index of the grating material;

[0066] Figure 24 is another schematic diagram showing the variation of the reflectivity of zero-order diffracted light with the refractive index of the grating material;

[0067] Figure 25 is a schematic diagram of a data center;

[0068] Figure 26 is a schematic diagram of a lidar structure;

[0069] Figure 27 is a schematic diagram of a laser projection device. Detailed Implementation

[0070] This application provides a micromirror array and related devices and systems. The micromirror array is etched with a variety of gratings with different size parameters, which makes the energy control of higher order diffracted light more flexible, more suitable for a wide spectrum, and more conducive to controlling the energy of light to higher order diffracted light, thereby reducing zero-order diffracted light and effectively reducing crosstalk generated during port switching.

[0071] To facilitate understanding of the embodiments of this application, the following points are made:

[0072] First, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0073] Second, "at least one" means one or more, and "more than one" means two or more (including two). "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can mean: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b, and c. Here, a, b, and c can be single or multiple.

[0074] Third, the terms "first," "second," and various numerical designations (e.g., #1, #2) are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. For example, they can be used to distinguish different indication information.

[0075] Fourth, the terms “comprising” and “having” and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.

[0076] Fifth, if an element or layer is referred to as being "on" another element or layer, then it can be directly on the other element or layer, or there may be intermediate elements or layers. To facilitate the description of the relationship between one element and another shown in the figures, spatial relational terms such as "below," "under," "below," "above," "on top of," etc., are used herein. It should be understood that spatial relational terms are intended to include different orientations of the device in application or operation other than those described in the figures. For example, if the device in the figures is flipped, an element described as "below other elements or features" or "below other elements or features" will be oriented "above other elements or features." Thus, the term "below" can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial descriptors herein are understood accordingly.

[0077] Figure 1 is a schematic diagram of a micromirror array. As shown in Figure 1, multiple micromirror units share the same substrate and are arranged in rows and columns to form a micromirror array. These micromirror units can also be called micromirrors or micro-electro-mechanical-system (MEMS) micromirrors. Each micromirror unit in the array is independently controlled, and the rotation direction and angle of the mirror in each unit can be flexibly adjusted according to actual needs. Each pair of adjacent micromirror units is typically separated by silicon material to prevent airflow disturbance during rotation and to create electric field shielding, reducing electrical crosstalk between adjacent units.

[0078] In some possible implementations, the micromirror array further includes a driving array, which may specifically be a complementary metal-oxide-semiconductor (CMOS) array. Specifically, the driving array controls the electrodes in each micromirror unit to drive the mirror surface in each micromirror unit to rotate. It should be understood that the driving array is typically monolithically integrated with the micromirror array.

[0079] Figure 2 is a schematic diagram of an OXC device. As shown in Figure 2, the optical cross-connect (OXC) device includes a first fiber array A1, a first micromirror array A2, a second micromirror array A3, and a second fiber array A4. The first micromirror array A2 and the second micromirror array A3 can be the micromirror arrays described in Figure 1 above. Specifically, the first fiber array A1 is used to couple at least one optical path to at least one micromirror unit in the first micromirror array A2. At least one micromirror unit in the first micromirror array A2 rotates to reflect at least one optical path to at least one micromirror unit in the second micromirror array A3. At least one micromirror unit in the second micromirror array A3 rotates to couple at least one optical path to the second fiber array A4. In this way, the optical path carrying the service can be switched between different ports.

[0080] Figure 3 is a schematic diagram of the optical path for port switching in an OXC device. As shown in Figure 3, light from a micromirror unit on the first micromirror array A2 is incident on a micromirror unit on the second micromirror array A3. As the micromirror unit on the first micromirror array A2 rotates, the light from that micromirror unit on the first micromirror array A2 is incident on another micromirror unit on the second micromirror array A3, causing the light to switch from the original port of the second fiber array A4 to the target port of the second fiber array A4, thereby realizing port switching. Because the material between the micromirror units on the second micromirror array A3 (such as silicon) has a certain reflectivity for light of certain wavelengths (such as 1310nm), the light is reflected by the material between the micromirror units to other ports of the second fiber array A4 during the port switching process, as shown by the dashed line in Figure 3, thus causing crosstalk in the communication data.

[0081] To address the potential crosstalk issue during port switching, this application provides a micromirror array. Multiple gratings with varying dimensional parameters are etched within the micromirror array. Incident light undergoes diffraction upon passing through these gratings, forming multiple diffraction orders. The zeroth-order diffracted light is reflected, while higher-order diffracted light exhibits different diffraction directions. During port switching, the zeroth-order diffracted light can be reflected and propagated towards non-target ports, causing crosstalk. Higher-order diffracted light may not propagate to non-target ports, or its coupling efficiency may be low. The use of multiple gratings with varying dimensional parameters allows for greater freedom in energy control of higher-order diffracted light, making it more suitable for a wider spectrum and facilitating energy manipulation towards higher-order diffracted light, thus reducing the impact of zeroth-order diffracted light and effectively minimizing crosstalk during port switching.

[0082] The micromirror array provided in the embodiments of this application will be described in detail below.

[0083] Figure 4 is a schematic diagram of a micromirror array according to an embodiment of this application. As shown in Figure 4, the micromirror array includes a substrate 10 and a plurality of micromirror units 100 located on the substrate 10. The plurality of micromirror units 100 are arranged in the row and column directions to form a micromirror array. For example, in this embodiment of the application, the rows and columns on the micromirror array are defined as the X direction and the Y direction, respectively, and the direction perpendicular to the substrate 10 is defined as the Z direction.

[0084] Multiple gratings are also etched on the substrate 10, with different gratings having different dimensional parameters. A grating is an optical device composed of parallel slits of equal width and spacing. For ease of explanation, in this embodiment, the portion between two adjacent parallel slits in the grating is referred to as a protrusion structure. At least one partial structure of a grating exists between any two adjacent micromirror units. That is, during the process of incident light switching from one micromirror to another, the light spot will inevitably illuminate at least one partial structure of the grating. The partial structure of the grating illuminated by the light spot includes the protrusion structure and / or slits of the grating.

[0085] In a grating, multiple slits are arranged in parallel along one direction, which can also be referred to as the distribution direction of the slits in the grating or the distribution direction of the protrusions in the grating. The embodiments of this application do not limit the distribution direction of the slits in the grating. As shown in Figure 4, the multiple slits in the grating can be distributed along the X direction; or, the multiple slits in the grating can be distributed along the Y direction; or, the multiple slits in the grating can be distributed along any other direction within the plane.

[0086] In one example, a raised structure for each grating exists between any two adjacent micromirror units in the micromirror array. Taking Figure 4 as an example, two types of gratings with different size parameters are etched on the substrate 10, and these two types of gratings have raised structures between any two adjacent micromirror units in the micromirror array. This allows the incident light spot to cover the raised structures of multiple gratings during the switching between any two micromirror units, facilitating the control of light energy onto higher-order diffracted light and reducing zero-order diffracted light.

[0087] For ease of explanation, the following description uses the example of multiple slits in a grating distributed along the X-direction. In the X-direction, the dimensional parameters of the grating include the width of the slits and the distance between two adjacent slits. Specifically, the width of a slit is the distance between two adjacent raised structures, and the distance between two adjacent slits is the width of the raised structure between two adjacent slits. In the Z-direction, the dimensional parameters of the grating include the height of the raised structures. Therefore, different gratings have different at least one of these dimensional parameters, which will be described below with reference to specific embodiments.

[0088] Figure 5 is a partial side view of a micromirror array in an embodiment of this application. As shown in Figure 5, the substrate 10 of the micromirror array also includes a mirror layer 20 and a reflective layer 30, with the mirror layer 20 located between the substrate 10 and the reflective layer 30. For the micromirror unit 100, the reflective layer 30 can be a reflective film deposited on the mirror layer 20, meaning that a portion of the structure of the micromirror unit 100 belongs to the mirror layer 20, and another portion belongs to the reflective layer. For example, a cavity is also provided on the substrate 10, and a portion of the structure of the micromirror unit 100 located in the mirror layer 20 is suspended above the cavity and can rotate to drive another portion of the structure located in the reflective layer 30 to rotate accordingly, thereby adjusting the reflection direction of the incident light after passing through the reflective layer 30.

[0089] It should be noted that each micromirror unit 100 in the micromirror array adopts a similar structural design. In order to facilitate the demonstration of the specific structure of the grating, Figure 5 will not show more micromirror units 100. The structure of the micromirror unit 100 in the subsequent embodiments is also similar to that in Figure 5. The main difference lies in the structure of the grating. The structure of the micromirror unit 100 will not be described in detail in the subsequent embodiments.

[0090] In one example, each grating in the micromirror array is etched onto the mirror layer 20. In the Z direction, the height of the grating protrusion structure can be the same as or different from the height of the portion of the micromirror unit 100 located in the mirror layer 20; no specific limitation is made here.

[0091] As shown in Figure 5, the micromirror array includes grating 1 and grating 2. In the X direction, the width of the protrusion 1 in grating 1 is W1, and the width of the protrusion 2 in grating 2 is W2; W1 and W2 are different. In the Z direction, the height of the protrusion 1 in grating 1 and the height of the protrusion 2 in grating 2 are both H. It can be seen that in the embodiment shown in Figure 5, the difference in dimensional parameters between grating 1 and grating 2 is reflected in the difference between W1 and W2.

[0092] In one example, as shown in Figure 5, the protrusions 1 in grating 1 and 2 in grating 2 are interleaved. That is, in grating 1, every two adjacent protrusions 1 are separated by one protrusion 2, and in grating 2, every two adjacent protrusions 2 are separated by one protrusion 1. In this example, the difference in dimensional parameters between grating 1 and grating 2 is also reflected in the fact that the distance G1 between every two adjacent protrusions 1 in grating 1 is different from the distance G2 between every two adjacent protrusions 2 in grating 2. This interleaved arrangement effectively ensures that each type of grating protrusion exists between any two adjacent micromirror units in the micromirror array, thus addressing potential port crosstalk that may occur during the switching of incident light between any two micromirror units.

[0093] Figure 6 is another partial side view of the micromirror array in an embodiment of this application. Unlike the embodiment shown in Figure 5, as shown in Figure 6, in the X direction, the width W1 of the protrusion 1 in grating 1 is the same as the width W2 of the protrusion 2 in grating 2, and the distance G1 between every two adjacent protrusions 1 in grating 1 is the same as the distance G2 between every two adjacent protrusions 2 in grating 2. In the Z direction, the height H1 of the protrusion 1 in grating 1 is different from the height H2 of the protrusion 2 in grating 2. It can be seen that in the embodiment shown in Figure 6, the difference in the dimensional parameters of grating 1 and grating 2 is reflected in the difference between H1 and H2.

[0094] Figure 7 is another partial side view of the micromirror array in an embodiment of this application. Unlike the embodiments shown in Figures 5 and 6, as shown in Figure 7, in the X direction, the width W1 of the protrusion 1 in grating 1 is the same as the width W2 of the protrusion 2 in grating 2. In the Z direction, the height H1 of the protrusion 1 in grating 1 is the same as the height H2 of the protrusion 2 in grating 2. In the X direction, the distance G1 between every two adjacent protrusions 1 in grating 1 is different from the distance G2 between every two adjacent protrusions 2 in grating 2. It can be seen that in the embodiment shown in Figure 7, the difference in the dimensional parameters of grating 1 and grating 2 is reflected in the difference between G1 and G2.

[0095] In one example, as shown in Figure 7, the arrangement of grating 1 and grating 2 can also differ from the interleaved arrangement shown in Figures 5 and 6. For example, in grating 1, there are two protrusions 2 between every two adjacent protrusions 1. It should be understood that the arrangement of grating 1 and grating 2 also depends on the respective size parameters of grating 1 and grating 2. Provided that grating 1 and grating 2 have at least one different size parameter, and that there are protrusions of each type of grating between any two adjacent micromirror units in the micromirror array, this application does not limit the arrangement of grating 1 and grating 2.

[0096] The embodiments shown in Figures 5 to 7 above illustrate that grating 1 and grating 2 may have three different dimensional parameters: W1 and W2 are different, H1 and H2 are different, and G1 and G2 are different. In practical applications, grating 1 and grating 2 only need to satisfy at least one of these different dimensional parameters. Furthermore, arbitrary combinations can be made to obtain more embodiments; that is, grating 1 and grating 2 can also have two different dimensional parameters, or grating 1 and grating 2 can also have three different dimensional parameters. These will not be described in detail here.

[0097] It should be noted that the embodiments of this application do not limit the specific number of gratings with different size parameters included in the micromirror array. The following is an embodiment of the micromirror array including 3 gratings with different size parameters, based on the embodiment shown in Figure 5 above.

[0098] Figure 8 is another partial side view of the micromirror array in an embodiment of this application. Based on the structure shown in Figure 5, as shown in Figure 8, the micromirror array also includes a grating 3. In the X direction, the width of the protrusion structure 3 in the grating 3 is W3, and W1, W2, and W3 are all different. In the Z direction, the height of the protrusion structure 1 in the grating 1, the height of the protrusion structure 2 in the grating 2, and the height of the protrusion structure 3 in the grating 3 are all H.

[0099] It should be noted that for micromirror arrays comprising three or more types of gratings, it is sufficient that any two gratings differ in at least one corresponding dimensional parameter. It should be understood that "at least one corresponding dimensional parameter differing between any two gratings" means that the values ​​of at least one dimensional parameter of the same type differ between the two gratings. Essentially, it distinguishes whether two gratings are different by comparing at least one dimensional parameter of the same type. The three types of dimensional parameters for gratings described above are: the width of the grating's protrusions in the first direction, the height of the grating's protrusions in the second direction, and the distance between any two adjacent protrusions in the grating in the first direction.

[0100] Furthermore, the differences in the dimensional parameters of the two gratings may manifest in different aspects. For example, the difference in dimensional parameters between grating 1 and grating 2 is reflected in the difference between W1 and W2. For example, the difference in dimensional parameters between grating 2 and grating 3 is reflected in the difference between H1 and H2. For example, the difference in dimensional parameters between grating 1 and grating 3 is reflected in the difference between W1 and W3 and the difference between H1 and H3. Based on this, arbitrary combinations can be made to obtain more embodiments, which will not be described one by one here.

[0101] Figure 9 is another partial side view of the micromirror array in an embodiment of this application. As shown in Figure 9, in one example, a thin film 200 is disposed on the substrate 10, and the grating in the micromirror array is formed on the thin film 200 by etching. For example, the grating shown in Figure 5 is etched on the thin film 200. The material of the thin film 200 is different from the material of the substrate 10. For example, the substrate 10 is silicon, while the material of the thin film 200 can be silicon oxide or silicon nitride. Essentially, the grating is not etched on the silicon surface, but on the thin film. By setting the thickness of the thin film, it is beneficial to accurately define the height of the grating protrusion structure in the Z direction, that is, to accurately define the thickness of the grating.

[0102] The embodiments described above all depict a micromirror array using a one-dimensional grating structure, where the parallel slits (or protrusions) in the grating are distributed only along the X-direction. In some possible scenarios, a two-dimensional grating structure can also be used in the micromirror array, where the grating includes parallel slits (or protrusions) distributed along both the X and Y directions. It should be understood that a one-dimensional grating can only reduce zero-order diffraction light in one dimension, while a two-dimensional grating can reduce zero-order diffraction light in two dimensions, thereby more effectively reducing crosstalk generated in various port switching scenarios.

[0103] For various two-dimensional gratings in a micromirror array, different two-dimensional gratings are characterized by at least one difference in size parameter in at least one dimension. The following describes some possible embodiments.

[0104] Figure 10 is a partial top view of a micromirror array in an embodiment of this application. As shown in Figure 10, multiple protrusions 1 in grating 1 are distributed along the X and Y directions, respectively, and multiple protrusions 2 in grating 2 are distributed along the X and Y directions, respectively. That is, both grating 1 and grating 2 are two-dimensional gratings. In the X direction, the width W1 of the protrusion 1 in grating 1 is different from the width W2 of the protrusion 2 in grating 2. In the Y direction, the width of the protrusion 1 in grating 1 and the width of the protrusion 2 in grating 2 are both L. It can be seen that in the embodiment shown in Figure 10, the difference in dimensional parameters between grating 1 and grating 2 is only reflected in one dimension, that is, W1 and W2 are different.

[0105] Figure 11 is another partial top view of the micromirror array in an embodiment of this application. Unlike the embodiment shown in Figure 10, as shown in Figure 11, in addition to the difference in the X direction between the width W1 of the protrusion 1 in grating 1 and the width W2 of the protrusion 2 in grating 2, the width L1 of the protrusion 1 in grating 1 and the width L2 of the protrusion 2 in grating 2 are also different in the Y direction. It can be seen that in the embodiment shown in Figure 11, the difference in the dimensional parameters of grating 1 and grating 2 is reflected in two dimensions, namely, W1 and W2 are different, and L1 and L2 are different.

[0106] It should be noted that for 2D grating 1 and 2D grating 2, there may be differences in at least one of the three dimensional parameters described in the embodiments shown in Figures 5 to 7 in any dimension. In practical applications, 2D grating 1 and 2 only need to satisfy the requirement of at least one difference in at least one dimensional parameter in at least one dimension. Based on this, any combination can be made to obtain more embodiments, which will not be described one by one here.

[0107] The embodiments described above all depict micromirror arrays with multiple gratings (e.g., grating 1 and grating 2) in one dimension (X direction), meaning multiple sets of parallel slits (or protrusions) of equal width and spacing in one dimension (X direction). This application does not limit the number of sets of parallel slits (or protrusions) of equal width and spacing in the other dimension (Y direction) of the micromirror array. For example, as shown in Figure 10, the micromirror array has one set of parallel slits (or protrusions) of equal width and spacing in the other dimension (Y direction). Another example is that the micromirror array has multiple sets of parallel slits (or protrusions) of equal width and spacing in the other dimension (Y direction). In other words, if a two-dimensional grating is used in the micromirror array, at least one dimension of the two-dimensional grating can have multiple sets of parallel slits (or protrusions) of equal width and spacing. A possible embodiment will be described below.

[0108] Figure 12 is another partial top view of the micromirror array in an embodiment of this application. As shown in Figure 12, grating 1 and grating 2 are both two-dimensional gratings. In the X direction, grating 1 has a set of protrusions 1 with a width of W1 and a spacing of G1, and grating 2 has a set of protrusions 2 with a width of W2 and a spacing of G2. In the Y direction, grating 1 has a set of protrusions 1-1 with a width of L-1 and a spacing of G-1, and grating 1 also has a set of protrusions 1-2 with a width of L-2 and a spacing of G-2; similarly, grating 2 has a set of protrusions 2-1 with a width of L-1 and a spacing of G-1, and grating 2 also has a set of protrusions 2-2 with a width of L-2 and a spacing of G-2.

[0109] Figure 13(a) is another partial side view of the micromirror array in an embodiment of this application. Figure 13(b) is another partial side view of the micromirror array in an embodiment of this application. Figure 13(c) is another partial side view of the micromirror array in an embodiment of this application. As shown in Figures 13(a) to 13(c), the micromirror array further includes an antireflection film 300, which is used to increase the transmittance of incident light and reduce the reflectivity. This is equivalent to reducing the reflected light formed when light is incident on the area between the micromirror units, thereby reducing crosstalk generated during port switching.

[0110] In one example, as shown in Figure 13(a), the antireflection film 300 is located between the layer containing the grating (including grating 1 and grating 2) and the substrate 10, which is equivalent to the grating being located above the antireflection film 300, making the process implementation simpler.

[0111] In one example, as shown in Figure 13(b), the layer containing the grating (including grating 1 and grating 2) is located between the antireflection film 300 and the substrate 10, which is equivalent to the antireflection film 300 being located above the grating, which is beneficial for protecting the grating formation. The antireflection film 300 is formed by depositing a film on the basis of filling the slits of the grating.

[0112] In one example, as shown in Figure 13(c), the layer containing the gratings (including grating 1 and grating 2) is located between the antireflection film 300 and the substrate 10. This means that the antireflection film 300 is located above the gratings, which is beneficial for protecting the grating formation. The difference from the structure shown in Figure 13(b) is that the antireflection film in Figure 13(c) is formed by coating the surface of the grating. This means that the antireflection film has the same shape as the grating surface, and it is not necessary to fill the slits of the grating.

[0113] In one possible implementation, the antireflective coating 300 includes a multilayer sub-antireflective coating, wherein at least two sub-antireflective coatings have different refractive indices, i.e., at least two thin film materials with different refractive indices are stacked alternately to form the antireflective coating 300.

[0114] It should be noted that the film material and size of the antireflection coating 300 are related to the wavelength of the incident light. For example, for incident light in the vicinity of 1310 nm, the film material of the antireflection coating 300 can be a stack of tantalum oxide and silicon oxide; or, the film material of the antireflection coating 300 can be a stack of aluminum oxide and silicon; or, the film material of the antireflection coating 300 can be a stack of magnesium oxide and silicon.

[0115] Figure 14 is another partial side view of the micromirror array in an embodiment of this application. Unlike the structures shown in Figures 13(a) to 13(c), as shown in Figure 14, in one possible implementation, the micromirror array may not include a grating, but instead uses an antireflection film 300 instead of a grating. That is, the antireflection film 300 is located on the substrate 10, and there is an antireflection film 300 between any two adjacent micromirror units in the micromirror array. By increasing the transmittance of incident light and reducing the reflectivity by using the antireflection film 300, the reflected light formed in the area between the micromirror units can be reduced, thereby reducing crosstalk generated during port switching.

[0116] Figure 15 is another partial side view of the micromirror array in an embodiment of this application. As shown in Figure 15, in one possible implementation, the micromirror array may not include a grating, but instead uses a recessed structure 400 instead of a grating. That is, a recessed structure 400 is provided on the substrate between any two adjacent micromirror units in the micromirror array. When light is incident on the recessed structure 400 between the micromirror units, it can change the reflection angle of the incident light, causing the reflected light to propagate in other non-port directions, thereby reducing crosstalk generated during port switching. The embodiments of this application do not limit the specific shape of the recessed structure 400. Taking Figure 15 as an example, the cross-sectional shape of the recessed structure 400 is an inverted triangle.

[0117] Figure 16 is another partial side view of the micromirror array in an embodiment of this application. As shown in Figure 16, a metal thin film 500 may also be covered on the surfaces of grating 1 and grating 2 in the micromirror array. The metal thin film 500 is used to reduce the transmittance of incident light, thereby minimizing the impact of incident light passing through grating 1 and grating 2 on other components inside the micromirror array.

[0118] Figure 17 is a top view of the grating in an embodiment of this application. For any of the gratings described in the above embodiments, this application does not limit whether the grating has curvature. Figure 17 shows gratings with and without curvature. It should be understood that for gratings with curvature, the grating can achieve beam converging by adjusting the phase of the incident light, so as to focus the diffracted light to other non-port directions, which is more conducive to reducing crosstalk generated during port switching.

[0119] Based on the various embodiments of the micromirror array described above, in order to minimize the zero-order diffraction light formed by light incident on the grating and to avoid the transmission of higher-order diffraction light formed by light incident on the grating to the port of the fiber array as much as possible, some further constraints on the size parameters of the grating are provided below.

[0120] In one example, the micromirror array satisfies the following first constraint:

[0121] Among them, h si λ represents the thickness or etching depth of any grating in the micromirror array, λ represents the wavelength of the incident light, and θ represents the depth of the grating. i This represents the incident angle of the incident light onto the micromirror array, where m is an odd number. It should be understood that, taking the embodiment shown in Figure 5 as an example, h... si h can represent the height of the protrusion 1 in the Z direction of grating 1. si It can also represent the height of the protrusion structure 2 in the Z direction of the grating 2. Optionally, m = 1. The micromirror array satisfies this first constraint, which can effectively reduce the energy proportion of the zero-order diffracted light formed by light incident on the grating. For example, it can make the energy of the zero-order diffracted light account for less than 1% of the energy of all diffracted light, which is more conducive to reducing crosstalk generated during port switching.

[0122] Figure 18 is a schematic diagram illustrating the variation of insertion loss with the etching depth of the grating. As shown in Figure 18, the horizontal axis represents the thickness or etching depth of the grating (in nm), and the vertical axis represents the insertion loss (dB). Figure 18 shows the reflectance of the zero-order diffracted light formed after incident light passes through the grating at three different incident angles: 15deg, 25deg, and 30deg. Figure 18 demonstrates which specific values ​​of grating thickness or etching depth better suppress the reflectance of the zero-order diffracted light.

[0123] In one example, taking a micromirror array comprising grating 1 and grating 2, the micromirror array satisfies the following second constraint: 0.1 <W1 / P1<0.8 0.1<W2 / P2<0.8

[0124] Where W1 represents the width of protrusion 1 of grating 1 in the X direction, P1 represents the period length of grating 1, W2 represents the width of protrusion 2 of grating 2 in the X direction, and P2 represents the period length of grating 2. It should be understood that the period length of the grating can be defined as the distance between the boundary of one protrusion in the grating and the boundary of an adjacent protrusion; the boundaries of these two adjacent protrusions refer to the boundaries located on the same side of the protrusions. Therefore, the period length of the grating is different from the distance between two adjacent protrusions in the grating; the period length of the grating is equal to the sum of the width of the grating and the distance between two adjacent protrusions in the grating. The micromirror array satisfies this second constraint, which can effectively suppress the zero-order diffraction light formed by light incident on the grating, and is more conducive to reducing crosstalk generated during port switching.

[0125] Figure 19 is another partial side view of the micromirror array in an embodiment of this application. Based on the embodiment shown in Figure 5, as shown in Figure 19, the period length P1 of grating 1 is W1 + G1, and the period length P2 of grating 2 is W2 + G2. G1 represents the distance between every two adjacent protrusions 1 in grating 1, and G2 represents the distance between every two adjacent protrusions 2 in grating 2.

[0126] In one example, the micromirror array satisfies the following third constraint:

[0127] Where P represents the period length of the grating in the micromirror array (e.g., the period length P1 of grating 1 or the period length P2 of grating 2), θ i θ represents the incident angle of the incident light onto the micromirror array. sysmax θ represents the maximum optical scanning angle of the micromirror unit. sysmin The minimum optical scanning angle of the micromirror unit is represented by λ, where λ represents the wavelength of the incident light, and n... max n represents the order of the maximum diffraction energy produced by the incident light after passing through the grating in the micromirror array. max This can also be understood as the diffraction order of the highest-order diffracted light generated after the incident light passes through the grating in the micromirror array. It should be understood that, taking the embodiment shown in Figure 20 as an example, P can represent the period length of grating 1, and P can also represent the period length of grating 2. The micromirror array satisfies this third constraint, which can effectively prevent the high-order diffracted light formed by the incident light from the grating from being transmitted to the port of the fiber array, and is more conducive to reducing crosstalk generated during port switching.

[0128] Figure 20 is another partial side view of the micromirror array in an embodiment of this application. As shown in Figure 20, the mechanical scanning angle of the micromirror unit is denoted as θ. m The mechanical scanning angle of a micromirror unit can also be understood as the rotation angle of the micromirror unit. The optical scanning angle of a micromirror unit is twice the mechanical scanning angle, that is, the optical scanning angle of the micromirror unit is 2θ. m Taking Figure 2 above as an example, the optical scanning angle of each micromirror unit on the first micromirror array A2 should satisfy the requirement that the emitted beam covers all micromirror units on the second micromirror array A3.

[0129] Based on the various embodiments of the micromirror array described above, in order to minimize the zero-order diffraction light formed by light incident on the grating and to minimize the transmission of higher-order diffraction light formed by light incident on the grating to the port of the fiber array, specific numerical ranges of some grating size parameters are provided below, which are beneficial to reducing the energy proportion of the zero-order diffraction light formed by light incident on the grating.

[0130] In one example, the width of the protrusion structure of any grating in the micromirror array in the X direction is denoted as W, where 0.1 μm < W < 20 μm. Taking a micromirror array including grating 1 and grating 2 as an example, the width of the protrusion structure 1 of grating 1 in the X direction is W1 = 1.9 μm, and the width of the protrusion structure 2 of grating 2 in the X direction is W2 = 2.4 μm.

[0131] In one example, the distance between any two adjacent protrusions in any grating of a micromirror array is denoted as G, where 1 μm < G, and G is less than the distance between any two adjacent micromirror units in the micromirror array. Taking a micromirror array including grating 1 and grating 2 as an example, the distance between any two adjacent protrusions 1 in grating 1 is G1 = 7 μm, and the distance between any two adjacent protrusions 2 in grating 2 is G2 = 6.5 μm.

[0132] In one example, the height of the protrusion of any grating in the micromirror array in the Z direction is denoted as H, where 0.1 μm < H < 5 μm. For example, H = 370 nm.

[0133] In one example, taking Figure 5 as an example, the protrusion structure 1 in grating 1 and the protrusion structure 2 in grating 2 are interleaved. The distance between any protrusion structure 1 and the adjacent protrusion structure 2 is greater than 0.1 μm. For example, the distance between any protrusion structure 1 and the adjacent protrusion structure 2 is 2.4 μm.

[0134] The implementation effects of the embodiments of this application will be demonstrated below with some experimental simulation diagrams.

[0135] Figure 21 is a schematic diagram showing the reflectivity of zero-order diffracted light as a function of wavelength. As shown in Figure 21, the horizontal axis represents the wavelength of the incident light (in nm), and the vertical axis represents the reflectivity of the zero-order diffracted light. As can be seen from Figure 21, the grating in the micromirror array provided in this embodiment can effectively reduce the reflectivity of incident light at certain wavelengths (such as 1310 nm).

[0136] Figure 22 is a schematic diagram showing the variation of the reflectivity of the zero-order diffracted light with the incident angle. As shown in Figure 22, the horizontal axis represents the incident angle of the incident light (unit: deg), and the vertical axis represents the reflectivity of the zero-order diffracted light. As can be seen from Figure 22, the grating in the micromirror array provided in this application embodiment can effectively reduce the reflectivity of the incident light for various incident angles.

[0137] It should be noted that the grating in the micromirror array provided in this application mainly achieves the extinction effect by modulating the optical path difference or phase caused by the reflected light through the convex structure or slit. Therefore, this application embodiment is not sensitive to the refractive index of the grating material itself.

[0138] Figure 23 is a schematic diagram illustrating the variation of the reflectivity of zero-order diffracted light with the refractive index of the grating material. As shown in Figure 23, the horizontal axis represents the refractive index of the grating material, and the vertical axis represents the reflectivity of the zero-order diffracted light. Figure 23 is based on an example where the grating is etched onto a substrate, meaning the grating uses the same material as the substrate.

[0139] Figure 24 is another schematic diagram showing the variation of the reflectivity of the zero-order diffracted light with the refractive index of the grating material. As shown in Figure 24, the horizontal axis represents the refractive index of the grating material, and the vertical axis represents the reflectivity of the zero-order diffracted light. Figure 24 is based on an example of a grating formed by etching on a thin film material, specifically using the thin film material described in the embodiment shown in Figure 9.

[0140] It should be noted that the micromirror array provided in this application embodiment can be applied to the OXC device described in Figure 2 above. The OXC device described in Figure 2 above can be applied to various scenarios, and this application embodiment does not limit the specific application. The following description takes the application of the OXC device in a data center as an example.

[0141] Figure 25 is a schematic diagram of a data center. As shown in Figure 25, the data center includes multiple computing nodes and at least one OXC device. Each of the multiple computing nodes is connected to the OXC device, and signals transmitted between any two computing nodes pass through the OXC device. In one example, the data center also includes an electrical switch, and at least one computing node is connected to the OXC device through the electrical switch. In another example, at least one computing node is connected to another OXC device through one of the OXC devices.

[0142] It should be noted that the micromirror array provided in this application embodiment can be applied not only to OXC devices, but also to other devices; the specific application embodiment is not limited thereto. The following description uses the application of the micromirror array to lidar and laser projection devices as examples.

[0143] Figure 26 is a schematic diagram of a lidar structure. As shown in Figure 26, the lidar includes: a light source B1, a beam shaping device B2, a micromirror array B3, a light receiving device B4, and a detector B5. Specifically, the beam shaping device B2 is used to shape the light emitted by the light source B1. The micromirror array B3 is used to adjust the deflection direction of the shaped light so that the shaped light is transmitted to the target object. The light reflected by the target object is transmitted to the detector B5 through the light receiving device B4. The detector B5 is used to detect the light reflected by the target object.

[0144] It should be noted that lidar is a radar system that uses emitted laser beams to detect the position, velocity, and other characteristics of targets. It boasts high range, angular, and velocity resolution, strong anti-interference capabilities, and can operate around the clock, independent of external lighting conditions or the radiation characteristics of the target itself. It is an essential sensing device for future autonomous driving. A lidar system consists of a signal source and a receiving system. Using a laser as the signal source, the laser generates and emits a pulsed laser beam that strikes trees, roads, bridges, and buildings on the ground, causing scattering. A portion of the light wave is reflected back to the lidar receiver and ultimately received. The receiver accurately measures the propagation time of the light pulse from emission to reflection. Given that the speed of light is known, the distance from the lidar to the target point can be calculated based on the propagation time. The radial velocity of the target can be determined by the Doppler frequency shift of the reflected light, or by measuring two or more distances and calculating their rate of change. A lidar system requires a scanning device to scan the surrounding targets. By continuously scanning a target object with pulsed lasers, data on all target points can be obtained. Combined with the laser's height and scanning angle, a precise three-dimensional image of the surrounding environment can be generated. Using micromirror arrays as scanning micromirrors in LiDAR is currently a mainstream approach for solid-state LiDAR and a major application direction. It should be understood that the micromirror array is the core component of LiDAR; its performance directly determines the quality of the scanned projected image. Reducing dynamic deformation and increasing the radius of curvature helps improve the optical performance of the micromirror array, increasing detection range and resolution. Furthermore, if LiDAR is applied to autonomous driving, to meet automotive-grade requirements, the micromirror array must have high reliability and lifespan. Avoiding stress concentration and reducing the support structure, as well as lowering power consumption and torsional stress, all contribute to improving the reliability and lifespan of the micromirror array.

[0145] Figure 27 is a schematic diagram of one structure of a laser projection device. As shown in Figure 27, the laser projection device includes a light source C1, a micromirror array C2, and a screen C3. The micromirror array C2 is used to adjust the deflection direction of the light emitted by the light source C1 to project the light onto the screen C3. In some possible embodiments, the light source C1 includes three lasers that emit red, green, and blue light, respectively. It should be understood that the laser projection device is also sensitive to the dynamic deformation and power consumption of the micromirror array. Reducing dynamic deformation and increasing the radius of curvature helps improve the optical performance of the micromirror array, improves the projection imaging effect, reduces the weight of the support structure and torsional stress, helps reduce the power consumption of the micromirror array, and improves the reliability and lifespan of the micromirror array.

[0146] 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 it. 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; and these 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 micromirror array, characterized in that, The micromirror array includes a substrate, a first grating, a second grating, and multiple micromirror units. The first grating, the second grating, and the multiple micromirror units are located on the substrate. The first grating includes multiple first protrusion structures, and the second grating includes multiple second protrusion structures. In any two adjacent micromirror units, there is a partial structure of at least one of the first grating and the second grating. The first grating and the second grating satisfy at least one of the following conditions: In a first direction, the width of the first protrusion structure is different from the width of the second protrusion structure, and the first direction is the distribution direction of the plurality of first protrusion structures and the distribution direction of the plurality of second protrusion structures; In the second direction, the height of the first protrusion structure is different from the height of the second protrusion structure, and the second direction is perpendicular to the substrate; In the first direction, the distance between every two adjacent first protrusions in the first grating is different from the distance between every two adjacent second protrusions in the second grating.

2. The micromirror array according to claim 1, characterized in that, The first protrusion structure and the second protrusion structure exist between any two adjacent micromirror units in the plurality of micromirror units.

3. The micromirror array according to claim 1 or 2, characterized in that, Each pair of adjacent first protrusions includes one second protrusion, and each pair of adjacent second protrusions includes one first protrusion.

4. The micromirror array according to any one of claims 1 to 3, characterized in that, The micromirror array further includes a third grating located on the substrate. The third grating includes a plurality of third protrusion structures distributed along the first direction. At least one of the size parameters of any two gratings among the first grating, the second grating, and the third grating is different. The dimensional parameters of the first grating include at least one of the width of the first protrusion structure in the first direction, the height of the first protrusion structure in the second direction, and the distance between every two adjacent first protrusion structures in the first grating in the first direction; The dimensional parameters of the second grating include at least one of the following: the width of the second protrusion in the first direction, the height of the second protrusion in the second direction, and the distance between every two adjacent second protrusions in the second grating in the first direction; The dimensional parameters of the third grating include at least one of the width of the third protrusion structure in the first direction, the height of the third protrusion structure in the second direction, and the distance between every two adjacent third protrusion structures in the third grating in the first direction.

5. The micromirror array according to claim 4, characterized in that, The plurality of micromirror units include a first protrusion structure, a second protrusion structure, and a third protrusion structure between any two adjacent micromirror units.

6. The micromirror array according to any one of claims 1 to 5, characterized in that, The first grating further includes a plurality of first protrusion structures distributed along a third direction, and the second grating further includes a plurality of second protrusion structures distributed along the third direction, wherein the first direction, the second direction, and the third direction are perpendicular to each other.

7. The micromirror array according to any one of claims 1 to 6, characterized in that, The micromirror array further includes an antireflective coating; the antireflective coating is located between the layer containing the first grating and the second grating and the substrate, or the layer containing the first grating and the second grating is located between the antireflective coating and the substrate.

8. The micromirror array according to claim 7, characterized in that, The antireflective coating comprises multiple sub-antireflective coatings, wherein at least two sub-antireflective coatings have different refractive indices.

9. The micromirror array according to any one of claims 1 to 8, characterized in that, The first grating has curvature, and / or the second grating has curvature.

10. The micromirror array according to any one of claims 1 to 9, characterized in that, A thin film is disposed on the substrate, and the first grating and the second grating are formed on the thin film by etching. The substrate and the thin film are made of different materials.

11. The micromirror array according to any one of claims 1 to 10, characterized in that, The micromirror array satisfies the following constraints: Among them, h si λ represents the height of either the first or second protruding structure in the second direction, λ represents the wavelength of the incident light, and θ represents the height of either the first or second protruding structure in the second direction. i The incident angle of the incident light onto the micromirror array is m, where m is an odd number.

12. The micromirror array according to any one of claims 1 to 11, characterized in that, The micromirror array satisfies the following constraints: Where P represents the period length of the first grating or the second grating, θ i θ represents the incident angle of the incident light onto the micromirror array. sysmax θ represents the maximum optical scanning angle of the micromirror unit. sysmin λ represents the minimum optical scanning angle of the micromirror unit, λ represents the wavelength of the incident light, and n max This indicates the order of the maximum diffraction energy generated after the incident light passes through the first grating and the second grating.

13. The micromirror array according to any one of claims 1 to 12, characterized in that, The micromirror array satisfies the following constraint: 0.1 <W1 / P1<0.8 0.1<W2 / P2<0.8 Wherein, W1 represents the width of the first protrusion structure in the first direction, P1 represents the period length of the first grating, W2 represents the width of the second protrusion structure in the first direction, and P2 represents the period length of the second grating.

14. The micromirror array according to any one of claims 1 to 13, characterized in that, In the first direction, the width of the first protrusion structure is greater than 0.1 μm and less than 20 μm, and the width of the second protrusion structure is greater than 0.1 μm and less than 20 μm.

15. The micromirror array according to any one of claims 1 to 14, characterized in that, In the first direction, the distance between any two adjacent first protrusions in the first grating is greater than 1 μm and less than the distance between any two adjacent micromirror units, and the distance between any two adjacent second protrusions in the second grating is greater than 1 μm and less than the distance between any two adjacent micromirror units.

16. The micromirror array according to any one of claims 1 to 15, characterized in that, In the second direction, the height of the first protrusion is greater than 0.1 μm and less than 5 μm, and the height of the second protrusion is greater than 0.1 μm and less than 5 μm.

17. An optical cross-connect (OXC) device, characterized in that, The OXC device includes a first fiber array, a second fiber array, a first micromirror array, and a second micromirror array, wherein at least one of the first micromirror array and the second micromirror array is a micromirror array as described in any one of claims 1 to 16. The first fiber array is used to couple at least one optical path to the first micromirror array; At least one micromirror unit in the first micromirror array is used to rotate to reflect the at least one path of light to the second micromirror array; At least one micromirror unit in the second micromirror array is used to rotate to couple the at least one optical path to the second fiber array.

18. A data center, characterized in that, The data center includes multiple computing nodes and at least one OXC device as described in claim 17, wherein each of the multiple computing nodes is connected to the OXC device.

19. The data center according to claim 18, characterized in that, The data center also includes an electrical switch, and at least one of the plurality of computing nodes is connected to the OXC device through the electrical switch.

20. A lidar, characterized in that, The lidar includes a light source, a beam shaping device, a light receiving device, a detector, and a micromirror array as described in any one of claims 1 to 16; The beam shaping device is used to shape the light emitted by the light source. The micromirror array is used to adjust the deflection direction of the beam-shaped light so that the beam-shaped light is transmitted to the target object, and the light reflected by the target object is transmitted to the detector through the light receiving device. The detector is used to detect light reflected by the target object.

21. A laser projection device, characterized in that, The laser projection device includes a light source, a screen, and a micromirror array as described in any one of claims 1 to 16; the micromirror array is used to adjust the deflection direction of the light emitted by the light source so as to project the light onto the screen.

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