Spatial light modulator, self-checking device thereof and light computing device

Abstract

The invention provides a spatial light modulator, a self-checking device thereof and a light computing device, and relates to the technical field of optical modulation.The spatial light modulator comprises an incident waveguide structure, a covering plate, a liquid crystal layer, a substrate and an emergent waveguide structure; the incident waveguide structure is optically coupled with the cover plate and is used for guiding externally incident laser into the cover plate at a preset angle; the covering plate is used for enabling laser to be propagated in the covering plate in a total reflection form; the substrate bears the liquid crystal layer, integrates the driving circuit and is used for applying regulation and control voltage to the liquid crystal layer; the liquid crystal layer is arranged on the lower side of the covering plate and used for conducting phase modulation on the laser transmitted to the liquid crystal layer in a total reflection mode in response to the regulation voltage. And the emergent waveguide structure is optically coupled with the covering plate and is used for guiding the laser modulated by the liquid crystal layer out of the covering plate to a free space. According to the spatial light modulator, efficient spatial modulation and accurate control of the light field are realized, so that the integration and function accuracy of the spatial light modulator in self-inspection and light calculation are improved.

Description

Technical Field

[0001] The present application relates to the field of optical modulation technology, and in particular to a spatial light modulator, a self-test device thereof, and an optical computing device. Background Art

[0002] At present, intersatellite laser communication has gradually become an important development direction of space communication system due to its advantages of high speed, large bandwidth and high confidentiality. Common intersatellite laser communication terminals include Figure 1 As shown, it typically includes a signal transmission module and a receiving module, with operating wavelengths of 1540nm and 1560nm, respectively. During the transmission process, the 1540nm laser generated by the laser is collimated by a lens, then passes through the fast reflector FSM2, the color separator, and the reflector FSM1 in sequence before being emitted in the target direction. During the reception process, the 1560nm laser signal is reflected by FSM1, transmitted through the color separator, reflected by the deflection mirror, and passed through the narrowband filter before being split into two beams by the beam splitter.

[0003] Among them, the optical signal beam splitter module is generally implemented using a 90:10 beam splitter prism: about 90% of the incident light energy is directed to the silicon-based liquid crystal spatial light modulator, and after reflection and focusing by the coupling lens, it is coupled into the single-mode optical fiber to realize communication signal reception; the remaining approximately 10% of the light energy is directed to the tracking camera module, which is used to realize tracking and aiming control between terminals and assist in completing satellite attitude adjustment.

[0004] However, existing spatial light modulators (SLMs) commonly suffer from the following issues: First, their structures often rely on free-space propagation, limiting optical path stability and system integration. Second, in complex space environments, device performance cannot be regularly monitored through human intervention, and performance degradation can severely impact system stability. To address this issue, previous studies have proposed self-check mechanisms to monitor the status of SLMs, but these generally lack highly integrated, real-time responsive designs, failing to meet the requirements of remote, contactless, and autonomous judgment for spaceborne equipment.

[0005] Furthermore, with the rapid development of optical computing technology, the pixel-by-pixel tunability of spatial light modulators is being widely used to construct computational structures such as diffractive neural networks. However, in existing systems, multi-level modulation often relies on multiple discrete components connected in series. This not only complicates the optical path and makes alignment difficult, but also hinders the realization of compact, repeatable modulation spatial optical computing structures.

[0006] Therefore, there is an urgent need to provide a spatial light modulator with high structural integration, low-loss guided mode transmission, and multi-region step-by-step phase modulation, while supporting its self-test function and optical computing function expansion. Summary of the Invention

[0007] In response to the problems in the prior art, embodiments of the present application provide a spatial light modulator, a self-test device thereof, and an optical computing device, which can solve the problems in the prior art.

[0008] In a first aspect, the present application provides a spatial light modulator, comprising: an incident waveguide structure, a cover plate, a liquid crystal layer, a substrate, and an output waveguide structure;

[0009] The incident waveguide structure is optically coupled to the cover plate, and is used to guide externally incident laser light into the cover plate at a preset angle;

[0010] The cover plate is used to allow the laser to propagate in the form of total reflection inside the cover plate;

[0011] The substrate carries the liquid crystal layer and integrates a driving circuit for applying a regulating voltage to the liquid crystal layer;

[0012] The liquid crystal layer is provided on the lower side of the cover plate, and is used for performing phase modulation on the laser light that is totally reflected and propagates to the liquid crystal layer in response to the control voltage;

[0013] The output waveguide structure is optically coupled to the cover plate and is used to guide the laser light modulated by the liquid crystal layer out of the cover plate and into free space.

[0014] Furthermore, the incident waveguide structure adopts an edge coupling design, which is a microprism array or a gradient refractive index lens integrated at one end of the cover plate.

[0015] Furthermore, the output waveguide structure adopts an edge coupling design, and is a microprism array or a gradient refractive index lens symmetrical to the input waveguide structure, which is integrated at the other end of the cover plate.

[0016] Furthermore, the incident waveguide structure adopts a front coupling design, and is an embossed grating, a volume grating or a microprism integrated on the upper surface or the lower surface of the cover plate.

[0017] Furthermore, the output waveguide structure adopts a front coupling design, and is an embossed grating, a volume grating or a microprism integrated on the upper surface or the lower surface of the cover plate.

[0018] Furthermore, the liquid crystal layer is fixed between the cover plate and the substrate by optical adhesive.

[0019] Furthermore, the substrate is a silicon-based substrate, and the driving circuit is a semiconductor transistor array.

[0020] Furthermore, the cover plate is made of glass material, and the light beam reflection points in the cover plate are located at a plurality of preset positions corresponding to a plurality of independent working areas divided on the liquid crystal layer.

[0021] Furthermore, pixel intervals are provided between the multiple independent working areas.

[0022] Furthermore, the preset angle is calculated based on the refractive index of the cover plate and is greater than or equal to the critical angle of the cover plate.

[0023] In a second aspect, the present application provides a spatial light modulator self-test device, comprising: a laser light source, a photodetector, and the spatial light modulator described in any one of the above embodiments;

[0024] The laser light source is arranged on the light-incoming side of the incident waveguide structure, and is used to emit detection laser;

[0025] The incident waveguide structure is used to receive the detection laser and guide the detection laser into the cover plate at a preset angle;

[0026] The cover plate is used to allow the detection laser to propagate in the form of total reflection inside the cover plate;

[0027] The substrate is used to apply a regulating voltage to the liquid crystal layer;

[0028] The liquid crystal layer is used to perform phase modulation on the detection laser light that is totally reflected and propagates to the liquid crystal layer in response to the control voltage;

[0029] The output waveguide structure is used to guide the detection laser modulated by the liquid crystal layer from the cover plate to the free space and guide it to the photodetector;

[0030] The photodetector is arranged on the light-emitting side of the output waveguide structure, and is used to detect the power of the modulated detection laser to determine the working state of the spatial light modulator.

[0031] Furthermore, the light beam reflection points in the cover plate are located at multiple preset positions, corresponding to the multiple independent working areas divided on the liquid crystal layer. Blazed grating patterns are displayed in sequence in the multiple independent working areas, and the reflection angle of the detection laser is changed to perform functional detection on the multiple independent working areas.

[0032] Furthermore, the length of the output waveguide structure from the liquid crystal layer is greater than the length of the input waveguide structure from the liquid crystal layer, so as to enhance the energy difference of the modulated detection laser when the spatial light modulator is in working or non-working state.

[0033] Furthermore, the laser light source is a red light semiconductor laser with a wavelength of 635 nm.

[0034] Furthermore, the photodetector is a silicon-based balanced photodetector.

[0035] In a third aspect, the present application provides an optical computing device, comprising: a laser light source, a digital micromirror, a photodetector, and the spatial light modulator described in any one of the above embodiments;

[0036] The digital micromirror is disposed between the laser light source and the incident waveguide structure, and is used to spatially modulate the incident light emitted by the laser light source to form a light field including information to be calculated, and reflect the light field to the incident waveguide structure;

[0037] The incident waveguide structure is used to receive the incident light modulated by the digital micromirror and guide the incident light into the cover plate at a preset angle;

[0038] The cover plate is used to make the incident light propagate in the form of total reflection inside the cover plate, and the multiple reflection points of the reflection path correspond to the multiple independent working areas divided on the liquid crystal layer;

[0039] The substrate is used to apply an independent control voltage to each working area of ​​the liquid crystal layer;

[0040] The liquid crystal layer is used to perform phase modulation on the incident light region by region when the incident light propagates to each reflection point;

[0041] The output waveguide structure is used to guide the incident light after multi-level phase modulation from the cover plate to free space;

[0042] The photodetector is arranged on the light-emitting side of the output waveguide structure, and is used to output a detection signal representing a light calculation result based on the output light derived from the output waveguide structure.

[0043] The present application provides a spatial light modulator, its self-test device, and optical computing device. The spatial light modulator includes: an incident waveguide structure, a cover plate, a liquid crystal layer, a substrate, and an output waveguide structure. The incident waveguide structure is optically coupled to the cover plate and is used to guide externally incident laser light into the cover plate at a preset angle. The cover plate is used to cause the laser light to propagate within it in the form of total internal reflection. The substrate carries the liquid crystal layer and has an integrated drive circuit for applying a control voltage to the liquid crystal layer. The liquid crystal layer is disposed on the underside of the cover plate and is used to phase-modulate the laser light that has been totally reflected and propagated into the liquid crystal layer in response to the control voltage. The output waveguide structure is optically coupled to the cover plate and is used to guide the laser light modulated by the liquid crystal layer from the cover plate to free space. The spatial light modulator, its self-test device, and optical computing device provided in the present application achieve efficient spatial modulation and precise control of the light field, thereby improving the integration and functional accuracy of the spatial light modulator in self-test and optical computing.

[0044] Among them, through the optical coupling of the incident waveguide structure and the cover plate, the laser is efficiently and stably coupled from free space into the cover plate, effectively avoiding the problems of energy diffusion, high difficulty in collimation and poor anti-interference ability in traditional free space propagation, and improving the compactness of the system and the accuracy of light field control; through the preset angle coupling and satisfying total reflection propagation, it is guaranteed that the laser propagates stably in the form of total reflection in the cover plate, constructing a low-loss, high-fidelity optical transmission path, and providing basic support for multi-level modulation of the light field after multiple reflections; by utilizing the geometric layout of the liquid crystal layer close to the total reflection path, local interferometric phase modulation of the incident light is achieved without interfering with the main transmission The overall structure of the path ensures the spatial resolution and accuracy of the modulation. Through the integrated drive circuit on the substrate, the liquid crystal pixels are finely controlled, which can support independent voltage control of each pixel in the liquid crystal layer, forming a programmable, real-time responsive two-dimensional phase modulation array, so that the spatial light modulator has a high degree of freedom of light field modulation capability, which can adapt to different optical signal processing requirements. Through the coupling of the output waveguide structure with the cover plate, the modulated light is derived, and the incident light after phase modulation is stably emitted from the cover plate into free space, effectively maintaining the light field wavefront structure and energy distribution, and providing controllable, high-quality light output for subsequent optical computing, communication or detection links. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0046] Figure 1 It is a schematic diagram of the structure of an intersatellite laser communication terminal in the prior art;

[0047] Figure 2 is a schematic structural diagram of a spatial light modulator provided in one embodiment of the present application;

[0048] Figure 3 1 is a schematic structural diagram of an incident waveguide structure of a spatial light modulator provided in one embodiment of the present application;

[0049] Figure 4 1 is a schematic structural diagram of an incident waveguide structure of a spatial light modulator provided in one embodiment of the present application;

[0050] Figure 5 1 is a schematic structural diagram of a spatial light modulator self-test device provided in one embodiment of the present application;

[0051] Figure 61 is a schematic diagram of the self-test working principle of the spatial light modulator self-test device provided by one embodiment of the present application;

[0052] Figure 7 is a schematic structural diagram of an optical computing device provided in one embodiment of the present application;

[0053] Figure 8 is a schematic diagram of the working principle of an optical computing device provided by an embodiment of the present application;

[0054] Figure 9 is an image to be recognized by optical calculation provided by an embodiment of the present application;

[0055] Figure 10 It is a pattern detected by the photodetector of the optical computing device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0056] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clearly understood, the embodiments of the present application are further described in detail below with reference to the accompanying drawings. The illustrative embodiments of the present application and their descriptions are used to explain the present application but are not intended to limit the present application. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application may be combined with each other in any manner.

[0057] Figure 2 is a structural diagram of a spatial light modulator provided in one embodiment of the present application, such as Figure 2 As shown, the spatial light modulator provided by the present application includes: an incident waveguide structure 1, a cover plate 2, a liquid crystal layer 3, a substrate 4 and an output waveguide structure 5;

[0058] The incident waveguide structure 1 is optically coupled to the cover plate 2 to guide externally incident laser light into the cover plate 2 at a preset angle;

[0059] The cover plate 2 is used to allow the laser to propagate in the form of total reflection inside the cover plate 2;

[0060] The substrate 4 carries the liquid crystal layer 3 and integrates a driving circuit for applying a regulating voltage to the liquid crystal layer 3;

[0061] The liquid crystal layer 3 is provided on the lower side of the cover plate 2 and is used to perform phase modulation on the laser light that is totally reflected and propagates to the liquid crystal layer 3 in response to the control voltage;

[0062] The output waveguide structure 5 is optically coupled to the cover plate 2 and is used to guide the laser light modulated by the liquid crystal layer 3 out of the cover plate 2 into free space.

[0063] Specifically, the incident waveguide structure 1 is disposed on the light-incoming side of the superstrate 2 and optically coupled to the superstrate 2. The incident waveguide structure 1 is used to receive laser light from the outside and guide the laser light into the superstrate 2 at a preset angle, thereby achieving an effective transition of the laser light from free space to the waveguide structure.

[0064] Cover plate 2 is a transparent medium with a high refractive index, supporting total internal reflection of the laser beam. By controlling the laser's incident angle, the laser beam meets the conditions for total internal reflection, forming a zigzag guided mode propagation path within cover plate 2. This reduces energy loss during propagation and maintains good beam quality.

[0065] Liquid crystal layer 3 is positioned beneath cover plate 2, near the laser's total internal reflection propagation path. It modulates the laser's phase at each reflection point. Liquid crystal molecules in liquid crystal layer 3 change their orientation in response to an applied voltage, causing a phase shift in the incident laser wavefront, enabling dynamic control of the light field.

[0066] Substrate 4, the supporting structure for liquid crystal layer 3, is located beneath it. It integrates a driver circuit that provides pixel-level control voltages to liquid crystal layer 3, thereby precisely controlling the effect of each modulation unit on the phase of the incident light. This structural design enables point-by-point modulation of the reflected laser light's spatial position, meeting the requirements of complex light field processing.

[0067] The output waveguide structure 5 is positioned on the light-emitting side of the cover plate 2 and optically coupled to the cover plate 2. It effectively conducts the laser light modulated by the liquid crystal layer 3 from the cover plate 2 into free space. This structure ensures that the energy and wavefront shape of the modulated light field are output stably, making it suitable for subsequent optical signal detection or processing.

[0068] By constructing a guided-mode light propagation path in the cover plate 2 and combining the liquid crystal layer 3 with the integrated circuit drive, spatial phase modulation of the laser light field is achieved. It has the advantages of compact structure, high control accuracy, and low optical efficiency loss, and can be widely adapted to various spatial light application systems.

[0069] Figure 3 FIG. 1 is a schematic structural diagram of an incident waveguide structure 1 of a spatial light modulator provided in one embodiment of the present application. Figure 3 As shown, the incident waveguide structure 1 adopts an edge coupling design, and is a microprism array or a gradient refractive index lens integrated at one end of the cover plate 2.

[0070] Specifically, the incident waveguide structure 1 adopts an edge-coupling design, and its structural form is a coupling unit disposed at one end of the cover plate 2. The coupling unit may include a microprism array or a graded refractive index (GRIN) lens, which is used to efficiently guide laser light from free space into the interior of the cover plate 2.

[0071] Edge coupling refers to the laser being incident from space in a direction substantially parallel to the plane of the cover plate 2. By integrating microstructures with optical refraction or reflection functions on the end face of the cover plate 2, the propagation direction of the laser is matched with the propagation path of the guided mode in the cover plate 2, meeting specific incident angle conditions, thereby achieving low-loss coupling.

[0072] Microprism arrays, through precisely designed bevel angles and material refractive indices, can deflect and collimate the laser beam, ensuring it meets the critical angle required for entry into cover plate 2. Compared to single optical components, microprism arrays offer advantages in beam shaping and improved coupling efficiency. GRIN lenses, on the other hand, focus and adjust the direction of incident light by creating a continuously varying refractive index profile within the lens. Their compact structure and high alignment tolerance make them suitable for use in highly integrated spatial light modulation devices.

[0073] The use of edge coupling can effectively reduce space occupancy and improve the system's mechanical stability and environmental adaptability. It is suitable for use in laser communications or optical chip scenarios that have high requirements for compactness and stability.

[0074] In one embodiment, the output waveguide structure 5 adopts an edge-coupled design, and is a microprism array or a gradient refractive index lens integrated at the other end of the cover plate 2 and symmetrical to the input waveguide structure 1 .

[0075] Specifically, the output waveguide structure 5 also adopts an edge coupling design, and its setting position is symmetrical with the input waveguide structure 1 at both ends of the cover plate 2, thereby forming a high-efficiency optical coupling structure of the input and output paths.

[0076] The output waveguide structure 5 can be integrated at the other end of the cover plate 2. Different from the design logic of the incident waveguide structure 1 that constrains the light field through total reflection, the output waveguide structure 5 realizes the release of the light field by precisely breaking the total reflection condition, for example, by using a microprism array or a gradient refractive index lens.

[0077] Among them, the microprism array can be structurally designed according to the output angle of the laser when it is transmitted in the cover plate 2. Through its inclined surface or refractive structure, the modulated laser is guided from the glass waveguide to the free space, thereby realizing the effective release of the light beam; the diffraction grating diffracts and couples the guided mode light field through the periodic microstructure, breaking the total reflection condition and allowing part of the light to be emitted in a specific direction. It has the advantages of compact structure and precise control of the output angle.

[0078] This symmetrical design allows the laser to enter the cover plate 2 via a total reflection path from one end and exit at a similar angle from the other end, maximizing the consistency and stability of the optical path. Furthermore, edge coupling offers higher output coupling efficiency than free-space reflection, making it particularly suitable for applications requiring high light field directionality and energy efficiency.

[0079] Through this structure, the output waveguide structure 5 can stably release the light beam modulated by the liquid crystal layer 3 from the cover plate 2, providing high-quality optical signal output for subsequent photoelectric detection, interferometry or optical computing processing.

[0080] In one embodiment, when the guided mode light field is transmitted to the outcoupling region at an angle θ, the output waveguide structure 5 (such as the inclined surface of a microprism or the periodic structure of a grating) changes the incident angle of the light field, making the incident angle of part of the light field smaller than the critical angle (sinφ<1 / n), thereby breaking through the total internal reflection limitation and refracting into free space at a specific angle (usually symmetrical with the incident angle).

[0081] Figure 4 FIG. 1 is a schematic structural diagram of an incident waveguide structure 1 of a spatial light modulator provided in one embodiment of the present application. Figure 4 As shown, the incident waveguide structure 1 adopts a front coupling design, and is an embossed grating, a volume grating or a microprism integrated on the upper surface or the lower surface of the cover plate 2.

[0082] Specifically, the incident waveguide structure 1 adopts a front coupling design, and its structural feature is that a coupling microstructure is integrated on the upper surface or lower surface of the cover plate 2 to effectively guide the external laser into the cover plate 2 after being incident in a vertical or near-vertical direction.

[0083] Front coupling differs from edge coupling in that its main advantage is that the laser light source can be directly illuminated vertically from space onto the device surface, simplifying optical alignment and enabling compact system packaging. To achieve this coupling method, a relief grating, volume grating, or microprism structure can be placed on the surface of cover plate 2.

[0084] Among them, the relief grating is a periodic microstructure etched on the surface of the cover plate 2, which can diffract the vertically incident laser at a certain angle so that it meets the total reflection propagation conditions inside the glass. The relief grating has the advantages of mature processing technology, strong wavelength selectivity, and easy large-scale manufacturing. The volume grating is a volume diffraction structure formed by changing the refractive index distribution inside the material, which can achieve high-efficiency beam coupling under specific incident angle and wavelength conditions. Compared with the surface grating, the volume grating has higher diffraction efficiency and angle selectivity, and is suitable for directional coupling scenarios; among them, the microprism can be structurally designed according to the incident angle of the laser when it is transmitted in the cover plate 2, and the modulated laser is guided from free space to the glass waveguide through its inclined surface or refractive structure to achieve effective coupling of the light beam.

[0085] Through the front coupling structure design, the incident waveguide structure 1 can efficiently introduce external laser into the interior of the cover plate 2 without occupying the side space of the cover plate 2, thereby improving the applicability of the device in highly integrated, small-size systems and providing a flexible coupling solution for multi-modal incidence methods.

[0086] In one embodiment, the output waveguide structure 5 adopts a front coupling design, and is a relief grating, a volume grating or a microprism integrated on the upper surface or the lower surface of the cover plate 2 .

[0087] Specifically, the output waveguide structure 5 adopts a front coupling design, and its structural form is an integrated coupling microstructure on the upper surface or lower surface of the cover plate 2, which is used to guide the laser propagating in the cover plate 2 out to the free space.

[0088] The front coupling structure is symmetrical with the incident side structure, which facilitates the unified design of the optical path. In order to achieve stable emission of light from the inside of the cover plate 2, the front coupling structure can be a relief grating, a volume grating or a micro prism or a micro prism.

[0089] A relief grating is a periodic refractive interface structure constructed on the surface of cover plate 2. Its function is to adjust the propagation direction of the light field, breaking the condition of total internal reflection, thereby causing a portion of the guided mode light to exit cover plate 2 at a predetermined angle and emit into free space. This structure features simple fabrication and flexible response wavelength, making it suitable for emission control across most operating bands. A volume grating, on the other hand, creates an optical structure with a periodically varying refractive index within the interior of cover plate 2, causing Bragg diffraction of the laser light upon propagation into this region, resulting in its emission from cover plate 2 with a specific direction and efficiency. This structure allows for precise control of the emission angle, making it suitable for applications requiring high light directionality.

[0090] The use of front coupling can reduce dependence on the side structure of the cover plate 2, and is suitable for use in systems with limited space or that require vertical light output. It also helps to integrate and match with planar structures such as photodetectors and optical chips, thereby improving the consistency and scalability of system packaging.

[0091] In one embodiment, the liquid crystal layer 3 is fixed between the cover plate 2 and the substrate 4 by optical adhesive.

[0092] Specifically, the liquid crystal layer 3 is fixed between the cover plate 2 and the substrate 4 using optical adhesive, thereby constructing a stable multi-layer modulation structure. The optical adhesive is used to form an optically transparent and mechanically stable bonding layer between the liquid crystal layer 3, the cover plate 2, and the substrate 4. Compared with traditional physical compression structures, optical adhesive fixing has the following advantages:

[0093] First, optical adhesive offers excellent light transmittance and a low refractive index, effectively preventing interfacial reflection and interference, ensuring wavefront continuity and intensity uniformity before and after laser modulation in the liquid crystal layer 3, thereby improving the overall optical performance of the system. Second, optical adhesive bonding significantly enhances the stability of the liquid crystal layer 3 in complex operating environments, particularly in thermal cycling, mechanical vibration, and aerospace environments, effectively preventing warping, displacement, or delamination of the liquid crystal layer 3.

[0094] In addition, the use of optical adhesive also facilitates the control of interlayer thickness in the manufacturing process, and can accurately define the thickness of the liquid crystal layer 3, thereby ensuring the response uniformity of the liquid crystal molecules under the action of the electric field and the consistency of the phase modulation, thereby improving the repeatability and reliability of the modulation device.

[0095] Through the above-mentioned method, the physical position and optical state of the liquid crystal layer 3 in the spatial light modulator are ensured to remain stable, providing a solid structural foundation for achieving high-precision and high-consistency spatial phase modulation.

[0096] In one embodiment, the substrate 4 is a silicon-based substrate, and the driving circuit is a semiconductor transistor array.

[0097] Specifically, the substrate 4 is a silicon-based substrate, and a semiconductor transistor (CMOS) array is integrated on the substrate 4 for driving and controlling the modulation state of the liquid crystal layer 3 .

[0098] Silicon substrates, with their excellent mechanical strength, thermal stability, and compatibility with micro- and nanofabrication, are ideal as the substrate material for the electronic drivers in spatial light modulators. Their excellent thermal conductivity helps maintain a stable temperature distribution during long-term continuous operation, preventing drift in the liquid crystal response characteristics due to localized overheating.

[0099] A semiconductor transistor array is distributed on a silicon substrate, forming a voltage-driven network for each pixel in the liquid crystal layer 3. Each semiconductor transistor unit can independently control the electric field intensity at its corresponding pixel, thereby achieving local modulation of the liquid crystal molecular alignment and ultimately controlling the phase of the laser wavefront on a pixel-by-pixel basis.

[0100] Using a CMOS array as a driving circuit has the following advantages: it supports high-resolution pixel matrix driving and is suitable for high-precision phase modulation requirements; it can achieve fast response and grayscale control and adapt to multi-level phase changes; it has low power consumption and highly integrated circuit characteristics, which facilitates device miniaturization and system-level packaging.

[0101] By integrating a silicon substrate with a CMOS driver circuit, the spatial light modulator not only has the capability of precise electrically controlled phase modulation, but also can meet the requirements of dynamic loading and fast switching of complex modulation patterns, thereby enhancing its practical value in high-performance optical systems.

[0102] In one embodiment, the CMOS driving circuit on the silicon substrate 4 can apply a 0-5V voltage to the liquid crystal layer 3, and realize 0-2π continuous phase modulation by changing the orientation of the liquid crystal molecules. The modulation relationship satisfies: Δφ = (2π / λ)·Δn·d, where Δn is the tuning amount of the liquid crystal refractive index, d is the thickness of the liquid crystal layer 3, and λ is the operating wavelength.

[0103] In one embodiment, the cover plate 2 is made of glass material, and the light beam reflection points in the cover plate 2 are located at a plurality of preset positions corresponding to a plurality of independent working areas divided on the liquid crystal layer 3 .

[0104] Specifically, the cover plate 2 is made of glass material, which has good optical transparency and mechanical stability, and is suitable for constructing a waveguide structure in which laser light propagates in a guided mode.

[0105] Glass, with its high refractive index, low absorption rate, and excellent surface finish, supports stable laser propagation through total internal reflection, while ensuring no significant degradation in beam quality during multiple reflections. Furthermore, its stable thermal expansion coefficient makes it suitable for optical systems operating for extended periods in complex environments.

[0106] The glass cover plate 2 serves as the optical waveguide substrate, responsible for the total internal reflection transmission of the laser light. Within the glass cover plate 2, the laser light propagates along a designed total internal reflection path, forming multiple reflection points. To achieve orderly and controllable light field modulation, the beam reflection points are designed to be located at multiple preset positions, spatially corresponding to different regions within the liquid crystal layer 3.

[0107] This structural design allows each laser reflection point to precisely correspond to a working area in the liquid crystal layer 3, thus enabling multiple modulations based on a reflection sequence. Unlike the single-shot modulation of existing technologies, each area can be independently loaded with a phase hologram, modulating the light field region by region. As the laser passes through each reflection point, it interacts with a localized area of ​​the liquid crystal layer 3, achieving phase modulation in a staged, sequential manner. This arrangement not only enhances the hierarchical nature of the modulation but also provides a high degree of structural controllability in the light field processing process.

[0108] By using glass material as the guiding medium and designing multiple preset reflection point positions inside it, a one-to-one correspondence is formed with the liquid crystal modulation structure, providing an optical basis for building a high-precision, multi-level phase modulation system, and improving the capability and flexibility of the spatial light modulator in complex modulation tasks.

[0109] In one embodiment, the plurality of independent working areas divided on the liquid crystal layer 3 include 100×100 pixel partitions.

[0110] In one embodiment, pixel intervals are set between the multiple independent working areas.

[0111] Specifically, the liquid crystal layer 3 is divided into a plurality of independent working areas according to the positions of a plurality of reflection points of the light beam in the cover plate 2 , so as to achieve local modulation of the light field at different positions.

[0112] To avoid optical interference between adjacent working areas, pixel gaps are set between multiple independent working areas. These gaps refer to the rows or columns of non-modulated pixels located between adjacent areas. These pixels do not participate in the modulation signal loading in the circuit drive and do not perform phase modulation optically.

[0113] The pixel spacing setting has the following technical functions: 1. Reducing optical crosstalk. During laser beam propagation, side lobes and reflection divergence occur. By setting spacing between adjacent regions, lateral coupling between modulated wavefronts can be effectively suppressed, improving the independence of modulation results in each region; 2. Buffering phase transition regions. When the phase patterns loaded in different working regions change dramatically, the spacing region acts as a transition buffer, helping to control phase distortion or discontinuity at the modulation boundary; 3. Improving modulation accuracy and stability. The pixel spacing provides structural redundancy, reducing the mismodulation of adjacent regions caused by non-ideal liquid crystal response or driving errors, and improving the stability of the overall system in multi-level modulation scenarios.

[0114] By introducing pixel spacing between multiple independent working areas, spatial light field modulation with higher resolution and lower interference can be achieved, providing a reliable structural foundation for multi-step control, regional processing, and even parallel optical computing.

[0115] In one embodiment, a spacing of 5-10 pixels is set between the multiple independent working areas to avoid optical crosstalk.

[0116] In one embodiment, the preset angle is calculated based on the refractive index of the cover plate 2 and is greater than or equal to the critical angle of the cover plate 2 .

[0117] Specifically, the incident waveguide structure 1 is used to guide external laser light into the interior of the cover plate 2 at a preset angle so that the laser light satisfies the total internal reflection propagation condition therein. The preset angle is set based on the optical properties of the cover plate 2 material, especially its refractive index.

[0118] The preset angle is calculated based on the refractive index of the cover plate 2 and satisfies the condition of being greater than or equal to the critical angle of the cover plate 2, so as to ensure that the laser does not leak at the interface between the cover plate 2 and the external air, but always propagates inside the cover plate 2 in the form of total reflection.

[0119] By precisely designing the incident angle, the laser can propagate along a zigzag or stepped reflection path in the cover plate 2, thereby minimizing energy loss and improving light transmission efficiency and stability.

[0120] This design not only ensures the low-loss guided mode transmission characteristics of the laser inside the cover plate 2, but also provides a stable light field foundation for the subsequent phase modulation interaction with the liquid crystal layer 3, which is conducive to achieving precise and high-fidelity optical modulation functions.

[0121] In one embodiment, the critical angle is a critical value derived from Snell's law. For a cover plate 2 material with a refractive index of n, the critical angle θ is p Satisfy: θ p =arcsin(n0 / n), where n0 is the refractive index of the external medium (usually air, n0≈1), and n is the refractive index of the glass cover 2.

[0122] In order to ensure that the laser forms a stable guided mode path in the cover plate 2, the preset angle θ in Should satisfy: θ in ≥θ p .

[0123] When the laser is incident from air (refractive index n0≈1) to the glass cover 2 (refractive index n, n>1), the incident angle θ is precisely controlled. in >=arcsin(1 / n), so that the light meets the total reflection condition on the upper and lower surfaces of the cover plate 2. At this time, the laser is reflected in the cover plate 2 with Angle of incidence interface, due to A low-loss zigzag transmission path is formed, effectively avoiding the energy attenuation and optical path deviation problems in free-space transmission.

[0124] In one embodiment, the laser light with wavelength λ is in The angle is >= arcsin(1 / n) and coupled to the glass cover plate 2. Its optically dense medium properties are used to achieve low-loss guided mode transmission (loss <0.5dB / cm). The silicon substrate 4 only serves as a modulation layer carrier and does not participate in light transmission. The guided mode light field perpendicularly incident on the liquid crystal layer 3 of the silicon substrate 4 is modulated by the phase hologram independently loaded in each working area: for example, the first working area is loaded with a Fu blazed grating hologram to achieve laser steering / spectrum shifting; the second working area is loaded with a convolution kernel hologram to perform optical convolution operations; and the third working area is loaded with a Fresnel lens hologram to perform frequency domain transformation. The modulation process satisfies the cascade transformation relationship: E out =M k ·T·…·M2·T·M1·T·E in , where M i is the real-time phase modulation matrix for the corresponding region, and T is the transmission matrix. The modulated light field is recoupled to the glass cover plate 2 through total internal reflection, output through the symmetrically structured output waveguide at the same angle as the input, and transmitted by the collimating lens to the detection end or subsequent processing unit.

[0125] The present application provides a spatial light modulator, which includes: an incident waveguide structure, a cover plate, a liquid crystal layer, a substrate, and an output waveguide structure; the incident waveguide structure is optically coupled to the cover plate and is used to guide externally incident laser light into the cover plate at a preset angle; the cover plate is used to cause the laser light to propagate within it in the form of total internal reflection; the substrate carries the liquid crystal layer and has an integrated drive circuit for applying a control voltage to the liquid crystal layer; the liquid crystal layer is disposed on the underside of the cover plate and is used to phase-modulate the laser light that is totally reflected and propagates into the liquid crystal layer in response to the control voltage; the output waveguide structure is optically coupled to the cover plate and is used to guide the laser light modulated by the liquid crystal layer from the cover plate to free space. The spatial light modulator provided by the present application achieves efficient spatial modulation and precise control of the light field, thereby improving the integration and functional accuracy of the spatial light modulator in self-test and optical computing.

[0126] Among them, through the optical coupling of the incident waveguide structure and the cover plate, the laser is efficiently and stably coupled from free space into the cover plate, effectively avoiding the problems of energy diffusion, high difficulty in collimation and poor anti-interference ability in traditional free space propagation, and improving the compactness of the system and the accuracy of light field control; through the preset angle coupling and satisfying total reflection propagation, it is guaranteed that the laser propagates stably in the form of total reflection in the cover plate, constructing a low-loss, high-fidelity optical transmission path, and providing basic support for multi-level modulation of the light field after multiple reflections; by utilizing the geometric layout of the liquid crystal layer close to the total reflection path, local interferometric phase modulation of the incident light is achieved without interfering with the main transmission The overall structure of the path ensures the spatial resolution and accuracy of the modulation. Through the integrated drive circuit on the substrate, the liquid crystal pixels are finely controlled, which can support independent voltage control of each pixel in the liquid crystal layer, forming a programmable, real-time responsive two-dimensional phase modulation array, so that the spatial light modulator has a high degree of freedom of light field modulation capability, which can adapt to different optical signal processing requirements. Through the coupling of the output waveguide structure with the cover plate, the modulated light is derived, and the incident light after phase modulation is stably emitted from the cover plate into free space, effectively maintaining the light field wavefront structure and energy distribution, and providing controllable, high-quality light output for subsequent optical computing, communication or detection links.

[0127] Figure 5 FIG. 1 is a structural diagram of a spatial light modulator self-test device provided in an embodiment of the present application. Figure 5 As shown, the spatial light modulator self-test device provided by the present application includes: a laser light source 6, a photodetector 7 and the spatial light modulator described in any of the above embodiments;

[0128] The laser light source 6 is arranged on the light-incoming side of the incident waveguide structure 1 and is used to emit detection laser;

[0129] The incident waveguide structure 1 is used to receive the detection laser and guide the detection laser into the cover plate 2 at a preset angle;

[0130] The cover plate 2 is used to allow the detection laser to propagate in the form of total reflection inside the cover plate 2;

[0131] The substrate 4 is used to apply a control voltage to the liquid crystal layer 3;

[0132] The liquid crystal layer 3 is used to perform phase modulation on the detection laser light that is totally reflected and propagates to the liquid crystal layer 3 in response to the control voltage;

[0133] The output waveguide structure 5 is used to guide the detection laser modulated by the liquid crystal layer 3 out of the cover plate 2 into free space and guide it to the photodetector 7;

[0134] The photodetector 7 is disposed on the light-emitting side of the output waveguide structure 5 and is used to detect the power of the modulated detection laser to determine the working state of the spatial light modulator.

[0135] Specifically, the detection laser is emitted by the laser light source 6 and enters the incident waveguide structure 1 on its light output side. The detection laser has good directionality and stability and can pass through subsequent optical modules as a detection signal. The self-test function can operate independently.

[0136] The incident waveguide structure 1 is used to guide the detection laser light emitted by the laser light source 6, ensuring that it has a clear propagation direction and incident angle before entering the cover plate 2. By properly designing the incident path, the detection laser light can form a stable optical propagation state in the modulator, facilitating subsequent modulation and energy analysis.

[0137] Cover plate 2 is a transparent medium with a high refractive index, supporting the detection laser's propagation through total internal reflection. By controlling the detection laser's incident angle, the detection laser meets the conditions for total internal reflection, forming a zigzag propagation path within cover plate 2. This reduces energy loss during propagation and maintains good beam quality.

[0138] Liquid crystal layer 3 is positioned beneath cover plate 2, near the laser's total internal reflection propagation path. It modulates the phase of the detection laser at each reflection point. Liquid crystal molecules in liquid crystal layer 3 change their orientation in response to an applied voltage, causing a phase shift in the detection laser's wavefront, enabling dynamic control of the light field.

[0139] Substrate 4, the supporting structure for liquid crystal layer 3, is located beneath it. It integrates a driver circuit that provides pixel-level control voltages to liquid crystal layer 3, thereby precisely controlling the effect of each modulation unit on the phase of the detection laser. This structural design enables point-by-point modulation of the detection laser's spatial position, meeting the requirements of complex light field processing.

[0140] The output waveguide structure 5 is positioned on the light-emitting side of the cover plate 2 and optically coupled to the cover plate 2. It effectively directs the detection laser light modulated by the liquid crystal layer 3 from the cover plate 2 into free space. This structure ensures that the energy and wavefront shape of the modulated light field are output stably, making it suitable for subsequent optical signal detection or processing.

[0141] The photodetector 7 measures the laser power and converts the optical signal into an electrical signal for output. Based on the obtained electrical signal intensity change, it can be determined whether the spatial light modulator is in normal working state, thereby achieving effective monitoring of the spatial light modulator function state.

[0142] Through the coordinated work of the above structures, accurate and contactless self-inspection of the spatial light modulator can be achieved without affecting the operation of the main system. It has the advantages of simple structure and fast response, and is suitable for spaceborne environments.

[0143] Figure 6 FIG. 1 is a schematic diagram of the self-test working principle of the spatial light modulator self-test device provided in one embodiment of the present application. Figure 6 As shown, the light beam reflection points in the cover plate 2 are located at multiple preset positions, corresponding to the multiple independent working areas divided on the liquid crystal layer 3. Blazed grating patterns are displayed in sequence in the multiple independent working areas, and the reflection angle of the detection laser is changed to perform functional detection on the multiple independent working areas.

[0144] Specifically, the spatial light modulator is divided into a plurality of independent working areas (detection areas), each of which displays a different modulation pattern, so as to detect the modulation function of each detection area one by one.

[0145] In practice, phase patterns (blazed grating patterns) with specific optical functions are sequentially applied to multiple detection zones. These patterns introduce a phase gradient to the incident detection laser, thereby altering its reflection direction. This shift in reflection angle effectively disrupts the original total internal reflection propagation path, causing some detection light to leak or deflect, thereby changing the output characteristics of the beam.

[0146] The output optical power measurements from photodetector 7 can be used to determine whether the currently activated detection zone has normal modulation capabilities. When the detection zone is functioning properly, loading the blazed grating will result in a significant change in the output light energy. If the zone is inoperative or exhibits an abnormal response, the reflection characteristics will not change as expected, and the output optical power will remain essentially unchanged. Thus, by sequentially switching detection zones and analyzing the response of each zone, the spatial light modulator's functional characteristics can be tested in separate zones.

[0147] The above structure enables self-inspection in each area without external intervention, facilitating regular assessment of device health status and effectively improving system stability and fault location efficiency.

[0148] In one embodiment, if Figure 6 As shown, in the normal state (the spatial light modulator is closed), the spatial light modulator is equivalent to a strip waveguide, and the detection laser undergoes multiple consecutive total reflections, such as Figure 6 As shown by the white light in the middle, all the energy finally enters the photodetector 7 under the condition of ignoring other non-optical losses.

[0149] In the detection state (spatial light modulator is on), the liquid crystal layer 3 is divided into different working areas according to the position of the light beam reflection point. Function detection is performed area by area starting from the incident end of the detection light. By displaying a blazed grating in the area, the incident light is deflected in the normal direction (i.e. Figure 6 (As shown by the black light in the middle, white light propagates within the cover plate 2 at a total reflection angle, while the black light's reflection angle is smaller than this, causing some light to be transmitted. Ultimately, after multiple incomplete reflections, the energy decays to zero. Testing by the output photodetector 7 reveals whether each region of the spatial light modulator is functioning properly. The same method can be used to perform region-by-region functional testing of the spatial light modulator. To ensure accurate testing near the output end, the distance from the output waveguide structure 5 to the liquid crystal layer 3 is appropriately extended. This allows the test laser to be further reflected within the output waveguide structure 5, amplifying the energy difference detected by the photodetector 7 when the spatial light modulator is operating and not operating.

[0150] In one embodiment, the length of the output waveguide structure 5 from the liquid crystal layer 3 is greater than the length of the input waveguide structure 1 from the liquid crystal layer 3, so as to enhance the energy difference of the modulated detection laser when the spatial light modulator is in working or non-working state.

[0151] Specifically, as the detection laser propagates through the spatial light modulator, the propagation direction and power of the outgoing light vary depending on the spatial light modulator's current operating state. After the modulated laser enters the output waveguide structure 5, its energy distribution and directional characteristics directly affect the optical power ultimately reaching the photodetector 7. By appropriately extending the length of the output waveguide structure 5 relative to the liquid crystal layer 3, the propagation distance and number of reflections of the modulated detection laser light can be increased, further widening the difference in light intensity output between different modulation states and thus acting as a signal amplifier.

[0152] When the spatial light modulator (SLM) doesn't deflect the detection laser light, the beam maintains high efficiency propagation within the waveguide structure. However, once deflection occurs, the beam experiences significant attenuation or offset during long-distance propagation, causing significant changes in the signal power received by photodetector 7. Therefore, the relatively long output waveguide structure 5 helps enhance the optical power difference before and after SLM modulation, improving photodetector 7's sensitivity to state changes and ultimately enhancing the overall detection accuracy and robustness of the self-test device.

[0153] In one embodiment, the laser light source 6 is a red semiconductor laser with a wavelength of 635 nm.

[0154] In one embodiment, the photodetector 7 is a silicon-based balanced photodetector.

[0155] Specifically, the photodetector 7 is a silicon-based balanced photodetector, which is used to receive the modulated detection laser and convert its light intensity into an electrical signal output for subsequent judgment of the working state of the spatial light modulator.

[0156] Silicon-based balanced photodetectors offer high photoelectric conversion efficiency and high sensitivity, enabling precise responses to minute optical power variations. They are particularly well-suited for low-power laser detection within a narrow wavelength range. Their balanced detection structure effectively suppresses background noise and common-mode interference, improving measurement accuracy. They can also output a stable electrical signal even with small variations in detected optical power, facilitating the identification of subtle optical response differences within the operating state of a spatial light modulator.

[0157] When the spatial light modulator is in different states, the output optical power will change accordingly, and the photodetector 7 can convert this power change into an electrical signal. Based on the amplitude change or trend characteristics of the electrical signal, it can be determined whether the current operating state of the modulator is normal.

[0158] The present application provides a spatial light modulator and its self-test device, the spatial light modulator comprising: an incident waveguide structure, a cover plate, a liquid crystal layer, a substrate, and an output waveguide structure; the incident waveguide structure is optically coupled to the cover plate, and is used to guide externally incident laser light into the cover plate at a preset angle; the cover plate is used to cause the laser light to propagate in the form of total reflection within the cover plate; the substrate carries the liquid crystal layer and has an integrated drive circuit for applying a control voltage to the liquid crystal layer; the liquid crystal layer is disposed on the underside of the cover plate, and is used to phase-modulate the laser light that is totally reflected and propagates into the liquid crystal layer in response to the control voltage; the output waveguide structure is optically coupled to the cover plate, and is used to guide the laser light modulated by the liquid crystal layer from the cover plate to free space. The spatial light modulator and its self-test device provided by the present application achieve efficient spatial modulation and precise control of the light field, thereby improving the integration and functional accuracy of the spatial light modulator in self-test and optical computing.

[0159] Among them, through the optical coupling of the incident waveguide structure and the cover plate, the laser is efficiently and stably coupled from free space into the cover plate, effectively avoiding the problems of energy diffusion, high difficulty in collimation and poor anti-interference ability in traditional free space propagation, and improving the compactness of the system and the accuracy of light field control; through the preset angle coupling and satisfying total reflection propagation, it is guaranteed that the laser propagates stably in the form of total reflection in the cover plate, constructing a low-loss, high-fidelity optical transmission path, and providing basic support for multi-level modulation of the light field after multiple reflections; by utilizing the geometric layout of the liquid crystal layer close to the total reflection path, local interferometric phase modulation of the incident light is achieved without interfering with the main transmission The overall structure of the path ensures the spatial resolution and accuracy of the modulation. Through the integrated drive circuit on the substrate, the liquid crystal pixels are finely controlled, which can support independent voltage control of each pixel in the liquid crystal layer, forming a programmable, real-time responsive two-dimensional phase modulation array, so that the spatial light modulator has a high degree of freedom of light field modulation capability, which can adapt to different optical signal processing requirements. Through the coupling of the output waveguide structure with the cover plate, the modulated light is derived, and the incident light after phase modulation is stably emitted from the cover plate into free space, effectively maintaining the light field wavefront structure and energy distribution, and providing controllable, high-quality light output for subsequent optical computing, communication or detection links.

[0160] The spatial light modulator self-test device provided in this application, by designing a grating waveguide and utilizing the principle of total reflection, realizes compact, sensitive and flexible partition detection of the functional status of each area of ​​the spatial light modulator self-test device without interfering with the normal operation of the communication system, thereby improving the reliability of the system and the maintainability of on-orbit operation. Among them, by adopting an independent detection light source set at the starting point of the self-detection optical path, the physical path separation of the detection laser and the communication signal light is achieved, mutual interference is avoided, and the independence of detection and system compatibility are improved; by setting an incident waveguide to make the detection laser enter the cover plate of the spatial light modulator at a critical angle, the detection laser is realized to undergo multiple total reflections in the cover plate of the spatial light modulator, creating a stable propagation path for subsequent phase modulation and improving the detection sensitivity; by modulating the phase of the detection laser to cause light beam deflection, the total reflection condition is broken, and selective detection of the functional status of different areas is achieved; by extending the detection light path and enhancing the energy difference, the distinguishability of the optical power in different states of the spatial light modulator is improved, thereby improving the detection accuracy; by converting the light energy change into an electrical signal for state judgment, a high-sensitivity electrical signal output judgment of the modulation state of the spatial light modulator is achieved, so that the device has the ability of on-orbit autonomous diagnosis.

[0161] Figure 7 is a schematic diagram of the structure of an optical computing device provided by an embodiment of the present application, such as Figure 7 As shown, the optical computing device provided by the present application includes: a laser light source 8, a digital micromirror 9, a photodetector 10 and the spatial light modulator described in any of the above embodiments;

[0162] The digital micromirror 9 is disposed between the laser light source 8 and the incident waveguide structure 1, and is used to spatially modulate the incident light emitted by the laser light source 8 to form a light field including information to be calculated, and reflect the light field to the incident waveguide structure 1;

[0163] The incident waveguide structure 1 is used to receive the incident light modulated by the digital micromirror 9 and guide the incident light into the cover plate 2 at a preset angle;

[0164] The cover plate 2 is used to allow the incident light to propagate in the form of total reflection inside the cover plate 2, and the multiple reflection points of the reflection path correspond to the multiple independent working areas divided on the liquid crystal layer 3;

[0165] The substrate 4 is used to apply independent control voltages to each working area of ​​the liquid crystal layer 3;

[0166] The liquid crystal layer 3 is used to perform phase modulation on the incident light region by region when the incident light propagates to each reflection point;

[0167] The output waveguide structure 5 is used to guide the incident light after multi-level phase modulation from the cover plate 2 to the free space;

[0168] The photodetector 10 is disposed on the light-emitting side of the output waveguide structure 5 , and is configured to output a detection signal representing a light calculation result based on the output light derived from the output waveguide structure 5 .

[0169] Specifically, the optical computing device constructs a light field computing path based on laser modulation, guided mode propagation and multi-level phase processing, which can be used to perform diffraction neural network tasks such as image recognition and matrix transformation.

[0170] The laser light source 8 is used to generate a laser beam with certain spatial coherence and light intensity stability, which serves as the input carrier of the optical computing process. The laser beam first irradiates the digital micromirror 9.

[0171] A digital micromirror (DMD) 9, positioned between the laser light source 8 and the input waveguide structure 1 of the spatial light modulator, spatially modulates the input laser light according to a predetermined pattern. This modulation process can be used to load information to be calculated. The modulated light field is then reflected by the DMD 9 back into the input waveguide structure 1.

[0172] The incident waveguide structure 1 is used to receive the light field modulated by the DMD and guide it into the cover plate 2 at a preset angle that satisfies the total reflection condition, thereby achieving efficient coupling of the laser from the free space to the guided mode channel.

[0173] The cover plate 2 acts as an optical waveguide medium, causing the incident light to form a zigzag multiple total reflection path inside it. The multiple reflection points on the reflection path spatially correspond to the multiple independent working areas in the liquid crystal layer 3.

[0174] Liquid crystal layer 3 phase modulates the laser light region by region at the reflection points. Each region can be loaded with a different phase mask pattern, which is used to perform specific computational operations on the input light field, such as phase shift, convolution, and Fourier transform. As the light beam propagates through cover plate 2, the liquid crystal region corresponding to each reflection point superimposes a new phase matrix on its light field, resulting in a multi-level modulation effect on the final output light field, equivalent to implementing a multi-layer neural network inference process in optics.

[0175] The substrate 4 carries the liquid crystal layer 3 and integrates the driving circuit, which can apply independent control voltage to each independent working area, thereby achieving flexible control of the phase pattern of different areas, meeting the requirements of multi-layer, reconfigurable and real-time modulation in optical computing.

[0176] The output waveguide structure 5 is used to output the light field after multi-level phase modulation from the cover plate 2 to the free space, ensuring that the light field characteristics of the final calculation result maintain good output quality.

[0177] The photodetector 10 is disposed on the light-emitting side of the output waveguide structure 5 to receive the output light. By detecting the intensity distribution or interference pattern of the output light, an electrical signal representing the optical calculation result can be output for subsequent circuit processing or decision-making system use.

[0178] In one embodiment, the photodetector 10 is a CCD camera.

[0179] In one embodiment, the optical computing works as follows Figure 8 As shown, the information to be calculated is as follows Figure 9 The image to be identified is modulated from the incident end of the detection light to each region. The following is the state of the laser at the first reflection of the liquid crystal layer 3 (i.e. Figure 8 The following is an example of a diffraction layer 1 in the middle. By displaying a phase mask in region 1, the incident light field carrying the information to be calculated is added with a new phase matrix, and after diffraction propagation, a new field distribution is formed and then enters the diffraction layer 2. This process is repeated, and finally, after multiple modulations, the light field is output through the detection of the output photodetector 10 in the output section, and the multi-layer diffraction neural network optical calculation can be realized. The pattern detected by the photodetector 10 is as follows Figure 10 shown.

[0180] The present application provides a spatial light modulator, its self-test device, and optical computing device. The spatial light modulator includes: an incident waveguide structure, a cover plate, a liquid crystal layer, a substrate, and an output waveguide structure. The incident waveguide structure is optically coupled to the cover plate and is used to guide externally incident laser light into the cover plate at a preset angle. The cover plate is used to cause the laser light to propagate within it in the form of total internal reflection. The substrate carries the liquid crystal layer and has an integrated drive circuit for applying a control voltage to the liquid crystal layer. The liquid crystal layer is disposed on the underside of the cover plate and is used to phase-modulate the laser light that has been totally reflected and propagated into the liquid crystal layer in response to the control voltage. The output waveguide structure is optically coupled to the cover plate and is used to guide the laser light modulated by the liquid crystal layer from the cover plate to free space. The spatial light modulator, its self-test device, and optical computing device provided in the present application achieve efficient spatial modulation and precise control of the light field, thereby improving the integration and functional accuracy of the spatial light modulator in self-test and optical computing.

[0181] Among them, through the optical coupling of the incident waveguide structure and the cover plate, the laser is efficiently and stably coupled from free space into the cover plate, effectively avoiding the problems of energy diffusion, high difficulty in collimation and poor anti-interference ability in traditional free space propagation, and improving the compactness of the system and the accuracy of light field control; through the preset angle coupling and satisfying total reflection propagation, it is guaranteed that the laser propagates stably in the form of total reflection in the cover plate, constructing a low-loss, high-fidelity optical transmission path, and providing basic support for multi-level modulation of the light field after multiple reflections; by utilizing the geometric layout of the liquid crystal layer close to the total reflection path, local interferometric phase modulation of the incident light is achieved without interfering with the main transmission The overall structure of the path ensures the spatial resolution and accuracy of the modulation. Through the integrated drive circuit on the substrate, the liquid crystal pixels are finely controlled, which can support independent voltage control of each pixel in the liquid crystal layer, forming a programmable, real-time responsive two-dimensional phase modulation array, so that the spatial light modulator has a high degree of freedom of light field modulation capability, which can adapt to different optical signal processing requirements. Through the coupling of the output waveguide structure with the cover plate, the modulated light is derived, and the incident light after phase modulation is stably emitted from the cover plate into free space, effectively maintaining the light field wavefront structure and energy distribution, and providing controllable, high-quality light output for subsequent optical computing, communication or detection links.

[0182] The spatial light modulator self-test device provided in this application, by designing a volume grating waveguide and utilizing the principle of total reflection, realizes compact, sensitive and flexible partition detection of the functional status of each area of ​​the spatial light modulator self-test device without interfering with the normal operation of the communication system, thereby improving the reliability of the system and the maintainability of on-orbit operation. Among them, by adopting an independent detection light source set at the starting point of the self-detection optical path, the physical path separation of the detection laser and the communication signal light is achieved, mutual interference is avoided, and the independence of detection and system compatibility are improved; by setting an incident waveguide to make the detection laser enter the cover plate of the spatial light modulator at a critical angle, the detection laser is realized to undergo multiple total reflections in the cover plate of the spatial light modulator, creating a stable propagation path for subsequent phase modulation and improving the detection sensitivity; by modulating the phase of the detection laser to cause light beam deflection, the total reflection condition is broken, and selective detection of the functional status of different areas is achieved; by extending the detection light path and enhancing the energy difference, the distinguishability of the optical power in different states of the spatial light modulator is improved, thereby improving the detection accuracy; by converting the light energy change into an electrical signal for state judgment, a high-sensitivity electrical signal output judgment of the modulation state of the spatial light modulator is achieved, so that the device has the ability of on-orbit autonomous diagnosis.

[0183] The optical computing device provided in this application integrates input modulation, waveguide transmission, layer-by-layer modulation and final detection links into one, thereby constructing an optical computing platform with a compact structure, fast response and no need for intermediate electronic conversion. It is suitable for realizing new artificial intelligence hardware tasks such as optical neural networks, image processing and computing acceleration.

[0184] In the description of this specification, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "multiple" means two or more.

[0185] The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps therein is not limited and can be appropriately adjusted as needed.

[0186] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0187] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A spatial light modulator, characterized in that: include: Incident waveguide structure, cover plate, liquid crystal layer, substrate and output waveguide structure; The incident waveguide structure is optically coupled to the cover plate, and is used to guide externally incident laser light into the cover plate at a preset angle; The cover plate is used to allow the laser to propagate in the form of total reflection inside the cover plate; The substrate carries the liquid crystal layer and integrates a driving circuit for applying a regulating voltage to the liquid crystal layer; The liquid crystal layer is provided on the lower side of the cover plate, and is used for performing phase modulation on the laser light that is totally reflected and propagates to the liquid crystal layer in response to the control voltage; The output waveguide structure is optically coupled to the cover plate and is used to guide the laser light modulated by the liquid crystal layer out of the cover plate and into free space.

2. The spatial light modulator according to claim 1, wherein The incident waveguide structure adopts an edge coupling design and is a microprism array or a gradient refractive index lens integrated at one end of the cover plate.

3. The spatial light modulator according to claim 2, wherein The output waveguide structure adopts an edge coupling design, and is a microprism array or a gradient refractive index lens integrated at the other end of the cover plate and symmetrical to the input waveguide structure.

4. The spatial light modulator according to claim 1, wherein The incident waveguide structure adopts a front coupling design and is an embossed grating, a volume grating or a microprism integrated on the upper surface or the lower surface of the cover plate.

5. The spatial light modulator according to claim 4, wherein The output waveguide structure adopts a front coupling design and is an embossed grating, a volume grating or a microprism integrated on the upper surface or the lower surface of the cover plate.

6. The spatial light modulator according to claim 1, wherein The liquid crystal layer is fixed between the cover plate and the substrate by optical adhesive.

7. The spatial light modulator according to claim 1, wherein The substrate is a silicon-based substrate, and the driving circuit is a semiconductor transistor array.

8. The spatial light modulator according to claim 1, wherein The cover plate is made of glass material, and the light beam reflection points in the cover plate are located at a plurality of preset positions corresponding to a plurality of independent working areas divided on the liquid crystal layer.

9. The spatial light modulator according to claim 8, wherein Pixel intervals are set between the multiple independent working areas.

10. The spatial light modulator according to claim 1, wherein The preset angle is calculated based on the refractive index of the cover plate and is greater than or equal to the critical angle of the cover plate.

11. A spatial light modulator self-test device, characterized in that: include: A laser light source, a photodetector, and a spatial light modulator according to any one of claims 1 to 10; The laser light source is arranged on the light-incoming side of the incident waveguide structure, and is used to emit detection laser; The incident waveguide structure is used to receive the detection laser and guide the detection laser into the cover plate at a preset angle; The cover plate is used to allow the detection laser to propagate in the form of total reflection inside the cover plate; The substrate is used to apply a regulating voltage to the liquid crystal layer; The liquid crystal layer is used to perform phase modulation on the detection laser light that is totally reflected and propagates to the liquid crystal layer in response to the control voltage; The output waveguide structure is used to guide the detection laser modulated by the liquid crystal layer from the cover plate to the free space and guide it to the photodetector; The photodetector is arranged on the light-emitting side of the output waveguide structure, and is used to detect the power of the modulated detection laser to determine the working state of the spatial light modulator.

12. The spatial light modulator self-testing device according to claim 11, wherein: The light beam reflection points in the cover plate are located at a plurality of preset positions corresponding to a plurality of independent working areas divided on the liquid crystal layer. Blazed grating patterns are sequentially displayed in the plurality of independent working areas, and the reflection angle of the detection laser is changed to perform functional detection on the plurality of independent working areas.

13. The spatial light modulator self-testing device according to claim 11, wherein: The length of the output waveguide structure from the liquid crystal layer is greater than the length of the input waveguide structure from the liquid crystal layer, so as to enhance the energy difference of the modulated detection laser when the spatial light modulator is in an operating state or a non-operating state.

14. The spatial light modulator self-testing device according to claim 11, wherein: The laser light source is a red light semiconductor laser with a wavelength of 635 nm.

15. The spatial light modulator self-testing device according to claim 11, wherein: The photodetector is a silicon-based balanced photodetector.

16. An optical computing device, characterized in that include: A laser light source, a digital micromirror, a photodetector, and a spatial light modulator according to any one of claims 1 to 10; The digital micromirror is disposed between the laser light source and the incident waveguide structure, and is used to spatially modulate the incident light emitted by the laser light source to form a light field including information to be calculated, and reflect the light field to the incident waveguide structure; The incident waveguide structure is used to receive the incident light modulated by the digital micromirror and guide the incident light into the cover plate at a preset angle; The cover plate is used to make the incident light propagate in the form of total reflection inside the cover plate, and the multiple reflection points of the reflection path correspond to the multiple independent working areas divided on the liquid crystal layer; The substrate is used to apply an independent control voltage to each working area of ​​the liquid crystal layer; The liquid crystal layer is used to perform phase modulation on the incident light region by region when the incident light propagates to each reflection point; The output waveguide structure is used to guide the incident light after multi-level phase modulation from the cover plate to free space; The photodetector is arranged on the light-emitting side of the output waveguide structure, and is used to output a detection signal representing a light calculation result based on the output light derived from the output waveguide structure.

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