Optical cross system based on silicon-based liquid crystal and control method

Abstract

The invention provides an optical cross system based on silicon-based liquid crystal and a control method, and relates to the field of optical elements, and the optical cross system comprises an optical fiber array, a micro lens array, a collimating lens, a polarization conversion module, a dispersion element, a focus lens group and a liquid crystal spatial light modulator. Optical signals are coupled through the micro-lens array, a divergence angle is compressed, and parallel light beams are formed through the double-agglutination collimating lens; the polarization conversion module separates the light beam into P / S polarized light and unifies the polarization state; the dispersion element separates light beams according to wavelength space, and the focus lens group forms an elliptical Gaussian light spot on the liquid crystal spatial light modulator; the liquid crystal spatial light modulator divides a light spot into a plurality of independent control areas in the long-axis direction, and single-wavelength multi-port output, power proportion regulation and control and monitoring signal extraction are achieved by dynamically modulating the reflection phase of each area. The control method comprises the steps of optical path processing, regionalized phase modulation and real-time monitoring feedback. According to the invention, flexible routing, power balance and lossless monitoring of wavelength channels can be realized.

Description

Technical Field

[0001] The present invention relates to the technical fields of optical communication and optical signal processing, and particularly to an optical cross-connect system based on liquid crystal on silicon and a control method therefor. Background Art

[0002] With the rapid development of technologies such as 5G communication, Internet of Things, and cloud computing, the demand of optical communication networks for transmission capacity, flexibility, and dynamic reconfigurability continues to climb. The traditional fixed optical network architecture has difficulty meeting the dynamic scheduling requirements of wavelength resources in multi-service scenarios, thus giving rise to the widespread application of reconfigurable optical add-drop multiplexer (ROADM) technology. As the core device of the ROADM system, the wavelength selective switch (WSS) realizes flexible allocation of optical layer resources and intelligent reconstruction of network topology by dynamically regulating the wavelength routing of optical signals, and has become one of the key technologies for constructing elastic optical networks.

[0003] The current mainstream WSS technologies are mainly based on microelectromechanical systems (MEMS), liquid crystal (LC), or silicon-based optics and other solutions. Among them, the MEMS technology has obvious shortcomings in terms of the scalability of wavelength channels (usually not exceeding 20 channels) and long-term stability due to the physical limitations of its mechanical structure. Although the LC solution improves the tunability to a certain extent, its response speed is slow (usually >10 ms), and the insertion loss is high (≥5 dB), making it difficult to meet the requirements of high-speed optical networks. Although silicon-based optical devices have made breakthroughs in integration, they face problems such as complex manufacturing processes and high costs, which limit their large-scale commercial use. In addition, as optical networks evolve towards flexible grid (Flexi-Grid) and ultra-dense wavelength division multiplexing (DWDM), the traditional WSS gradually shows deficiencies in terms of wavelength resolution, channel spacing adjustment accuracy, and multi-dimensional regulation capabilities.

[0004] In recent years, the WSS technology based on liquid crystal on silicon (LCoS) has gradually become a research hotspot in the field of optical communication due to its characteristics such as high resolution, low power consumption, fast response, and high integration. LCoS combines a liquid crystal layer with silicon-based reflective microdisplay technology, and precisely regulates the optical wavefront phase and polarization through a high-density pixel array (spacing accuracy reaching the sub-micron level), thereby realizing composite functions such as wavelength selection, power equalization, and multi-port switching in a single device. Compared with traditional solutions, LCoS-WSS has significant software-defined characteristics and can be compatible with new optical network architectures by upgrading control algorithms, becoming a key enabling technology to support the evolution of optical transmission networks towards elasticity and intelligence.

[0005] However, the existing LCOS-WSS solutions still face problems such as unbalanced spectral power, insufficient suppression of multi-channel crosstalk, and lack of real-time signal monitoring, and there is an urgent need to further improve performance through device structure optimization and system-level innovation. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide an optical cross-connect system based on liquid crystal on silicon and a control method to eliminate or improve one or more defects existing in the prior art, and solve the problems of unbalanced spectral power, insufficient suppression of multi-channel crosstalk, and lack of real-time signal monitoring in the prior art.

[0007] On the one hand, the present invention provides an optical cross-connect system based on liquid crystal on silicon, and the system includes: An optical fiber array, including an input port, a plurality of output ports, and at least one monitoring port, for input and output of optical signals; A microlens array, connected to the optical fiber array, for coupling the optical signal and reducing the divergence angle to obtain a divergent light beam; A collimating lens, for collimating the divergent light beam to form a parallel light beam; A polarization conversion module, for adjusting the polarization state of the parallel light beam; A dispersion element, for spatially separating the light beam adjusted by the polarization conversion module according to wavelength to obtain separated light beams of different wavelengths; A focusing lens group, for focusing the separated light beams of different wavelengths to different spatial positions of a liquid crystal spatial light modulator; A liquid crystal spatial light modulator, for receiving the light beams of each wavelength output by the focusing lens group, dynamically modulating the reflection phase of the received light beams of each wavelength based on a programmable pixel array, directing the light beams of each wavelength to a selected output port, and regulating the optical power ratio of the light reflected to each port; A monitoring port, for receiving a part of the reflected optical signal from the liquid crystal spatial light modulator for signal detection.

[0008] In some embodiments of the present invention, the system further includes: A first half-wave plate, disposed in the incident optical path of the liquid crystal spatial light modulator, for calibrating the polarization direction of the reflected light to match the modulation requirements.

[0009] In some embodiments of the present invention, the collimating lens adopts a double-glued lens system based on a telescope structure, including a first convex lens and a second convex lens arranged in sequence along the optical path: The first convex lens has a short focal length and is used to compress the waist radius of the divergent light beam; The second convex lens has a long focal length and is used to expand the light beam processed by the first convex lens.

[0010] In some embodiments of the present invention, it further includes: The first convex lens compresses the waist radius of the divergent beam, and the transformation of the beam parameters after compression satisfies the following formula: ; The second convex lens expands the beam processed by the first convex lens, and the maximum beam expansion multiple of the waist radius of the output beam satisfies the following formula: ; The parameter configuration of the doublet lens system simultaneously satisfies the following formula: ; Wherein, represents the distance between the waist of the divergent beam and the first convex lens; represents the distance between the waist of the compressed beam and the first convex lens; represents the focal length of the first convex lens; represents the Rayleigh length of the divergent beam; represents the waist radius of the beam processed by the first convex lens; represents the waist radius of the beam output by the second convex lens; represents the focal length of the second convex lens; represents the distance between the waist of the beam output by the second convex lens and the second convex lens; represents the distance between the first convex lens and the second convex lens.

[0011] In some embodiments of the present invention, the polarization conversion module further includes: A polarization beam splitting prism for separating the parallel beam into a first polarized light and a second polarized light according to the polarization direction, wherein the first polarized light is directly transmitted and the second polarized light is reflected to the first optical path; A second half-wave plate disposed in the first optical path for rotating the polarization direction of the second polarized light by 90° to be consistent with the first polarized light; A right-angle prism for receiving the second polarized light rotated by the second half-wave plate and reflecting it to a second optical path parallel to the first polarized light, so that the two beams of light enter the dispersion element with the same polarization state.

[0012] In some embodiments of the present invention, the dispersion element is a diffraction grating, and the diffraction grating separates the incident light with the same polarization state into a plurality of monochromatic lights with different wavelengths, and each monochromatic light exits at a different diffraction angle to form a wavelength channel with a spatial distribution.

[0013] In some embodiments of the present invention, the grating period of the diffraction grating satisfies the following grating diffraction equation: ; Among them, represents the grating period of the diffraction grating; represents the angle between the incident light and the grating normal; represents the angle between the diffracted light and the grating normal; represents the wavelength of the incident light; represents the diffraction order.

[0014] In some embodiments of the present invention, the liquid crystal spatial light modulator dynamically modulates the reflection phase of each wavelength beam received based on a programmable pixel array, including: The relationship between the deflection angle of the liquid crystal molecules of each pixel and the driving voltage satisfies the following formula: ; Among them, represents the deflection angle of the liquid crystal molecules; represents the driving voltage; represents the threshold voltage; represents the saturation voltage; The relationship between the phase change amount of the reflected light and the deflection angle of the liquid crystal molecules satisfies the following formula: ; Among them, represents the phase change amount of the reflected light; represents the thickness of the liquid crystal layer; represents the wavelength of the incident light; represents the correspondence between the deflection angle of the liquid crystal molecules and the extraordinary refractive index; represents the ordinary refractive index; The spot formed by the focusing lens group on the liquid crystal spatial light modulator is in an elliptical Gaussian distribution, as shown in the formula: ; Among them, and respectively represent the waist radii in the focusing directions and respectively.

[0015] In some embodiments of the present invention, the liquid crystal spatial light modulator divides the long axis direction of the spot into multiple independently controllable regions, and by adjusting the phase change amounts of the respective independently controllable regions, reflects the same wavelength beam to selected different output ports and simultaneously controls the optical power ratios of the light reflected to each output port.

[0016] On the other hand, the present invention provides an optical cross control method based on liquid crystal on silicon, and the method includes the following steps: Receiving an optical signal through an optical fiber array and distributing the optical signal to a plurality of output ports and at least one monitoring port; Couple the optical signal using a microlens array and reduce the divergence angle to generate a divergent light beam; Collimate the divergent light beam using a collimating lens to generate a parallel light beam; Adjust the polarization state of the parallel light beam through a polarization conversion module to form a uniformly polarized light beam; Use a dispersion element to spatially separate the uniformly polarized light beam by wavelength to generate multiple wavelength-channel light beams; Focus each wavelength-channel light beam to different spatial positions on a liquid crystal spatial light modulator through a focusing lens group to form spatially distributed light spots; Divide the light spot corresponding to each wavelength into multiple independently controllable regions along the long-axis direction; independently set a driving voltage for each independently controllable region to generate a corresponding reflected light phase change amount; by regulating the phase change amounts of each independently controllable region, direct each wavelength light beam to a selected output port and dynamically adjust the optical power ratio reflected to each output port; Select the reflected light of a specific independently controllable region and introduce it into the monitoring port for performance analysis, and dynamically optimize the control parameters of the liquid crystal spatial light modulator according to the analysis results.

[0017] The present invention provides an optical cross-connect system and control method based on liquid crystal on silicon, including an optical fiber array, a microlens array, a collimating lens, a polarization conversion module, a dispersion element, a focusing lens group, and a liquid crystal spatial light modulator. The optical signal is coupled by the microlens array and the divergence angle is compressed, and a parallel light beam is formed by a doublet collimating lens; the polarization conversion module separates the light beam into P / S polarized light and unifies the polarization state; the dispersion element spatially separates the light beam by wavelength, and the focusing lens group forms an elliptical Gaussian light spot on the liquid crystal spatial light modulator; the liquid crystal spatial light modulator divides the long-axis direction of the light spot into multiple independently controllable regions, and realizes single-wavelength multi-port output, power ratio regulation, and monitoring signal extraction by dynamically modulating the reflection phase of each region. The control method includes optical path processing, regionalized phase modulation, and real-time monitoring feedback. The present invention can achieve flexible routing, power balance, and lossless monitoring of wavelength channels, and solves the problems of spectral power imbalance and lack of real-time monitoring of traditional wavelength selective switches.

[0018] The additional advantages, objects, and features of the present invention will be partially described in the following description, and will become partially apparent to those of ordinary skill in the art after studying the following text, or can be learned from the practice of the present invention. The objects and other advantages of the present invention can be achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0019] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and the above and other objectives achievable with the present invention will be more clearly understood from the following detailed description. Description of the Drawings

[0020] The drawings described herein are used to provide a further understanding of the present invention and form a part of this application, and do not constitute a limitation to the present invention. In the drawings: Figure 1 It is a schematic three-dimensional structure diagram of the overall optical path of a liquid crystal on silicon-based optical cross-connect system in an embodiment of the present invention.

[0021] Figure 2 It is a schematic plan view of the optical path of a liquid crystal on silicon-based optical cross-connect system in different perspectives in an embodiment of the present invention.

[0022] Figure 3 It is a schematic diagram of the working principle of a collimating lens in an embodiment of the present invention.

[0023] Figure 4 It is a schematic diagram of the structure and working principle of a polarization conversion module in an embodiment of the present invention.

[0024] Reference Numerals in the Drawings: (1) Fiber Optic Array; (2) Microlens Array; (3) Collimating Lens; (4) Polarization Conversion Module; (5) Dispersion Element; (6) Focusing Lens Group; (7) First Half-Wave Plate; (8) Liquid Crystal Spatial Light Modulator; (9) Polarizing Beam Splitter Prism; (10) Second Half-Wave Plate; (11) Right-Angle Prism. Detailed Embodiments

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the embodiments and the drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute a limitation to the present invention.

[0026] Herein, it should also be noted that in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0027] It should be emphasized that the term "comprising / including" when used herein refers to the presence of features, elements, steps, or components, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0028] Here, it should also be noted that, unless otherwise specified, the term "connection" in this article can not only refer to direct connection, but also indirect connection with intermediates.

[0029] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0030] It should be emphasized here that the step labels mentioned below do not limit the order of the steps. Instead, it should be understood that the steps can be executed in the order mentioned in the embodiments, or different from the order in the embodiments, or several steps can be executed simultaneously.

[0031] To solve the problems of unbalanced spectral power, insufficient suppression of multi-channel crosstalk, and lack of real-time signal monitoring existing in the prior art, the present invention provides an optical cross-connect system based on liquid crystal on silicon, as Figure 1 shown, the system includes: An optical fiber array (1), including an input port, a plurality of output ports, and at least one monitoring port, for input and output of optical signals.

[0032] A microlens array (2), connected to the optical fiber array (1), for coupling optical signals and reducing the divergence angle to obtain a divergent light beam.

[0033] A collimating lens (3), for collimating the divergent light beam processed by the microlens array (2) to form a parallel light beam.

[0034] A polarization conversion module (4), for adjusting the polarization state of the parallel light beam.

[0035] A dispersion element (5), for spatially separating the light beam adjusted by the polarization conversion module (4) according to wavelength to obtain separated light beams of different wavelengths.

[0036] A focusing lens group (6), for focusing the separated light beams of different wavelengths to different spatial positions of the liquid crystal spatial light modulator (8).

[0037] A liquid crystal spatial light modulator (8), for receiving the light beams of each wavelength output by the focusing lens group (6), dynamically modulating the reflection phase of the received light beams of each wavelength based on a programmable pixel array, directing the light beams of each wavelength to a selected output port, and regulating the optical power ratio of the light reflected to each port.

[0038] A monitoring port, for receiving a part of the reflected optical signal from the liquid crystal spatial light modulator (8) for signal detection.

[0039] In some embodiments, the system further includes a first half-wave plate (7) disposed in the incident optical path of the liquid crystal spatial light modulator (8) for further calibrating the polarization direction of the reflected light to match the modulation requirements.

[0040] As Figure 2 shown, it is a dual-view schematic diagram of the optical cross-connect system of the present invention. Among them, the upper part is the schematic diagram of the optical path under the YZ plane, and the lower part is the schematic diagram of the optical path under the XZ plane.

[0041] The fiber optic array is usually of the 1×N type, that is, 1 input port and N output ports. Preferably, in the present invention, one of the output ports is used as the monitoring port.

[0042] The microlens array is connected to the fiber optic array and can be understood as a group of miniature magnifying glasses, with each small lens precisely aligned with one fiber optic. The divergent light beam output by the fiber optic array is refocused through the curvature of the lens surface to achieve optical signal coupling. While concentrating the light, the specific curvature of the lens can make the incident light at different angles emit in a more parallel direction, so the light beam is preliminarily collimated and the divergence angle is reduced.

[0043] The collimating lens precisely collimates the divergent light beam preliminarily collimated by the microlens array and corrects the divergent light beam into a parallel light beam.

[0044] In some embodiments, as Figure 3 shown, the collimating lens adopts a doublet lens system based on a telescope structure, including a first convex lens and a second convex lens arranged in sequence along the optical path. Among them, the first convex lens has a short focal length and is used to compress the waist radius of the divergent light beam; the second convex lens has a long focal length and is used to expand the light beam processed by the first convex lens.

[0045] The first convex lens of the doublet lens system first compresses the waist radius of the divergent light beam, and the transformation of the beam parameters after compression satisfies the following formula (1): ; (1) Among them, represents the distance from the waist of the divergent light beam to the first convex lens; represents the distance from the waist of the compressed light beam to the first convex lens; represents the focal length of the first convex lens; represents the Rayleigh length of the divergent light beam.

[0046] The second convex lens then expands the light beam processed by the first convex lens. Among them, the maximum expansion multiple of the waist radius of the output light beam satisfies the following formula (2): ; (2) Among them, represents the beam waist radius of the light beam after being processed by the first convex lens; represents the beam waist radius of the output light beam of the second convex lens; represents the focal length of the second convex lens.

[0047] The parameter configuration of the doublet lens system simultaneously satisfies the following formula (3): ; (3) wherein, represents the distance between the beam waist of the output light beam of the second convex lens and the second convex lens; represents the distance between the first convex lens and the second convex lens.

[0048] After being processed by the above-mentioned doublet lens system, the maximum output light beam waist radius can be achieved, and the beam waist position of the output light beam is located on the focal plane of the second convex lens, making the output light beam the most parallel at this position, that is, the divergence angle is the smallest, and the spot shape is the roundest and most regular.

[0049] In some embodiments of the present invention, as Figure 4 shown, the polarization conversion module further includes a polarization beam splitting prism (9), a second half-wave plate (10) and a right-angle prism (11). Specifically: The polarization beam splitting prism uses a birefringent crystal such as yttrium vanadate (YVO4) to separate the parallel light beam into a first polarized light and a second polarized light according to the polarization direction. Among them, the first polarized light (P-polarized light, corresponding to the TE mode in the waveguide) is directly transmitted, and the second polarized light (S-polarized light, corresponding to the TM mode in the waveguide) is reflected to the first optical path. Among them, the P-polarized light refers to the direction of the electric vector vibration parallel to the incident plane; the S-polarized light refers to the direction of the electric vector vibration perpendicular to the incident plane, that is, perpendicular to the plane formed by the optical path and the interface normal.

[0050] The second half-wave plate is arranged in the first optical path and is used to rotate the polarization direction of the second polarized light by 90° to be consistent with the first polarized light.

[0051] The right-angle prism is used to receive the second polarized light rotated by the second half-wave plate and reflect it to the second optical path parallel to the first polarized light, so that the two light beams are incident on the dispersion element with the same polarization state.

[0052] In some embodiments, the dispersion element usually uses a diffraction grating. Specifically, the diffraction grating separates the incident light with the same polarization state processed by the polarization conversion module into multiple monochromatic lights with different wavelengths, and each monochromatic light exits at a different diffraction angle, forming a wavelength channel with a spatial distribution.

[0053] In some embodiments, the grating period of the diffraction grating satisfies the following grating diffraction equation, such as formula (4): ; (4) Among them, represents the grating period of the diffraction grating; represents the angle between the incident light and the grating normal; represents the angle between the diffracted light and the grating normal; represents the wavelength of the incident light; represents the diffraction order.

[0054] In some embodiments, the focusing lens group adopts a doublet lens system for focusing the separated light beams of different wavelengths to different spatial positions of the liquid crystal spatial light modulator.

[0055] The liquid crystal spatial light modulator (LCoS) is a programmable optical modulation device based on CMOS technology, and its core structure is composed of a silicon substrate integrated with a driving circuit, a liquid crystal cell, and a high-reflectivity electrode layer. When an external electrical signal is applied to the CMOS circuit, each pixel can be independently applied with an accurate voltage, and the optical phase modulation is achieved through the orientation change of the voltage-sensitive liquid crystal molecules. Specifically, when the applied voltage exceeds the threshold voltage, the deflection angle of the liquid crystal molecules follows a non-linear response curve, and finally the reflected light generates a phase delay amount related to the deflection angle, which is jointly determined by the liquid crystal layer thickness, the extraordinary refractive index, and the wavelength of the incident light.

[0056] In some embodiments, the relationship between the deflection angle of the liquid crystal molecules of each pixel and the driving voltage satisfies the following formula (5): ; (5) Among them, represents the deflection angle of the liquid crystal molecules; represents the driving voltage; represents the threshold voltage; represents the saturation voltage.

[0057] In some embodiments, the relationship between the phase change amount of the reflected light and the deflection angle of the liquid crystal molecules satisfies the following formula (6): ; (6) Among them, represents the phase change amount of the reflected light; represents the liquid crystal layer thickness; represents the wavelength of the incident light; represents the corresponding relationship between the deflection angle of the liquid crystal molecules and the extraordinary refractive index; represents the ordinary refractive index.

[0058] In formula 6, the corresponding relationship between the deflection angle of the liquid crystal molecules and the extraordinary refractive index also satisfies the following formula (7): ; (7) Among them, and respectively represent the ordinary refractive index and the extraordinary refractive index without voltage applied.

[0059] Since the incident light is an ideal Gaussian beam, when passing through the focusing lens group, because the focusing lens group has focusing ability only in a single direction (such as the x direction) and has no optical power in the orthogonal direction (such as the y direction), the beam will present an asymmetric transformation in two dimensions. In the focusing direction (x-axis), the refractive effect of the focusing lens group will reduce the beam waist radius to 1 / M times of the original value (M is the magnification), and at the same time, the divergence angle in this direction will increase by M times; in the non-focusing direction (y-axis), the beam parameters maintain the original Gaussian characteristics before incidence. This selective transformation causes the output light intensity distribution to present an elliptical Gaussian characteristic, and its mathematical expression is as shown in formula (8): ; (8) Wherein, and respectively represent the beam waist radii in the focusing direction and respectively.

[0060] This controllable asymmetric beam shaping characteristic is exactly the physical basis for realizing wavelength channel spatial separation and LCoS regional modulation in the optical cross-connect system: the expansion of the long axis (y direction) of the ellipse matches the multi-wavelength arrangement requirement of the dispersion dimension, and the short axis (x direction) ensures the accurate positioning of each wavelength spot in the port dimension.

[0061] Since the spot intensity is Gaussian distributed, there are naturally gradient differences in the optical power carried by each region (the light intensity is the largest in the central region and decreases towards the edge region). Therefore, the liquid crystal spatial light modulator divides the long axis direction of the spot into multiple independently controllable regions, and by applying differential voltage signals to each independently controllable region, the phase change amount of the corresponding liquid crystal cells is precisely regulated, so that a beam of the same wavelength can be decomposed into multiple independently controllable sub-beams. Exemplarily, the central high-power region mainly carries service signals and can be directionally reflected to the output port; the edge low-power region is allocated to the monitoring port (such as extracting 1% - 5% of the power), and the key parameters of the signal, such as the optical signal-to-noise ratio (Optical Signal-to-Noise Ratio, OSNR), bit error rate (Bit Error Rate, BER), wavelength offset, modulation error, etc., can be analyzed in real time without affecting the main signal transmission, realizing lossless monitoring of the service.

[0062] The present invention also provides an optical cross-connect control method based on liquid crystal on silicon, and the steps of this method are implemented by an optical cross-connect system based on liquid crystal on silicon, including the following steps S101 - S108: Step S101: Receive optical signals through an optical fiber array and distribute the optical signals to multiple output ports and at least one monitoring port.

[0063] Step S102: Use a microlens array to couple the optical signal and reduce the divergence angle to generate a divergent light beam.

[0064] Step S103: Collimate the divergent light beam using a collimating lens to generate a parallel light beam.

[0065] Step S104: Adjust the polarization state of the parallel light beam through a polarization conversion module to form a uniformly polarized light beam.

[0066] Step S105: Use a dispersion element to spatially separate the uniformly polarized light beam by wavelength to generate multiple wavelength-channel light beams.

[0067] Step S106: Focus each wavelength-channel light beam to different spatial positions on a liquid crystal spatial light modulator through a focusing lens group to form spatially distributed light spots.

[0068] Step S107: Divide the light spot corresponding to each wavelength into multiple independently controllable regions along the long axis direction; independently set a driving voltage for each independently controllable region to generate a corresponding reflected light phase change amount; by regulating the phase change amounts of each independently controllable region, direct each wavelength light beam to a selected output port and dynamically adjust the optical power ratio of the light reflected to each output port.

[0069] Step S108: Select the reflected light of a specific independently controllable region and introduce it into a monitoring port for performance analysis, and dynamically optimize the control parameters of the liquid crystal spatial light modulator according to the analysis results.

[0070] Corresponding to the above method, the present invention also provides an electronic device, which includes a computer device. The computer device includes a processor and a memory. The memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the electronic device implements the steps of the method described above.

[0071] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described above are implemented.

[0072] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, the detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present invention.

[0073] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or replace the features of other embodiments.

[0074] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A liquid crystal on silicon-based optical cross-connect system, characterized in that, The system includes: An optical fiber array, including an input port, a plurality of output ports, and at least one monitoring port, for input and output of optical signals; A microlens array, connected to the optical fiber array, for coupling the optical signals and reducing the divergence angle to obtain a divergent light beam; A collimating lens, for collimating the divergent light beam to form a parallel light beam; A polarization conversion module, for adjusting the polarization state of the parallel light beam; A dispersion element, for spatially separating the light beam adjusted by the polarization conversion module according to wavelengths to obtain separated light beams of different wavelengths; A focusing lens group, for focusing the separated light beams of different wavelengths to different spatial positions of a liquid crystal spatial light modulator; A liquid crystal spatial light modulator, for receiving the light beams of each wavelength output by the focusing lens group, dynamically modulating the reflection phase of the received light beams of each wavelength based on a programmable pixel array, directing the light beams of each wavelength to a selected output port by reflection, and regulating the optical power ratio of the light reflected to each port; A monitoring port, for receiving a part of the reflected optical signal from the liquid crystal spatial light modulator for signal detection.

2. The liquid crystal on silicon-based optical cross-connect system according to claim 1, wherein The system further includes: A first half-wave plate, arranged in the incident optical path of the liquid crystal spatial light modulator, for calibrating the polarization direction of the reflected light to match the modulation requirement.

3. The liquid crystal on silicon-based optical cross-connect system according to claim 1, wherein The collimating lens adopts a double-glued lens system based on a telescope structure, including a first convex lens and a second convex lens arranged in sequence along the optical path: The first convex lens has a short focal length and is used for compressing the waist radius of the divergent light beam; The second convex lens has a long focal length and is used for expanding the light beam processed by the first convex lens.

4. The liquid crystal on silicon-based optical cross-connect system according to claim 3, wherein It further includes: The first convex lens compresses the waist radius of the divergent light beam, and the parameter transformation of the compressed light beam satisfies the following formula: ； The second convex lens expands the light beam processed by the first convex lens, and the maximum expansion multiple of the waist radius of the output light beam satisfies the following formula: ； The parameter configuration of the double-glued lens system simultaneously satisfies the following formula: ； Among them, represents the distance between the waist of the divergent light beam and the first convex lens; represents the distance between the waist of the compressed light beam and the first convex lens; represents the focal length of the first convex lens; represents the Rayleigh length of the divergent light beam; represents the waist radius of the light beam after being processed by the first convex lens; represents the waist radius of the light beam output by the second convex lens; represents the focal length of the second convex lens; represents the distance between the waist of the light beam output by the second convex lens and the second convex lens; represents the distance between the first convex lens and the second convex lens.

5. The liquid crystal on silicon-based optical cross-connect system according to claim 1, wherein The polarization conversion module further includes: A polarization beam splitting prism, for splitting the parallel light beam into a first polarized light and a second polarized light according to the polarization direction, wherein the first polarized light is directly transmitted, and the second polarized light is reflected to a first optical path; A second half-wave plate, arranged in the first optical path, for rotating the polarization direction of the second polarized light by 90° to be consistent with the first polarized light; A right-angle prism, for receiving the second polarized light rotated by the second half-wave plate and reflecting it to a second optical path parallel to the first polarized light, so that the two light beams enter the dispersion element with the same polarization state.

6. The liquid crystal on silicon-based optical cross-connect system according to claim 1, wherein The dispersion element is a diffraction grating, and the diffraction grating separates the incident light of the same polarization state into a plurality of monochromatic lights of different wavelengths, and each monochromatic light exits at a different diffraction angle to form a wavelength channel with a spatial distribution.

7. The liquid crystal on silicon-based optical cross-connect system according to claim 6, wherein The grating period of the diffraction grating satisfies the following grating diffraction equation: ； Wherein, represents the grating period of the diffraction grating; represents the angle between the incident light and the grating normal; represents the angle between the diffracted light and the grating normal; represents the wavelength of the incident light; represents the diffraction order.

8. The liquid crystal on silicon based optical cross-connect system according to claim 1, wherein The liquid crystal spatial light modulator dynamically modulates the reflection phase of the received light beams of each wavelength based on a programmable pixel array, including: The relationship between the deflection angle of the liquid crystal molecules of each pixel and the driving voltage satisfies the following formula: ； Among them, represents the deflection angle of the liquid crystal molecules; represents the driving voltage; represents the threshold voltage; represents the saturation voltage; The relationship between the phase change amount of the reflected light and the deflection angle of the liquid crystal molecules satisfies the following formula: ； Among them, represents the phase change amount of the reflected light; represents the liquid crystal layer thickness; represents the wavelength of the incident light; represents the corresponding relationship between the deflection angle of the liquid crystal molecules and the extraordinary refractive index; represents the ordinary refractive index; The light spot formed by the focusing lens group on the liquid crystal spatial light modulator is in an elliptical Gaussian distribution, as shown in the formula: ； Among them, and respectively represent the focusing direction and of the waist radius.

9. The liquid crystal on silicon based optical cross-connect system according to claim 8, characterized in that The liquid crystal spatial light modulator divides the long axis direction of the light spot into multiple independent control regions. By regulating the phase change amount of each independent control region, the light beam of the same wavelength is reflected to selected different output ports, and at the same time, the optical power ratio reflected to each output port is controlled.

10. A method for optical cross control based on liquid crystal on silicon, characterized in that, The method includes the following steps: Receiving an optical signal through an optical fiber array and distributing the optical signal to multiple output ports and at least one monitoring port; Coupling the optical signal by using a microlens array and reducing the divergence angle to generate a divergent light beam; Collimating the divergent light beam by using a collimating lens to generate a parallel light beam; Adjusting the polarization state of the parallel light beam through a polarization conversion module to form a beam with unified polarization; Using a dispersion element to spatially separate the beam with unified polarization according to wavelengths to generate multiple wavelength channel light beams; Focusing each wavelength channel light beam to different spatial positions of the liquid crystal spatial light modulator through a focusing lens group to form a spatially distributed light spot; Dividing the light spot corresponding to each wavelength along the long axis direction into multiple independent control regions; independently setting a driving voltage for each independent control region to generate a corresponding phase change amount of the reflected light; by regulating the phase change amount of each independent control region, directing each wavelength light beam to a selected output port and dynamically adjusting the optical power ratio reflected to each output port; Selecting the reflected light of a specific independent control region, introducing it into the monitoring port for performance analysis, and dynamically optimizing the control parameters of the liquid crystal spatial light modulator according to the analysis results.

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