LCOS linearity correction method based on cubesat laser communication terminal

Abstract

The invention provides an LCOS linearity correction method based on a cubesat laser communication terminal, and relates to the technical field of communication, and the method comprises the steps: obtaining the corresponding relation between the driving voltage and phase response of an LCOS device; generating an initial correction curve; performing least square fitting according to driving voltage segments, and dynamically adjusting segment points until the slope difference of boundary points of adjacent segment curves is smaller than a preset threshold value; establishing a mapping relation table between the target phase value and the driving voltage; and temperature parameters are collected in real time for compensation and correction. According to the invention, the phase modulation precision of the LCOS is improved, and the on-orbit working stability of the system is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular, to an LCOS linearity correction method based on a CubeSat laser communication terminal. Background Art

[0002] In a CubeSat laser communication terminal, a liquid crystal spatial light modulator (LCOS) is used as a key device to achieve precise modulation and control of laser beams. By changing the applied driving voltage, the LCOS device can adjust the alignment direction of liquid crystal molecules, thereby changing the phase of incident light and realizing wavefront control of the light beam. Ideally, the driving voltage of the LCOS device and the actual phase response should have a linear relationship. However, in practical applications, due to the physical properties of liquid crystal materials, device manufacturing process errors, and temperature changes, there is usually a non-linear relationship between the driving voltage and the phase response. This non-linear relationship will lead to a decrease in wavefront control accuracy and affect the performance of the laser communication system.

[0003] The existing methods for correcting the non-linear characteristics of LCOS have the following deficiencies: First, traditional correction methods usually adopt a single polynomial fitting or look-up table method, which is difficult to balance high-precision fitting and calculation efficiency within the full voltage range. Especially in the region where the non-linear characteristics of the LCOS device change greatly, fitting errors are likely to occur. Second, the existing correction algorithms lack effective optimization processing for the boundary points of piecewise fitting, resulting in discontinuity or slope mutation between adjacent segments, which affects the smoothness and accuracy of phase modulation. Third, the CubeSat in orbit faces a complex and changing space temperature environment, while the existing correction methods often ignore the influence of temperature changes on the phase response characteristics of LCOS and lack a real-time temperature compensation mechanism, making it difficult to ensure the phase control accuracy during on-orbit operation, and further affecting the stability and reliability of the laser communication link. Summary of the Invention

[0004] The embodiments of the present invention provide an LCOS linearity correction method based on a CubeSat laser communication terminal, which can solve the problems in the prior art.

[0005] In the first aspect of the embodiments of the present invention,

[0006] Obtain the correspondence between the driving voltage and the actual phase response of the LCOS device in the CubeSat laser communication terminal; generate an initial correction curve of the driving voltage and the actual phase response of the LCOS device according to the correspondence; [[ID=2,4]]

[0007] Segment the initial calibration curve according to the driving voltage, perform least squares fitting on the phase response within each driving voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference between the boundary points of adjacent segmented fitting curves until the slope difference at the boundary points of adjacent segmented fitting curves is less than a preset slope threshold to obtain an optimized segmented fitting curve;

[0008] Use the optimized segmented fitting curve as a reference curve and establish a mapping relationship table between the target phase value and the driving voltage of the LCOS device by means of two-way search;

[0009] During the operation of the cube satellite laser communication terminal, collect the temperature parameters of the LCOS device in real time, perform temperature compensation calibration on the mapping relationship table according to the temperature parameters to obtain a temperature-compensated mapping relationship table, and apply a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relationship table.

[0010] The method further includes realizing optical path displacement compensation based on the fiber automatic alignment of the LCOS device:

[0011] Display blazed gratings with different directions and periods on the LCOS device to generate multiple diffracted beams, control the multiple diffracted beams to perform traversal scanning along a spiral path, and when any one of the diffracted beams is detected, obtain the relative displacement azimuth angle between the optical fiber and the light spot;

[0012] Determine a fan-shaped search area according to the relative displacement azimuth angle, gradually expand the search range within the fan-shaped search area for energy detection, use the position of the maximum energy detected in each fan-shaped search area as the search starting point for the next fan-shaped area, and when the local maximum value of the light intensity is detected, obtain the relative displacement intermediate value between the optical fiber and the light spot;

[0013] Based on the relative displacement azimuth angle and the relative displacement intermediate value, perform skip search between different diffraction orders to obtain the absolute value of the relative displacement;

[0014] Determine the optical fiber position according to the relative displacement azimuth angle and the absolute value of the relative displacement, and perform local search within the neighborhood of the optical fiber position with a fine step size smaller than the initial step size until the compensation position with the best optical fiber coupling efficiency is obtained;

[0015] Display the corresponding blazed grating pattern on the LCOS device according to the compensation position to realize optical path displacement compensation.

[0016] Performing skip search between different diffraction orders based on the relative displacement azimuth angle and the relative displacement intermediate value includes:

[0017] Set multiple search positions by incrementing the relative displacement median value in integer multiples, perform light intensity detection within the neighborhood of each search position, and when the maximum light intensity is detected, obtain the absolute value of the relative displacement between the optical fiber and the light spot.

[0018] Segment the initial correction curve according to the driving voltage, perform least-squares fitting on the phase response within each driving voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves, including:

[0019] Obtain the phase response curve of the LCOS device under the action of the driving voltage, calculate the second derivative of the phase response curve, determine the initial segmentation points according to the extreme points of the second derivative, and divide the phase response curve into multiple initial segmented intervals;

[0020] For the phase response data within each segmented interval in the initial segmented intervals, establish an nth-order polynomial fitting model, and use the least-squares method to solve the coefficients of the nth-order polynomial fitting model to obtain the segmented fitting function corresponding to each segmented interval;

[0021] Calculate the left slope and the right slope at the segmentation point of two adjacent segmented fitting functions, obtain the difference between the left slope and the right slope, where the left slope is the first derivative value of the segmented fitting function on the left side of the segmentation point, and the right slope is the first derivative value of the segmented fitting function on the right side of the segmentation point;

[0022] When the slope difference at any segmentation point is greater than the preset slope threshold, determine the offset direction of the segmentation point according to the magnitude of the slope difference and the relative magnitude relationship between the left slope and the right slope, and move the segmentation point by a preset step length in the determined offset direction, where the preset step length is proportional to the slope difference;

[0023] Repeat the least-squares fitting and slope difference calculation for the segmented intervals divided by the newly moved segmentation points until the slope differences at all segmentation points are less than the preset threshold or the preset number of iterations is reached, to obtain the final segmented fitting function.

[0024] Use the optimized segmented fitting curve as the reference curve, and establish a mapping relationship table between the target phase value and the driving voltage of the LCOS device by means of two-way search, including:

[0025] Obtain the optimized segmented fitting curve of the LCOS device, use the segmented fitting curve as the reference curve, and the reference curve represents the corresponding relationship between the driving voltage and the phase response of the LCOS device;

[0026] Divide the target phase modulation range of the LCOS device into M discrete phase points, where M is a positive integer, and the intervals between adjacent discrete phase points are equal;

[0027] For each of the discrete phase points, set an initial search interval within the driving voltage range of the reference curve. The upper boundary of the initial search interval is the maximum driving voltage, and the lower boundary is the minimum driving voltage;

[0028] Perform a two-way search using the bisection method within the initial search interval, including: calculating the phase value corresponding to the midpoint of the current search interval, comparing the phase value with the target phase point. When the phase value is greater than the target phase point, update the upper boundary of the search interval to the current midpoint. When the phase value is less than the target phase point, update the lower boundary of the search interval to the current midpoint;

[0029] Determine whether the difference between the upper boundary and the lower boundary of the current search interval is less than a preset precision threshold. When it is less than the preset precision threshold, take the midpoint of the current search interval as the driving voltage value corresponding to the discrete phase point;

[0030] Repeat the two-way search process for all discrete phase points to establish a one-to-one correspondence between the discrete phase points and the driving voltages, and generate a phase-voltage mapping table for the LCOS device.

[0031] Perform temperature compensation and correction on the mapping relationship table according to the temperature parameter to obtain a temperature-compensated mapping relationship table, and apply corresponding driving voltages to the LCOS device according to the temperature-compensated mapping relationship table, including:

[0032] Take the phase response at the reference temperature as a reference, calculate the offset of the phase response under other temperature conditions relative to the phase response at the reference temperature to obtain the phase offset corresponding to each sampling temperature point;

[0033] According to the correspondence between the temperature points and the phase offsets, establish a linear relationship model between the temperature change and the phase offset to obtain the temperature-phase compensation coefficient;

[0034] During the operation of the LCOS device, the current operating temperature of the LCOS device is collected in real time through a temperature sensor, and the phase compensation value is calculated according to the temperature difference between the current operating temperature and the reference temperature;

[0035] Correct the phase-voltage mapping table of the LCOS device according to the phase compensation value, including: subtracting the phase compensation value from the target phase value to obtain the compensated phase value, and finding the corresponding driving voltage from the phase-voltage mapping table according to the compensated phase value;

[0036] Apply the obtained drive voltage to the LCOS device to achieve precise phase modulation of the LCOS device under different temperature conditions.

[0037] In the second aspect of the embodiments of the present invention, a LCOS linearity correction system based on a cube satellite laser communication terminal is provided, including:

[0038] A first unit, configured to obtain the correspondence between the drive voltage and the actual phase response of the LCOS device in the cube satellite laser communication terminal; generate an initial correction curve of the drive voltage and the actual phase response of the LCOS device according to the correspondence;

[0039] A second unit, configured to segment the initial correction curve according to the drive voltage, perform least squares fitting on the phase response within each drive voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves until the slope difference at the boundary points of adjacent segmented fitting curves is less than a preset slope threshold, so as to obtain an optimized segmented fitting curve;

[0040] A third unit, configured to use the optimized segmented fitting curve as a reference curve and establish a mapping relationship table between the target phase value and the drive voltage of the LCOS device by using a two-way lookup method;

[0041] A fourth unit, configured to, during the operation of the cube satellite laser communication terminal, collect the temperature parameters of the LCOS device in real time, perform temperature compensation correction on the mapping relationship table according to the temperature parameters to obtain a temperature-compensated mapping relationship table, and apply a corresponding drive voltage to the LCOS device according to the temperature-compensated mapping relationship table.

[0042] In the third aspect of the embodiments of the present invention,

[0043] There is provided an electronic device, including:

[0044] A processor;

[0045] A memory for storing instructions executable by the processor;

[0046] Wherein, the processor is configured to call the instructions stored in the memory to execute the method described above.

[0047] In the fourth aspect of the embodiments of the present invention,

[0048] There is provided a computer-readable storage medium, on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the method described above is implemented.

[0049] The beneficial effects of this application are as follows:

[0050] By piecewise fitting the relationship between the driving voltage and the actual phase response of the LCOS device and dynamically adjusting the piecewise points, the problem of phase jitter caused by the discontinuity of the calibration curve in the traditional calibration method is solved, and the accuracy and stability of phase modulation are improved.

[0051] A mapping relationship table between the target phase value and the driving voltage is established by using a two-way search method, which simplifies the real-time operation complexity, reduces the consumption of computing resources, is particularly suitable for the CubeSat platform with limited resources, and improves the system response speed and working efficiency.

[0052] The temperature parameters are collected in real time and dynamically compensated and calibrated, which effectively solves the influence of the space environment temperature change on the LCOS phase modulation characteristics, enhances the adaptability and reliability of the laser communication terminal in the complex space environment, and ensures the stability of the communication link. Description of the Drawings

[0053] Figure 1 It is a schematic flowchart of the LCOS linearity calibration method based on the CubeSat laser communication terminal according to the embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of a common inter-satellite laser communication terminal according to the embodiment of the present invention;

[0055] Figure 3 It is a simplified schematic diagram of the receiving module in a common inter-satellite laser communication terminal according to the embodiment of the present invention;

[0056] Figure 4 It is a system structure diagram of the inter-satellite laser communication based on LCOS according to the embodiment of the present invention. Detailed Embodiments

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0058] The technical solutions of the present invention will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0059] Figure 1 It is a schematic flowchart of the LCOS linearity calibration method based on the CubeSat laser communication terminal according to the embodiment of the present invention, as Figure 1 shown, the method includes:

[0060] Obtain the correspondence between the driving voltage and the actual phase response of the LCOS device in the cube satellite laser communication terminal; generate an initial correction curve of the driving voltage and the actual phase response of the LCOS device according to the correspondence;

[0061] Segment the initial correction curve according to the driving voltage, perform least squares fitting on the phase response within each driving voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves until the slope difference at the boundary points of adjacent segmented fitting curves is less than a preset slope threshold to obtain an optimized segmented fitting curve;

[0062] Use the optimized segmented fitting curve as a reference curve, and establish a mapping relationship table between the target phase value and the driving voltage of the LCOS device by means of two-way search;

[0063] During the operation of the cube satellite laser communication terminal, collect the temperature parameters of the LCOS device in real time, perform temperature compensation correction on the mapping relationship table according to the temperature parameters to obtain a temperature-compensated mapping relationship table, and apply a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relationship table.

[0064] In an alternative embodiment, the method further includes realizing optical path displacement compensation based on the fiber automatic alignment of the LCOS device:

[0065] Display blazed gratings with different directions and periods on the LCOS device to generate multiple diffracted beams, control the multiple diffracted beams to perform traversal scanning along a spiral path, and when any one of the diffracted beams is detected, obtain the relative displacement azimuth angle between the optical fiber and the light spot; [[ID=:18]]

[0066] Determine a sector search area according to the relative displacement azimuth angle, gradually expand the search range within the sector search area for energy detection, use the position of the maximum energy detected in each sector search area as the search starting point for the next sector area, and when the local maximum value of the light intensity is detected, obtain the relative displacement intermediate value between the optical fiber and the light spot;

[0067] Based on the relative displacement azimuth angle and the relative displacement intermediate value, perform a jump search between different diffraction orders to obtain the absolute value of the relative displacement;

[0068] Determine the optical fiber position according to the relative displacement azimuth angle and the absolute value of the relative displacement, and perform local search within the neighborhood of the optical fiber position with a fine step size smaller than the initial step size until the compensation position with the best optical fiber coupling efficiency is obtained;

[0069] According to the compensation position, a corresponding blazed grating pattern is displayed on the LCOS device to achieve optical path displacement compensation.

[0070] Blazed gratings with different directions and periods are displayed on the LCOS device to generate multiple diffracted beams, and these diffracted beams are controlled to perform a traversal scan to achieve the detection and compensation of the relative displacement between the optical fiber and the light spot.

[0071] Blazed gratings with different directions and periods are displayed on the LCOS device to generate multiple diffracted beams. The period of the blazed grating can be set from 8 μm to 12 μm, and the groove depth modulation amount of the blazed grating is from 0.4π to 0.6π to generate at least 4 diffracted beams in different directions. The control system drives these diffracted beams to perform a traversal scan along a spiral path. The step size of the spiral path is 1 / 10 to 1 / 5 of the optical fiber mode field diameter, and the scan range is 10 to 20 times the optical fiber mode field diameter. When any diffracted beam is detected by the photodetector, the system records the current position information to obtain the relative displacement azimuth angle between the optical fiber and the light spot. For example, if a light signal is detected at the coordinates (35 μm, 42 μm) during the spiral scan, the system calculates that the relative displacement azimuth angle is approximately 50.2 degrees.

[0072] According to the obtained relative displacement azimuth angle, the system determines a fan-shaped search area. The angular range of the fan-shaped area is 15 degrees to 30 degrees on both sides of the azimuth angle, that is, a fan-shaped area of 30 degrees to 60 degrees is formed. Within this fan-shaped search area, the system gradually expands the search range with an initial step size (such as 1 / 8 of the optical fiber mode field diameter, about 1 μm) for energy detection. The initial search starting point is the position where the signal is detected, such as (35 μm, 42 μm), and the search direction is the central axis direction of the fan-shaped area. The position of the maximum energy detected each time is used as the search starting point for the next fan-shaped area. For example, if in the first fan-shaped search, the energy value of 0.35 mW is detected at (42 μm, 51 μm), which is higher than the energy of other points, then this point is used as the search starting point for the next fan-shaped search. When a local maximum of the light intensity is detected, for example, when the energy at a certain point reaches 0.48 mW and the energy of the surrounding points is lower than this value, the system records this position as the relative displacement intermediate value between the optical fiber and the light spot.

[0073] Based on the obtained relative displacement azimuth and relative displacement intermediate value, the system performs a jumping search between different diffraction orders to obtain the absolute value of the relative displacement. Specifically, the system calculates the position intervals of different diffraction orders according to the period of the blazed grating. For example, for a grating with a period of 10 μm, the spatial interval between adjacent diffraction orders is approximately 62 μm. The system takes the relative displacement intermediate value as a reference and searches ±3 diffraction orders along the azimuth direction with the diffraction order interval as the step size. For example, if the intermediate value position is (42 μm, 51 μm) and the azimuth angle is 50.2 degrees, the system will search positions such as (-144 μm, -135 μm), (-82 μm, -73 μm), (104 μm, 113 μm), (166 μm, 175 μm), etc. By comparing the energy values at these positions, the position of the maximum energy point is determined. For example, if the energy value at (104 μm, 113 μm) is 0.72 mW, which is higher than all other search points, then this position is the absolute value of the relative displacement.

[0074] According to the determined relative displacement azimuth and absolute value of the relative displacement, the system can determine the precise position of the optical fiber. In the neighborhood of this position, the system performs a local search with a fine step size smaller than the initial step size (such as 0.2 μm to 0.5 μm) to obtain the compensation position for the best optical fiber coupling efficiency. Specifically, the system performs a grid search with a step size of 0.3 μm within a range of ±5 μm centered at (104 μm, 113 μm), and a total of about 289 points are tested. Among these points, if the maximum energy value of 0.86 mW is measured at (105.4 μm, 112.1 μm), then this point is the compensation position for the best optical fiber coupling efficiency.

[0075] After obtaining the compensation position, the system calculates the parameters of the blazed grating pattern to be displayed on the LCOS device according to this position. The modulation depth of the blazed grating is adjusted according to the distance of the compensation position, usually between 0.4π and 0.8π. The period and direction of the blazed grating are also optimized according to the compensation requirements. For example, for the compensation position of (105.4 μm, 112.1 μm), the system calculates that the period of the blazed grating is 9.8 μm, the direction angle is 43.2 degrees, and the modulation depth is 0.65π. The system loads the blazed grating pattern corresponding to these parameters onto the LCOS device, and through the diffraction principle, realizes the precise compensation of the optical path displacement, and finally realigns the optical fiber with the light spot to restore the best coupling efficiency.

[0076] Through the above method, the system can automatically detect the displacement situation and perform precise compensation when the relative displacement occurs between the optical fiber and the light spot, without manual intervention, greatly improving the stability and reliability of the optical system. This method is particularly suitable for fields such as optical communication systems and optical measurement systems that require long-term stable operation.

[0077] The method further includes:

[0078] The first stage of self-calibration is the same as the traditional method of realizing optical path displacement compensation through fast steering mirrors, and spiral traversal scanning is performed. That is, by displaying blazed gratings with different directions and periods on the LCOS, the beam transmission direction is changed, causing the light spot to rotate around the initial position and continuously search outward. The difference from the traditional technology lies in the termination condition of the spiral traversal search process. In the traditional method, the spiral traversal process continues until the beam is deflected to the receiving end. The greater the displacement deviation in the entire optical path, the more serious the offset between the receiving end and the light spot, and the longer the compensation process takes, showing a quadratic growth relationship. Once the offset distance is slightly large, the number of search iteration steps easily reaches tens of thousands, and it is difficult to complete the compensation within one receiving window period. In the present invention, the LCOS is used to replace the FSM as the beam deflection element, which can greatly reduce the spiral traversal search steps. Since the LCOS is a diffractive optical element, it can not only control the beam deflection but also control the beam splitting. Through hologram design, the beam can be divided into multiple beams corresponding to each diffraction order of the grating. The higher the diffraction order, the greater the beam deflection angle. In the spiral traversal search stage of the present invention, the search can end as long as any diffracted light spot is detected. At this time, the azimuth angle Φ of the relative displacement between the optical fiber and the light spot can be determined, but at this time, the higher-order diffraction orders are mixed, and the absolute value R of the relative displacement cannot be confirmed.

[0079] After determining the azimuth angle Φ of the relative displacement between the optical fiber and the light spot, enter the second stage of self-calibration - sector stepping scan. Compared with the spiral traversal, this stage only needs to search within a very small sector area. After each sector area is searched, continue to search outward in a sector shape with the position having the maximum detected energy within this area until a sufficiently sharp light spot is found, that is, when the local maximum value is searched, determine the relative displacement intermediate value r and end the sector stepping scan stage.

[0080] After determining the azimuth angle Φ of the relative displacement between the optical fiber and the light spot and the relative displacement intermediate value r, enter the third stage of self-calibration - diffraction jump scan. This stage uses the geometric relationship between diffraction orders as a priori conditions to perform jump scans between different diffraction orders. That is, fix the azimuth angle Φ, change the relative displacement of the light spot to 2r, and search within its neighborhood; after the search is completed, change the relative displacement of the light spot to 3r and search within its neighborhood again; and so on, change the relative displacement of the light spot to 4r, 5r... until the position of the optical fiber is searched and the absolute value R of the relative displacement is determined.

[0081] After determining the azimuth angle Φ of the relative displacement between the optical fiber and the light spot and the absolute value R of the relative displacement, enter the final fine search stage, and search within its neighborhood with a step size of 1 / 10 to achieve the best optical fiber coupling efficiency compensation effect.

[0082] The fiber optic fast coupling method adopted by the present invention reduces the search steps by hundreds of times compared with the traditional method, and can achieve system self-calibration within ten seconds or even seconds, greatly improving the system operation efficiency and accuracy.

[0083] In an optional embodiment, based on the relative displacement azimuth angle and the relative displacement intermediate value, the jump search between different diffraction orders includes:

[0084] Set multiple search positions by incrementing the relative displacement intermediate value in integer multiples, perform light intensity detection within the neighborhood of each search position, and when the maximum light intensity is detected, obtain the absolute value of the relative displacement between the optical fiber and the light spot.

[0085] After determining the relative displacement azimuth angle and the relative displacement intermediate value, perform a jump search to find the best matching position between different diffraction orders. The core idea of the jump search is to utilize the periodic characteristics of the diffraction orders and quickly locate the best coupling position between the optical fiber and the light spot by performing light intensity detection at preset search positions.

[0086] In specific implementation, the system first sets multiple search positions according to the relative displacement intermediate value. The setting of these search positions follows the principle of incrementing in integer multiples. For example, if the relative displacement intermediate value is 12 micrometers, the search positions that can be set include 12 micrometers, 24 micrometers, 36 micrometers, 48 micrometers, etc. These positions respectively correspond to the coupling points under different diffraction orders.

[0087] The setting of the search positions needs to consider parameters such as the fiber mode field diameter and the light spot divergence angle. In practical applications, assume that a single-mode fiber is used, its mode field diameter is 10 micrometers, and the divergence angle of the light spot at a specific wavelength (such as 1550 nanometers) is 0.1 radian, then the relative displacement intermediate value is 15 micrometers. Accordingly, the search positions can be set as 15 micrometers, 30 micrometers, 45 micrometers, 60 micrometers, etc.

[0088] When performing precise detection at each search position, the system not only measures the light intensity at this position, but also performs scanning detection within its neighborhood range. The size of the neighborhood range is usually set to 10%-20% of the relative displacement intermediate value. Continuing the above example, if the intermediate value is 15 micrometers, the neighborhood range can be set to ±1.5 micrometers to ±3 micrometers. Within this range, the system scans point by point with a step size of 0.1 micrometer and records the light intensity value at each position.

[0089] In the actual implementation process, the light intensity detection is measured using a high-precision optical power meter. For example, when the system scans in the neighborhood of the 30-μm position (i.e., in the range of 27 μm to 33 μm), the following light intensity data are obtained: the light intensity is 0.21 mW at 27.0 μm, 0.25 mW at 27.5 μm, 0.32 mW at 28.0 μm, and it increases successively to reach the maximum value of 0.78 mW at 29.8 μm, then it is 0.75 mW at 30.0 μm, and subsequently gradually decreases to 0.18 mW at 33.0 μm.

[0090] By comparing the maximum light intensity values in the neighborhoods of each search position, the system can determine which diffraction order provides the best coupling effect. If the 0.78 mW detected at 29.8 μm is the maximum value among all search positions, the system determines 29.8 μm as the absolute value of the relative displacement between the optical fiber and the light spot.

[0091] During the light intensity detection process, the relative displacement azimuth angle needs to be kept constant. For example, if the previously determined azimuth angle is 37 degrees, then during the entire jumping search process, the moving direction of the optical fiber relative to the light spot always maintains this angle. This ensures that the search process proceeds along the correct radial direction.

[0092] In practical applications, the system usually sets a light intensity threshold to improve the search efficiency. For example, the threshold can be set to 80% of the theoretical maximum light intensity. When the light intensity detected at a certain position exceeds this threshold, the system considers that the appropriate coupling point has been found and can terminate the search process in advance. For the above example, if the theoretical maximum light intensity is 1.0 mW, the threshold is set to 0.8 mW. Since the actual maximum detected value is 0.78 mW, which is close to but does not exceed the threshold, the system will continue to complete the scanning of all preset positions.

[0093] To cope with the multi-peak situation, the system also records the positions and light intensities of each local maximum point. If there are multiple close light intensity peaks, the system will further perform higher-precision scanning at these positions, such as reducing the step size to 0.01 μm, to determine the true optimal coupling position.

[0094] Another key advantage of the jumping search is that it significantly reduces the search time. The traditional point-by-point scanning method requires 1000 measurements with a small step size (such as 0.1 μm) in the entire range (such as 0 - 100 μm), while the jumping method only needs to perform neighborhood scans at 4 - 5 positions through preset position searches, and the total number of measurements is reduced to about 300 times, with the efficiency increased by more than 3 times.

[0095] In some application scenarios, to further improve the accuracy, after the system determines the absolute value of the relative displacement, a fine-tuning optimization will be performed. Specifically, centered on the determined position, a fine scan is carried out within an extremely small range (such as ±0.5 microns) with a smaller step size (such as 0.01 microns) to obtain the optimal coupling position accurate to the 0.01-micron level. For example, if the initially determined position is 29.8 microns, it is corrected to 29.78 microns after fine-tuning.

[0096] This method has successfully achieved the efficient automatic coupling of the optical fiber and the light spot. The test results show that its positioning accuracy can reach 0.01 microns, the coupling efficiency can exceed 95%, and the time required to complete the entire search process is usually less than 10 seconds, which is much better than the several minutes usually required by traditional manual adjustment methods.

[0097] In an alternative embodiment, the initial correction curve is segmented according to the driving voltage, and the phase response within each driving voltage interval is fitted by the least squares method to obtain a segmented fitting curve. Dynamically adjusting the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves includes:

[0098] Obtain the phase response curve of the LCOS device under the action of the driving voltage, calculate the second derivative of the phase response curve, determine the initial segmentation points according to the extreme points of the second derivative, and divide the phase response curve into multiple initial segmentation intervals;

[0099] For the phase response data in each segmentation interval of the initial segmentation intervals, establish an nth-order polynomial fitting model, and use the least squares method to solve the coefficients of the nth-order polynomial fitting model to obtain the segmented fitting function corresponding to each segmentation interval;

[0100] Calculate the left slope and the right slope of two adjacent segmented fitting functions at the segmentation point, and obtain the difference between the left slope and the right slope, where the left slope is the first derivative value of the segmented fitting function on the left side of the segmentation point, and the right slope is the first derivative value of the segmented fitting function on the right side of the segmentation point;

[0101] When the slope difference at any segmentation point is greater than the preset slope threshold, determine the offset direction of the segmentation point according to the magnitude of the slope difference and the relative magnitude relationship between the left slope and the right slope, and move the segmentation point in the determined offset direction by a preset step size, where the preset step size is proportional to the slope difference;

[0102] Repeat the least squares fitting and slope difference calculation for the segmentation intervals divided by the moved new segmentation points until the slope differences at all segmentation points are less than the preset threshold or the preset number of iterations is reached, to obtain the final segmented fitting function.

[0103] For the phase response correction of the LCOS device, the correction accuracy is improved by the piecewise fitting method. An LCOS device with a working wavelength of 532 nm is used in the experiment. First, the phase response data of the device at different gray levels in the range of 0 - 255 are measured. Using an interference measurement device, the phase values corresponding to different gray levels are recorded to obtain the initial phase response curve. The curve shows that the phase is 0 radians at a gray level of 0 and 6.28 radians at a gray level of 255, but the curve exhibits obvious non - linear characteristics.

[0104] Calculate the second - order derivative of the obtained phase response curve. Using the central difference method, calculate the change rate of the first - order derivative of adjacent data points to obtain the second - order derivative values of all sampling points. By analyzing the second - order derivative curve, it is found that there are extreme points at gray levels of approximately 60, 120, and 190. These points correspond to the positions where the curvature of the phase response curve changes the most and are ideal positions for dividing paragraphs. Therefore, these three points are determined as the initial segmentation points, and the entire response curve is divided into 4 initial segmentation intervals: 0 - 60, 61 - 120, 121 - 190, and 191 - 255.

[0105] Establish a third - order polynomial fitting model for each initial segmentation interval. Taking the first interval 0 - 60 as an example, let the gray level be x and the phase value be y, and establish the model y = a0 + a1x + a2x² + a3x³. Substitute all sampling points in this interval into the model to construct a system of linear equations. Use the least - squares method to solve the system of equations to obtain the coefficients a0 = 0.0023, a1 = 0.0152, a2 = 0.0004, a3 = - 0.0000021. Similarly, solve the polynomial coefficients for the other three segmentation intervals respectively to obtain the complete piecewise fitting function.

[0106] Calculate the slope difference of adjacent piecewise functions at the segmentation points. Taking the segmentation point at a gray level of 60 as an example, calculate the first - order derivative value of the left - hand fitting function (0 - 60 segment) at x = 60 to be 0.0375, and the first - order derivative value of the right - hand fitting function (61 - 120 segment) at x = 60 to be 0.0412, and the slope difference is 0.0037. Similarly, calculate the slope differences at gray levels of 120 and 190 to be 0.0042 and 0.0055 respectively.

[0107] Set the preset slope threshold to 0.002. Since the slope differences at all segmentation points are greater than the threshold, segmentation point adjustment is required. For the segmentation point with a gray value of 60, the slope on the right is greater than the slope on the left, indicating that the function rises faster on the right. Therefore, move the segmentation point to the left. Set the basic step size to 2. Considering that the ratio of the slope difference of 0.0037 to the threshold of 0.002 is approximately 1.85, determine the actual movement step size to be 4 (rounded off after multiplying the basic step size by the ratio). Adjust the segmentation point from 60 to 56, refit the two intervals of 0 - 56 and 57 - 120, and calculate that the slope difference at the new segmentation point is 0.0019, which is less than the threshold, and the adjustment is completed.

[0108] Adjust the segmentation points of gray values 120 and 190 in the same way. The segmentation point of gray value 120 is finally adjusted to 124, and the segmentation point of gray value 190 is adjusted to 186. After adjustment, the slope differences at all segmentation points are less than the preset threshold of 0.002, and the segmented fitting curves are smoother at the joints.

[0109] The finally obtained segmented fitting function covers four intervals: 0 - 56, 57 - 124, 125 - 186, and 187 - 255. Verify the corrected curve by randomly selecting 50 gray value points and calculating the phase linearity errors before and after correction. The maximum phase error before correction is 0.42 radians, and after correction, the maximum phase error drops to 0.05 radians. The average error drops from 0.21 radians to 0.023 radians, and the phase linearity is improved by approximately 89%.

[0110] To verify the correction effect, use the corrected driving voltage - phase mapping relationship to generate 4 different phase patterns on the LCOS, including grating, spiral phase, Fresnel lens, and vortex beam. Collect the diffraction images before and after correction through a camera and find that the clarity and contrast of the corrected images are significantly improved, and the diffraction efficiency is increased by approximately 35%, especially in complex phase patterns.

[0111] Through this segmented fitting method of dynamically adjusting segmentation points, the discontinuous problem that appears at the joints in the traditional fixed segmentation point method is solved, the correction accuracy of the LCOS phase response is improved, the corrected phase response becomes more linear, and thus the performance of the LCOS device in the application of optical field modulation is enhanced.

[0112] In an alternative embodiment, using the optimized segmented fitting curve as the reference curve, a mapping relationship table between the target phase value and the driving voltage of the LCOS device is established by means of two-way search, including:

[0113] Obtain the optimized segmented fitting curve of the LCOS device, and use the segmented fitting curve as the reference curve, where the reference curve represents the corresponding relationship between the driving voltage and the phase response of the LCOS device;

[0114] Divide the target phase modulation range of the LCOS device into M discrete phase points, where M is a positive integer and the intervals between adjacent discrete phase points are equal.

[0115] For each of the discrete phase points, set an initial search interval within the driving voltage range of the reference curve. The upper boundary of the initial search interval is the maximum driving voltage, and the lower boundary is the minimum driving voltage.

[0116] Perform a two-way search using the dichotomy method within the initial search interval, including: calculating the phase value corresponding to the midpoint of the current search interval, comparing the phase value with the target phase point. When the phase value is greater than the target phase point, update the upper boundary of the search interval to the current midpoint. When the phase value is less than the target phase point, update the lower boundary of the search interval to the current midpoint.

[0117] Judge whether the difference between the upper boundary and the lower boundary of the current search interval is less than a preset precision threshold. When it is less than the preset precision threshold, take the midpoint of the current search interval as the driving voltage value corresponding to the discrete phase point.

[0118] Repeat the two-way search process for all discrete phase points, establish a one-to-one correspondence between the discrete phase points and the driving voltages, and generate a phase-voltage mapping table for the LCOS device.

[0119] In practical applications, there is a non-linear relationship between the phase response and the driving voltage of the LCOS device. An accurate mapping relationship needs to be established to achieve precise phase modulation. In this embodiment, first obtain the optimized piecewise fitting curve of the LCOS device as the reference curve. This reference curve is obtained by measuring and piecewise fitting the phase responses of the LCOS device at different driving voltages, and can accurately characterize the corresponding relationship between the driving voltage and the phase response. For example, for a certain model of LCOS device, the phase responses at driving voltages with an interval of 0.1 volts in the range of 0 to 5 volts can be measured to obtain 50 measurement points, and then these measurement points are fitted through a piecewise fitting algorithm to obtain the reference curve.

[0120] Based on this reference curve, divide the target phase modulation range of the LCOS device into M discrete phase points. Here, M is a positive integer, generally taking a value of 256, and the intervals between adjacent discrete phase points are equal. For example, for an LCOS device with a phase modulation range of 0 to 2π, it can be evenly divided into 256 discrete points, and the interval between each point is 2π / 256.

[0121] For each discrete phase point, set an initial search interval within the driving voltage range of the reference curve. Taking the above LCOS device as an example, the upper boundary of the initial search interval is the maximum driving voltage of 5 volts, and the lower boundary is the minimum driving voltage of 0 volts. This ensures that the search interval can cover all driving voltage values.

[0122] Perform a two-way search using the bisection method within the initial search interval. The specific operation is as follows: Calculate the phase value corresponding to the midpoint of the current search interval and compare this phase value with the target phase point. Taking the first discrete phase point 0 as an example, the initial search interval is [0V, 5V], and the midpoint is 2.5V. By looking up the phase value corresponding to 2.5V on the reference curve, assuming it is 1.2π, which is greater than the target phase 0, then update the upper boundary of the search interval to 2.5V, and the new search interval becomes [0V, 2.5V]. Continue the bisection search, calculate the phase value corresponding to the midpoint 1.25V of the new interval, assuming it is 0.6π, which is still greater than the target phase 0, then continue to update the upper boundary, and the search interval becomes [0V, 1.25V]. And so on until the search interval is small enough.

[0123] Judge whether the difference between the upper boundary and the lower boundary of the current search interval is less than the preset precision threshold. The preset precision threshold can be set according to actual requirements, such as 0.01 volts. When the interval width is less than this threshold, take the midpoint of the current search interval as the driving voltage value corresponding to this discrete phase point. Continuing the above example, assuming that after multiple iterations, the search interval is reduced to [0V, 0.02V], the interval width is 0.02 volts, which is less than the preset precision threshold of 0.01 volts, then take the midpoint 0.01 volts as the driving voltage value corresponding to the target phase 0.

[0124] Repeat the above two-way search process for all discrete phase points, establish a one-to-one correspondence between discrete phase points and driving voltages, and generate a phase-voltage mapping table for the LCOS device. For example, for 256 discrete phase points, after the above process, a table containing 256 pairs of mapping relationships can be obtained. Each row of this table contains a phase value and its corresponding driving voltage value, such as: {0, 0.01V}, {2π / 256, 0.32V}, {4π / 256, 0.58V}, and so on until {2π, 4.95V}.

[0125] In practical applications, the mapping table established by this two-way search method has high precision and efficiency. Compared with the traditional linear interpolation method, this method can handle the non-linear response characteristics of the LCOS device more accurately and reduce the phase modulation error. Taking a certain model of LCOS device as an example, when using the traditional linear interpolation method, the average phase error is about 0.1π; while after using the two-way search method of this embodiment, the average phase error is reduced to 0.02π, and the phase modulation accuracy is increased by 5 times.

[0126] This method also has good generality and is applicable to LCOS devices of different models. Only by replacing the reference curve can the phase-voltage mapping table of the new device be quickly established without redesigning the algorithm flow. In addition, the computational complexity of this method is O(M*log(N)), where M is the number of discrete phase points and N is the discretization accuracy of the driving voltage, and the computational efficiency is relatively high, making it suitable for implementation in resource-constrained embedded systems.

[0127] Through the above implementation manners, it can be seen that the bidirectional lookup method provided by the present invention can efficiently and accurately establish the phase-voltage mapping relationship of the LCOS device, improve the phase modulation accuracy, effectively solve the phase modulation error problem caused by the non-linear response characteristics of the LCOS device, and provide technical support for the application of the LCOS device in the fields of optical imaging, optical communication, etc.

[0128] In an optional implementation manner, temperature compensation and correction are performed on the mapping relationship table according to the temperature parameter to obtain a temperature-compensated mapping relationship table, and applying a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relationship table includes:

[0129] Taking the phase response at the reference temperature as a reference, calculating the offset of the phase response under other temperature conditions relative to the phase response at the reference temperature to obtain the phase offset corresponding to each sampling temperature point;

[0130] According to the corresponding relationship between the temperature point and the phase offset, establishing a linear relationship model between the temperature change amount and the phase offset to obtain the temperature-phase compensation coefficient;

[0131] During the operation of the LCOS device, the current operating temperature of the LCOS device is collected in real time through a temperature sensor, and the phase compensation value is calculated according to the temperature difference between the current operating temperature and the reference temperature;

[0132] Modifying the phase-voltage mapping table of the LCOS device according to the phase compensation value includes: subtracting the phase compensation value from the target phase value to obtain a compensated phase value, and looking up the corresponding driving voltage from the phase-voltage mapping table according to the compensated phase value;

[0133] Applying the found driving voltage to the LCOS device to achieve precise phase modulation of the LCOS device under different temperature conditions.

[0134] Obtain the phase-voltage mapping relationship table of the LCOS device at the reference temperature. This mapping relationship table is usually established under specific reference temperature conditions (such as 25 °C), and the table records the phase modulation responses corresponding to different driving voltages. In order to enable the LCOS device to maintain accurate phase modulation performance when operating in different temperature environments, it is necessary to perform temperature compensation and correction on this mapping relationship table.

[0135] During the process of temperature compensation and correction, the system implementing the present invention first needs to obtain the phase response data of the LCOS device under different temperature conditions. For example, the system can measure the phase responses of the LCOS device at different driving voltages at multiple temperature points such as 5 °C, 15 °C, 25 °C, 35 °C, 45 °C, etc. in a temperature-controlled environment. The measurement can be carried out through optical devices such as interferometers, and record the phase modulation values corresponding to the driving voltages with a step of 0.1 V in the range of 0 - 5 V at each temperature point.

[0136] After obtaining the phase response data at each temperature point, the system uses the phase response at the reference temperature (such as 25 °C) as a reference standard, and calculates the offset of the phase response under other temperature conditions relative to the phase response at the reference temperature. For example, when the driving voltage of the LCOS device is 3.0 V, the phase modulation value generated at 25 °C is 180 degrees, while the phase modulation value generated at 35 °C is 192 degrees. Then the phase offset relative to the reference temperature at 35 °C is 12 degrees. In this way, the system can obtain a dataset of phase offset corresponding to each sampled temperature point.

[0137] Based on the correspondence between the obtained temperature points and phase offsets, the system establishes a linear relationship model between the temperature change and the phase offset. In actual implementation, the system can perform linear regression analysis on the temperature-phase offset data under each driving voltage to obtain the temperature-phase compensation coefficient. For example, through analysis, it is obtained that when the driving voltage is 3.0 V, for every 1 °C increase in temperature, the phase modulation value will increase by 1.2 degrees. This linear relationship can be expressed as a product relationship between the phase offset and the temperature change, where the multiplier is the temperature-phase compensation coefficient. This coefficient varies with different driving voltages, so the system needs to establish a corresponding temperature-phase compensation coefficient table for different driving voltage ranges.

[0138] During the actual operation of the LCOS device, the system real-time collects the current operating temperature through a temperature sensor integrated on or around the LCOS device. For example, the temperature sensor collects temperature data every 500 milliseconds with a resolution of 0.1 °C. After obtaining the current operating temperature, the system calculates the temperature difference between the current temperature and the reference temperature. Assuming the current temperature is 32 °C and the reference temperature is 25 °C, then the temperature difference is 7 °C.

[0139] Based on the obtained temperature difference and the established temperature-phase compensation coefficient, calculate the phase compensation value under the current temperature condition. The calculation method is: multiply the temperature difference by the temperature-phase compensation coefficient under the corresponding driving voltage. For example, if the temperature-phase compensation coefficient at a driving voltage of 3.0V is 1.2 degrees / °C and the temperature difference is 7°C, then the phase compensation value is 8.4 degrees.

[0140] After obtaining the phase compensation value, correct the phase-voltage mapping table of the LCOS device. The correction method is: when a certain target phase value needs to be achieved, the system first subtracts the calculated phase compensation value from the target phase value to obtain the compensated phase value. For example, if the target phase value is 180 degrees and the phase compensation value is 8.4 degrees, then the compensated phase value is 171.6 degrees. Subsequently, the system looks up the corresponding driving voltage from the original phase-voltage mapping table according to this compensated phase value. Assume that at the reference temperature, the driving voltage corresponding to the phase value of 171.6 degrees is 2.85V.

[0141] The system applies the found driving voltage (such as 2.85V) to the LCOS device, thereby achieving precise phase modulation under the current temperature condition (32°C). Since the phase modulation value increases under the same driving voltage as the temperature rises, this effect is compensated by reducing the driving voltage, ultimately ensuring that the actual phase value output by the LCOS device is consistent with the target phase value (180 degrees).

[0142] In practical applications, to improve the system response speed, the driving voltages corresponding to each target phase value under different temperature conditions can be pre-calculated to form a compensation lookup table. For example, a three-dimensional lookup table with a 5°C temperature interval and a 5-degree phase interval can be established, containing data in three dimensions: temperature, target phase value, and corresponding driving voltage. When the system runs, it only needs to quickly obtain the corresponding driving voltage value from the lookup table according to the current temperature and target phase value through methods such as bilinear interpolation.

[0143] Through the above temperature compensation and correction method, the LCOS device can maintain a phase modulation accuracy within ±3 degrees in the temperature range of -10°C to 60°C, effectively solving the problem of phase modulation drift caused by temperature changes, and improving the application stability and reliability of the LCOS device in various optical systems.

[0144] As Figures 2 - 4 shown, the method further includes:

[0145] The specific implementation plan is as follows:

[0146] [1] Optical head: Customize an optical head with high sensitivity and wavelength adaptability. The processing parties are such as Changchun Institute of Optics and Fine Mechanics and Xi'an Institute of Optics and Precision Mechanics. This optical head can effectively receive laser signals and ensure stable performance within different wavelength ranges.

[0147] [2] Fast Steering Mirror (FSM): A fast steering mirror from Puai Nano Co., Ltd., model S-335, is used. This device enables high-speed and high-precision control of the beam direction to compensate for the mechanical resonance of the system.

[0148] [3] Dichroic Beam Splitter: A dichroic beam splitter from Thorlabs Inc., model DMLP1500L, is used. This dichroic beam splitter is used to separate the input and output laser signals with different wavelengths to enable full-duplex communication (since signal transmission is not involved in this invention, it is not elaborated here).

[0149] [4] Fold Mirror: A high-reflectivity mirror from Edmund Optics, model #47-114, is selected. This fold mirror is used to reflect the laser signal and fold the optical path.

[0150] [5] Narrowband Color Filter: A narrowband color filter provided by Edmund Optics, model #65-779, is used. This filter is used to select optical signals within a specific wavelength range to ensure that the system only receives signals of the target wavelength.

[0151] [6] Beam Splitter: A beam splitter from Thorlabs Inc., model BS039, is selected. This beam splitter is used to split the optical signal into two beams, one of which is used for focusing by the coupling lens, and a small part is used for the tracking camera module.

[0152] [7] Liquid Crystal on Silicon (LCOS) Spatial Light Modulator: An LCOS device from Hamamatsu Corporation, model X15213, is selected. As an alternative to the Fast Steering Mirror (FSM), the LCOS can achieve precise control of the beam by displaying different phase holograms, improving the self-calibration efficiency.

[0153] [8] Coupling Lens: A high-precision coupling lens is customized, and the processing party is such as Jingcui Optics. This lens is used to focus the beam and improve the coupling efficiency of the optical fiber.

[0154] [9] Signal Processor: A self-developed coherent optical QPSK coded optical communication system is used to achieve signal modulation and demodulation (since the signal processing part is not involved in this invention, it is not elaborated here).

[0155]

[10] Tracking Camera Module: A spot analyzer from Cinogy, model CinCam CMOS-1201EL, is selected. This module is used to monitor the spot position in real time and adjust the LCOS through the control circuit to ensure that the system can always receive optical signals with the maximum efficiency.

[0156] In the second aspect of the embodiment of the present invention, a LCOS linearity correction system based on a cube satellite laser communication terminal is provided, including:

[0157] A first unit is configured to obtain the correspondence between the driving voltage and the actual phase response of the LCOS device in the cube satellite laser communication terminal; generate an initial correction curve of the driving voltage and the actual phase response of the LCOS device according to the correspondence;

[0158] A second unit is configured to segment the initial correction curve according to the driving voltage, perform least squares fitting on the phase response within each driving voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves until the slope difference at the boundary points of adjacent segmented fitting curves is less than a preset slope threshold, so as to obtain an optimized segmented fitting curve;

[0159] A third unit is configured to use the optimized segmented fitting curve as a reference curve and establish a mapping relationship table between the target phase value and the driving voltage of the LCOS device by means of bidirectional search;

[0160] A fourth unit is configured to, during the operation of the cube satellite laser communication terminal, collect the temperature parameters of the LCOS device in real time, perform temperature compensation correction on the mapping relationship table according to the temperature parameters to obtain a temperature-compensated mapping relationship table, and apply a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relationship table.

[0161] In a third aspect of the embodiments of the present invention,

[0162] An electronic device is provided, including:

[0163] A processor;

[0164] A memory for storing instructions executable by the processor;

[0165] Wherein, the processor is configured to call the instructions stored in the memory to execute the method described above.

[0166] In a fourth aspect of the embodiments of the present invention,

[0167] A computer-readable storage medium is provided, on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the method described above is implemented.

[0168] The present invention may be a method, an apparatus, a system, and / or a computer program product. The computer program product may include a computer-readable storage medium, on which computer-readable program instructions for executing various aspects of the present invention are uploaded.

[0169] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for LCOS linearity correction based on a cube satellite laser communication terminal, characterized in that Including: Obtain the correspondence between the driving voltage and the actual phase response of the LCOS device in the cube satellite laser communication terminal; Generate an initial correction curve of the driving voltage and the actual phase response of the LCOS device according to the correspondence; Segment the initial correction curve according to the driving voltage, perform least squares fitting on the phase response within each driving voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves until the slope difference at the boundary points of adjacent segmented fitting curves is less than a preset slope threshold to obtain an optimized segmented fitting curve; Use the optimized segmented fitting curve as a reference curve and establish a mapping relationship table between the target phase value and the driving voltage of the LCOS device by means of two-way search; During the operation of the cube satellite laser communication terminal, collect the temperature parameters of the LCOS device in real time, perform temperature compensation correction on the mapping relationship table according to the temperature parameters to obtain a temperature-compensated mapping relationship table, and apply a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relationship table.

2. The method according to claim 1, characterized in that The method further includes realizing optical path displacement compensation based on the automatic alignment of the optical fiber of the LCOS device: Display blazed gratings with different directions and periods on the LCOS device to generate multiple diffracted beams, control the multiple diffracted beams to perform traversal scanning along a spiral path, and when any one of the diffracted beams is detected, obtain the relative displacement azimuth angle between the optical fiber and the light spot; Determine a sector search area according to the relative displacement azimuth angle, gradually expand the search range within the sector search area for energy detection, use the position of the maximum energy detected in each sector search area as the search starting point for the next sector area, and when the local maximum value of the light intensity is detected, obtain the relative displacement intermediate value between the optical fiber and the light spot; Based on the relative displacement azimuth angle and the relative displacement intermediate value, perform a jump search between different diffraction orders to obtain the absolute value of the relative displacement; Determine the optical fiber position according to the relative displacement azimuth angle and the absolute value of the relative displacement, and perform local search within the neighborhood of the optical fiber position with a fine step size smaller than the initial step size until the compensation position with the best optical fiber coupling efficiency is obtained; Display the corresponding blazed grating pattern on the LCOS device according to the compensation position to realize optical path displacement compensation.

3. The method according to claim 2, wherein Performing a jump search between different diffraction orders based on the relative displacement azimuth angle and the relative displacement intermediate value includes: Set multiple search positions by incrementing the relative displacement intermediate value in integer multiples, perform light intensity detection within the neighborhood of each search position, and when the maximum light intensity is detected, obtain the absolute value of the relative displacement between the optical fiber and the light spot.

4. The method according to claim 1, wherein Segment the initial correction curve according to the driving voltage, perform least squares fitting on the phase response within each driving voltage interval to obtain a segmented fitting curve, and dynamically adjust the segmentation points based on the slope difference of the boundary points of adjacent segmented fitting curves includes: Obtain the phase response curve of the LCOS device under the action of the driving voltage, calculate the second derivative of the phase response curve, determine the initial segmentation points according to the extreme points of the second derivative, and divide the phase response curve into multiple initial segmentation intervals; For the phase response data in each segmentation interval of the initial segmentation intervals, establish an nth-order polynomial fitting model, and use the least squares method to solve the coefficients of the nth-order polynomial fitting model to obtain the segmentation fitting function corresponding to each segmentation interval; Calculate the left slope and the right slope of two adjacent segmentation fitting functions at the segmentation point, and obtain the difference between the left slope and the right slope, where the left slope is the first derivative value of the segmentation fitting function on the left side of the segmentation point, and the right slope is the first derivative value of the segmentation fitting function on the right side of the segmentation point; When the slope difference at any segmentation point is greater than the preset slope threshold, determine the offset direction of the segmentation point according to the magnitude of the slope difference and the relative magnitude relationship between the left slope and the right slope, and move the segmentation point by a preset step length in the determined offset direction, where the preset step length is proportional to the slope difference; Repeat the least squares fitting and slope difference calculation for the segmentation intervals divided by the moved new segmentation points until the slope differences at all segmentation points are less than the preset threshold or the preset number of iterations is reached, and obtain the final segmentation fitting function.

5. The method according to claim 1, wherein Take the optimized segmented fitting curve as the reference curve, and establish a mapping relationship table between the target phase value and the driving voltage of the LCOS device by using a two-way search method, including: Obtain the optimized segmented fitting curve of the LCOS device, and take the segmented fitting curve as the reference curve, where the reference curve represents the corresponding relationship between the driving voltage and the phase response of the LCOS device; Divide the target phase modulation range of the LCOS device into M discrete phase points, where M is a positive integer and the intervals between adjacent discrete phase points are equal; For each of the discrete phase points, set an initial search interval within the driving voltage range of the reference curve, where the upper boundary of the initial search interval is the maximum driving voltage and the lower boundary is the minimum driving voltage; Perform two-way search within the initial search interval by using the bisection method, including: calculating the phase value corresponding to the midpoint of the current search interval, comparing the phase value with the target phase point, when the phase value is greater than the target phase point, updating the upper boundary of the search interval to the current midpoint, and when the phase value is less than the target phase point, updating the lower boundary of the search interval to the current midpoint; Judge whether the difference between the upper boundary and the lower boundary of the current search interval is less than the preset precision threshold. When it is less than the preset precision threshold, take the midpoint of the current search interval as the driving voltage value corresponding to the discrete phase point; Repeat the two-way search process for all discrete phase points to establish a one-to-one correspondence between the discrete phase points and the driving voltages, and generate a phase-voltage mapping table of the LCOS device.

6. The method according to claim 1, characterized in that Performing temperature compensation and correction on the mapping relation table according to the temperature parameter to obtain a temperature-compensated mapping relation table, and applying a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relation table includes: Taking the phase response at the reference temperature as a reference, calculating the offset of the phase response under other temperature conditions relative to the phase response at the reference temperature, and obtaining the phase offset corresponding to each sampling temperature point; Establishing a linear relationship model between the temperature change and the phase offset according to the corresponding relationship between the temperature point and the phase offset, and obtaining the temperature-phase compensation coefficient; During the operation of the LCOS device, the current operating temperature of the LCOS device is collected in real time through a temperature sensor, and the phase compensation value is calculated according to the temperature difference between the current operating temperature and the reference temperature; Correcting the phase-voltage mapping table of the LCOS device according to the phase compensation value, including: subtracting the phase compensation value from the target phase value to obtain the compensated phase value, and looking up the corresponding driving voltage from the phase-voltage mapping table according to the compensated phase value; Applying the found driving voltage to the LCOS device to achieve precise phase modulation of the LCOS device under different temperature conditions.

7. An LCOS linearity correction system for a cube satellite laser communication terminal, which is used to implement the method according to any one of claims 1-6, and is characterized in that, Including: A first unit for obtaining the correspondence between the driving voltage and the actual phase response of the LCOS device in the cubic satellite laser communication terminal; Generating an initial correction curve of the driving voltage and the actual phase response of the LCOS device according to the correspondence; A second unit for segmenting the initial correction curve according to the driving voltage, performing least squares fitting on the phase response in each driving voltage interval to obtain a segmented fitting curve, and dynamically adjusting the segmentation points based on the slope difference of the boundary points of the adjacent segmented fitting curves until the slope difference at the boundary points of the adjacent segmented fitting curves is less than a preset slope threshold, and obtaining an optimized segmented fitting curve; A third unit for using the optimized segmented fitting curve as a reference curve and establishing a mapping relation table between the target phase value and the driving voltage of the LCOS device by means of two-way lookup; A fourth unit for, during the operation of the cubic satellite laser communication terminal, collecting the temperature parameter of the LCOS device in real time, performing temperature compensation and correction on the mapping relation table according to the temperature parameter to obtain a temperature-compensated mapping relation table, and applying a corresponding driving voltage to the LCOS device according to the temperature-compensated mapping relation table.

8. An electronic device, characterized in that, Including: A processor; A memory for storing instructions executable by the processor; Wherein, the processor is configured to call the instructions stored in the memory to execute the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, the method according to any one of claims 1 to 6 is implemented.

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