Two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization

Abstract

This invention relates to a two-dimensional spatial laser communication beam coupling method based on sharpness-perception minimization, belonging to the field of spatial laser communication technology, and solving the technical problem that existing algorithms for improving coupling effects often fail to achieve the expected coupling results. The method includes the following steps: acquiring optical power in the neighborhood of the current spot position; performing gradient estimation based on the acquisition results; calculating the next position of the spot based on the sharpness-perception minimization algorithm; acquiring the optical power output at the adjusted spot position; if the optical power output meets the requirements, pausing coupling and continuously monitoring the optical power; otherwise, returning to the initial steps. The two-dimensional spatial laser communication beam coupling method based on sharpness-perception minimization of this invention provides more accurate gradient estimation, with a higher degree of agreement between the estimated gradient and the actual gradient; it can escape local optima and improve the ability to find the global optimum.

Description

Technical Field

[0001] This invention relates to the field of space laser communication technology, and in particular to a two-dimensional space laser communication beam coupling method based on sharpness perception minimization. Background Technology

[0002] Laser communication, due to its advantages such as high communication speed and good security, is currently widely used in various communication applications, including inter-satellite and satellite-to-ground communication. However, to achieve long-distance laser communication between two parties, the primary task is to establish a reliable communication link. The laser emitted by the transmitting end device passes through the atmospheric channel and the receiving lens group, forming a light spot on the fiber end face of the laser communication receiving terminal. The degree of coupling between this light spot and the fiber core determines the received optical power, thus affecting the communication speed. However, interference from factors such as atmospheric turbulence, platform vibration, and human assembly errors can cause alignment deviations between the light spot and the fiber core, resulting in low coupling efficiency, low received signal power, and low signal-to-noise ratio, thus affecting the communication effect.

[0003] To address the aforementioned issues, a suitable fiber coupling algorithm is needed to improve the coupling efficiency of the receiving fiber. The output optical power varies depending on the position of the light spot on the fiber endface. This variation is closely related to device setup, the environment, and the atmospheric channel, factors that cannot be accurately obtained in advance. Therefore, to obtain ideal optical power output, the position of the light spot typically needs to be adjusted in real-time during the communication phase, and the direction in which the light spot should continue to move should be determined based on feedback. The input to this process is the position of the light spot (which can be changed by controlling the angle of the fast reflector), and the output is the optical power (which can be acquired using a signal power meter). If we disregard the specific system and only consider the input and output, this process is very similar to a nonlinear optimization problem. Therefore, current mainstream methods are designed based on this problem form to improve coupling efficiency.

[0004] Currently, there are two main types of algorithms that can improve coupling performance: nutation and stochastic parallel gradient descent (SPGD). Both algorithms work by adjusting the angle of the fast reflector in the receiving lens group to change the position of the light spot on the fiber end face, thereby gradually coupling the light spot into the fiber core.

[0005] In the nutation algorithm, the lateral position of the light spot is adjusted by changing the angle of the fast-reflecting mirror. When adjusting the lateral position, the light spot moves around the initial iteration point as the center, at a certain length... Move along a circle with a radius (nutation radius) to collect data. The optical power output at each point is then sorted, and the point with the highest output optical power is identified. After that, direct the light spot towards The direction of movement is shifted by the length d (nutation step size). Then, the above steps are repeated until the output optical power dynamically stabilizes within an acceptable range, and the search continues iteratively based on real-time changes in optical power. The SPGD algorithm, as its name suggests, is a gradient descent-based method. It applies two sets of perturbations of equal magnitude and opposite directions in the horizontal direction (x and y), and then determines the direction of the next iteration based on the power returned by each perturbation.

[0006] Current nutation and stochastic parallel gradient descent algorithms both search for the position that maximizes optical power output through iterative steps. However, due to their relatively fixed parameter settings and lack of necessary escaping mechanisms, both algorithms are prone to finding a local optimum of optical power when the channel conditions are complex, leading to unsatisfactory coupling effects. Summary of the Invention

[0007] This invention aims to address the technical problems in existing algorithms for improving coupling effects, such as fixed parameter settings, lack of exit mechanisms, and difficulty in achieving the expected coupling effect. It provides a two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0009] A two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization includes the following steps:

[0010] Step 1: Collect optical power in the neighborhood of the current location of the light spot;

[0011] Control the fast reflector to move the position of the light spot and collect the optical power output at the corresponding position;

[0012] Step 2: Perform gradient estimation based on the collected results;

[0013] Based on the optical power collected in step 1, the trend of optical power change at the current location of the light spot is estimated by weighted averaging.

[0014] Step 3: Calculate the next position of the light spot based on the sharpness-perceived minimization algorithm;

[0015] Based on the optical power change trend estimated in step 2, the control quantity is calculated using the sharpness perception minimization algorithm to adjust the position of the light spot;

[0016] Step 4: Acquire the optical power output at the adjusted spot position;

[0017] After moving the light spot based on the results of step 3, the optical power output at the moved position is collected.

[0018] Step 5: If the optical power output meets the requirements, pause coupling and maintain continuous monitoring of the optical power; otherwise, return to step 1. Specifically:

[0019] If the difference between the optical power output in step 4 and the expected optical power is less than the threshold, stop adjusting the spot position and continue monitoring the optical power; otherwise, return to step 1 and repeat the above steps.

[0020] In the above technical solution, the coordinates of the sampling point in the optical power output at the corresponding location collected in step 1 are calculated as follows: based on the current position of the light spot. Collection radius Number of sampling points The coordinates of each sampling point are calculated as follows:

[0021]

[0022] in, For the data collection location, This is the location number for data collection. The x-coordinate of the current position of the light spot. The vertical coordinate of the current position of the light spot is . The range of values ​​is , This is the sampling point number.

[0023] In the above technical solution, step 2 specifically includes:

[0024] The optical power acquired in step 1 and corresponding collection location Written as ,in ; and These represent the data collection locations. The horizontal and vertical coordinates;

[0025] Current position of light spot The trend of optical power variation is as follows:

[0026]

[0027] in, For gradient.

[0028] In the above technical solution, step 3 specifically includes:

[0029] Step 31: Calculate the disturbance amount and location;

[0030] Disturbance The calculation is as follows:

[0031]

[0032] in, For perturbation neighborhood scale;

[0033] Disturbance location The calculation is as follows:

[0034]

[0035] Step 32: Estimate the gradient at the location of the perturbation. ;

[0036] Gradient at the perturbation location The estimate is:

[0037]

[0038] Step 33: Parameter update;

[0039] Next position of the light spot for:

[0040]

[0041] in, Step size factor Weight decay;

[0042] Step 34: Adjust the position of the light spot;

[0043] Move the light spot to the next position This is converted into a fast reflector control value, and the position of the light spot is adjusted according to this fast reflector control value.

[0044] The present invention has the following beneficial effects:

[0045] The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention provides more accurate gradient estimation: The present invention uses a weighted average method for gradient estimation. Compared with the classical method that only uses the direction with the maximum optical power output as the gradient estimation, the method of the present invention can integrate all optical power acquisition results, and the estimated gradient matches the real gradient to a higher degree.

[0046] The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention can escape local optima: The present invention uses a sharpness perception minimization algorithm to calculate the position of the next spot. It not only focuses on the optical power of the neighborhood of the current position, but also jumps out of the local area to observe the optical power changes in the surrounding area. This mechanism provides the ability to escape local optima and improves the ability to find the global optimal region. Attached Figure Description

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0048] Figure 1 This is a schematic diagram of the system to which the two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention is applicable.

[0049] Figure 2 This is a schematic diagram of the software architecture and environment in a system to which the two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention is applicable.

[0050] Figure 3 This is a schematic diagram illustrating the workflow of the two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization according to the present invention. Detailed Implementation

[0051] The inventive concept of this invention is as follows:

[0052] The present invention provides a two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization. This method uses numerical optimization to correct the lateral deviation between the light spot and the fiber core, thereby improving the coupling degree between the light spot and the fiber core, which enhances the received optical signal power and improves the signal-to-noise ratio.

[0053] The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention can actively explore the power situation of a wider surrounding area, has the ability to escape local optima, and has a higher coupling success rate in complex channel environments.

[0054] The present invention will now be described in detail with reference to the accompanying drawings.

[0055] The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention is applicable to systems such as... Figure 1As shown, the system includes, in sequence along the optical path, a coupling lens, a single-mode fiber, an optical power meter, a main control unit, and a fast reflector. The coupling lens effectively couples the incident laser beam into the single-mode fiber; the single-mode fiber transmits the laser beam; the optical power meter measures and outputs the optical signal power; the main control unit coordinates the input, processing, and output operations through signal commands, and issues control commands in pulse or potential form according to logical operation requirements to control the output; the fast reflector controls the beam direction between the light source and the receiver.

[0056] The main control unit runs control software, and the control software architecture (component modules) and environment are as follows: Figure 2 As shown, it consists of hardware and software.

[0057] The following is combined with Figure 1-3 Specifically, the two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention can be summarized into 5 steps, and the workflow is as follows: Figure 3 As shown ( Figure 3 (Only a summary of the steps is shown in the text), and the specific description is as follows:

[0058] Step 1: Collect optical power in the neighborhood of the current location of the light spot;

[0059] Control the fast reflector to move the position of the light spot and collect the optical power output at the corresponding position;

[0060] The method of this invention applies to a system whose front-end receiving device detects the incident laser input, at which point the system enters a beam coupling state. At the current position of the laser spot... The gradient estimation algorithm module outputs control quantities to control the deflection of the fast reflector, fine-tune the position of the light spot, and reads the optical power at the corresponding position from the optical power meter through the optical power acquisition module.

[0061] Step 2: Perform gradient estimation based on the acquisition results (optical power output);

[0062] Based on the optical power collected in step 1, the trend of optical power change at the current location of the light spot is estimated by weighted averaging.

[0063] The gradient estimation algorithm module in the main control unit is used to process the collected optical power, and a weighted average method is used to estimate the trend of optical power change at the current position of the light spot. The changes in optical power within the neighborhood are analyzed, and the gradient is estimated accordingly.

[0064] Step 3: Calculate the next position of the light spot based on the Sharpness-Perceived Minimization (SAM) algorithm. ;

[0065] Based on the optical power change trend estimated in step 2, a control variable is calculated using a sharpness-perceived minimization algorithm to adjust the spot position; specifically:

[0066] The optical power change trend, i.e., the gradient estimation result, from step 2 is passed to the coupled algorithm module. In this module, the Sharpness Aware Minimization (SAM) algorithm is used to calculate where the light spot should move, i.e., to calculate... .at this time, Figure 3 In The value of m is 0. Right now .

[0067] Step 4: Acquire the optical power output at the adjusted spot position;

[0068] After moving the light spot based on the results of step 3, the optical power output at the moved position is collected.

[0069] After the calculation is complete, the corresponding control input is sent to the fast reflector to adjust the position of the light spot. Once adjusted, the image is acquired. Optical power at the location .at this time, Figure 3 In middle The value is 0. Right now .

[0070] Step 5: If the optical power output meets the requirements, pause coupling and maintain continuous monitoring of the optical power; otherwise, return to step 1. Specifically:

[0071] If the difference between the optical power output in step 4 and the expected optical power is less than the threshold, then stop adjusting the spot position; otherwise, return to step 1 and repeat the above steps.

[0072] If the optical power is greater than the threshold, the adjustment of the fast reflector is paused, but the monitoring of the optical power output continues. If the optical power output is dynamically stable within the range above the threshold, the state is maintained; otherwise, the above process is repeated until the condition is met.

[0073] The steps of the method of the present invention will now be described in more detail:

[0074] In step 1 of this invention, a method similar to the traditional nutation method is used to collect the optical power output of a series of points in the neighborhood of the current position of the light spot. The corresponding collection results are provided to the gradient estimation algorithm module for use and processing. Specifically, in the gradient estimation algorithm module, based on the current position of the light spot... Collection radius Number of sampling points Each sampling point The coordinates can be calculated as follows:

[0075]

[0076] in, For the data collection location, This is the location number for data collection. The x-coordinate of the current position of the light spot. The vertical coordinate of the current position of the light spot is . The range of values ​​is , Number the sampling points;

[0077] After calculation, based on the relationship between the coordinates and the control input of the fast reflector, the coordinate values ​​are converted into control voltages and then transmitted to the fast reflector controller in the main control unit. The fast reflector controller executes the control inputs, and after deflection is completed, the software optical power acquisition module reads the optical power at this time from the optical power meter and transmits it to the gradient estimation algorithm module. The gradient estimation algorithm module then acquires the position... and optical power Composition of data pairs Store temporarily for use in subsequent steps.

[0078] In step 2 of this invention, a weighted average method is used to estimate the current position of the light spot. The trend of optical power variation in the neighborhood, i.e., the gradient Specifically, the collected optical power and corresponding collection location Written as ,in This is the location for collecting optical power. and These represent the data collection locations. The horizontal and vertical coordinates. Based on the above definition, the current position of the light spot... The trend of optical power variation is as follows:

[0079] That is, gradient The following can be estimated:

[0080]

[0081] in, For gradient.

[0082] In step 3 of this invention, the Sharpness-Perceived Minimization (SAM) algorithm is used to calculate where the light spot should move next. This step can be specifically divided into 4 sub-steps:

[0083] Step 31: Calculate the disturbance amount and location.

[0084] According to the SAM algorithm process, the perturbation amount It can be calculated in the following way:

[0085]

[0086] in, To perturb the neighborhood scale.

[0087] The disturbance amount was calculated. Next, the location of the disturbance It can be calculated as follows:

[0088]

[0089] Step 32: Estimate the gradient at the location of the perturbation. .

[0090] After obtaining the location of the disturbance Then, following the steps in steps 1 and 2, estimate the gradient at the perturbation location. :

[0091]

[0092] Step 33: Parameter update.

[0093] After obtaining the gradient at the perturbation location Next, the next position of the light spot. for:

[0094]

[0095] in, Step size factor This is weight decay.

[0096] Step 34: Adjust the position of the light spot.

[0097] Move the light spot to the next position The signal is converted into a fast reflector control signal, which is then output to the fast reflector controller in the main control unit to adjust the position of the light spot.

[0098] In step 4 of this invention, the next moving position of the light spot is acquired by the optical power acquisition module. The optical power at that point, let the output of that optical power be The collected results are then output to the coupling algorithm module in the main control unit.

[0099] In step 5 of this invention, the coupling algorithm module will... With the desired optical power output (i.e., threshold) ) compare, if Greater than the threshold If the light spot position modulation fails, continue monitoring of the light spot position and optical power; otherwise, return to step 1 and repeat the above process. If during monitoring... Below the threshold Then, return to step 1 and couple again.

[0100] The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention provides more accurate gradient estimation: The present invention uses a weighted average method for gradient estimation. Compared with the classical method that only uses the direction with the maximum optical power output as the gradient estimation, the method of the present invention can integrate all optical power acquisition results, and the estimated gradient matches the real gradient to a higher degree.

[0101] The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization of the present invention can escape local optima: The present invention uses a sharpness perception minimization algorithm to calculate the position of the next spot. It not only focuses on the optical power of the neighborhood of the current position, but also jumps out of the local area to observe the optical power changes in the surrounding area. This mechanism provides the ability to escape local optima and improves the ability to find the global optimal region.

[0102] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization, characterized in that, Includes the following steps: Step 1: Collect optical power in the neighborhood of the current location of the light spot; Control the fast reflector to move the position of the light spot and collect the optical power output at the corresponding position; Step 2: Perform gradient estimation based on the collected results; Based on the optical power collected in step 1, the trend of optical power change at the current location of the light spot is estimated by weighted averaging. Step 3: Calculate the next position of the light spot based on the sharpness-perceived minimization algorithm; Based on the optical power change trend estimated in step 2, the control quantity is calculated using the sharpness perception minimization algorithm to adjust the position of the light spot; Step 4: Acquire the optical power output at the adjusted spot position; After moving the light spot based on the results of step 3, the optical power output at the moved position is collected. Step 5: If the optical power output meets the requirements, pause coupling and maintain continuous monitoring of the optical power; otherwise, return to step 1. Specifically: If the difference between the optical power output in step 4 and the expected optical power is less than the threshold, stop adjusting the spot position and continue monitoring the optical power; otherwise, return to step 1 and repeat the above steps.

2. The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization according to claim 1, characterized in that, The coordinates of the sampling points in the optical power output at the corresponding location in step 1 are calculated as follows: Based on the current position of the light spot Collection radius Number of sampling points The coordinates of each sampling point are calculated as follows: in, For the data collection location, This is the location number for data collection. The x-coordinate of the current position of the light spot. The vertical coordinate of the current position of the light spot is . The range of values ​​is , This is the sampling point number.

3. The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization according to claim 2, characterized in that, Step 2 is as follows: The optical power acquired in step 1 and corresponding collection location Written as ,in ; and These represent the data collection locations. The horizontal and vertical coordinates; Current position of light spot The trend of optical power variation is as follows: in, For gradient.

4. The two-dimensional spatial laser communication beam coupling method based on sharpness perception minimization according to claim 3, characterized in that, Step 3 specifically includes: Step 31: Calculate the disturbance amount and location; Disturbance The calculation is as follows: in, For perturbation neighborhood scale; Disturbance location The calculation is as follows: Step 32: Estimate the gradient at the location of the perturbation. ; Gradient at the perturbation location The estimate is: Step 33: Parameter update; Next position of the light spot for: in, Step size factor Weight decay; Step 34: Adjust the position of the light spot; Move the light spot to the next position This is converted into a fast reflector control value, and the position of the light spot is adjusted according to this fast reflector control value.

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