Method for realizing high-precision detection of phase error of waveguide phase array by using spatial light modulator
By combining spatial light modulators and intelligent optimization algorithms, high-precision detection and global optimal compensation of waveguide phase array phase errors are achieved, solving the problems of insufficient detection accuracy and complex structure in existing technologies, and improving spectral resolution and energy concentration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-09
- Publication Date
- 2026-03-24
AI Technical Summary
The existing waveguide phase array has insufficient phase error detection accuracy, making it difficult to achieve global optimal compensation. Furthermore, the existing methods are complex or costly, making them unsuitable for multi-channel waveguide phase arrays.
A phase modulation and detection system is constructed using a spatial light modulator. The phase error distribution is inverted by interferometric or superimposed light spot patterns, and phase compensation is performed by combining intelligent optimization algorithms to achieve high-precision detection and global optimal compensation.
It achieves high-precision phase error detection without modifying the waveguide phase array structure, improves optical field coherence and spectral contrast, is suitable for multi-channel arrays, simplifies the structure, and improves spectral resolution and energy concentration.
Smart Images
Figure CN121720596A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of astronomical photonics technology, specifically to a high-precision detection method for waveguide phase array phase errors using a spatial light modulator (SLM). This method is applicable to high-precision detection of phase errors in arrayed waveguide grating (AWG) spectral chips, integrated photonic waveguide arrays, or other multi-channel waveguide phase arrays. It is particularly suitable for performance optimization of waveguide phase arrays such as arrayed waveguide gratings (AWGs), and is especially suitable for high-resolution astronomical spectrometers and precision spectral measurement systems. Background Technology
[0002] Waveguide phase arrays (such as arrayed waveguide gratings (AWGs) have broad application prospects in astronomical spectroscopic observation, remote sensing, and precision spectral analysis due to their advantages such as small size, high stability, and ease of integration. However, due to factors such as micro-nano fabrication errors, waveguide length deviations, refractive index inhomogeneities, and packaging stress, waveguide phase arrays inevitably introduce inter-channel phase errors during actual operation.
[0003] The aforementioned phase error directly leads to a decrease in the coherence of the output optical field, thereby causing a decrease in spectral contrast, which severely restricts the application of waveguide phase arrays in the field of high-precision spectral measurement.
[0004] Currently, the main methods for handling phase errors in waveguide phase arrays include the following categories:
[0005] 1) Process optimization methods
[0006] Phase errors can be reduced by improving the precision of photolithography, etching and material deposition, but this method has extremely high requirements for process conditions, is costly and cannot completely eliminate errors;
[0007] 2) On-chip thermal modulation or electro-optic modulation detection methods
[0008] Phase correction can be achieved by introducing thermal modulation or electro-optic modulation structures inside the chip, but such methods are complex, consume a lot of power, and are prone to introducing additional noise, thus limiting stability.
[0009] 3) Offline calibration method
[0010] Post-processing corrections are performed by testing the overall spectral response of the chip, but this method is difficult to achieve accurate characterization and independent compensation of the phase error of each channel.
[0011] Existing technologies generally suffer from problems such as insufficient phase error detection accuracy, complex compensation structures, or difficulty in achieving global optimal compensation. There is still a lack of a universal phase error detection method that is simple in structure, has high detection accuracy, and is applicable to multi-channel waveguide phase arrays. Summary of the Invention
[0012] To address the limitations of existing waveguide phase array phase error detection accuracy and the difficulty in achieving global optimization, this invention provides a high-precision phase error detection method for waveguide phase arrays using a spatial light modulator. This method achieves high-precision phase error detection of waveguide phase arrays without requiring modifications to the waveguide phase array structure, significantly improving the coherence and spectral contrast of the waveguide phase array's optical field.
[0013] To achieve the above objectives, the present invention provides the following technical solution:
[0014] A method for high-precision detection of phase error of waveguide phase array using a spatial light modulator includes the following steps:
[0015] Step 1: Construct a phase modulation and detection system; the phase modulation and detection system includes a spatial light modulator, a waveguide phase array, a camera, and a lens; wherein, the phase modulation system includes a spatial light modulator, and the detection system includes a camera, etc.
[0016] Step 2: The multi-channel beam output from the waveguide phase array is collimated by a lens and then incident on the spatial light modulator;
[0017] Step 3: Guide the beam modulated by the spatial light modulator to the camera to form interference or superimposed light spot patterns;
[0018] Step 4: Acquire the interference or superimposed spot pattern, and obtain the phase error distribution of each channel of the waveguide array based on the pattern inversion;
[0019] Step 5: Based on the phase error distribution, load the corresponding phase compensation map onto the spatial light modulator to achieve static compensation of the phase error of the waveguide phase array, and finally obtain the phase error.
[0020] Furthermore, in step 1, a phase control system is constructed using a first lens, a beam splitter, a second lens, and a spatial light modulator, and a detection system is constructed using a third lens and a camera. The light output from the waveguide phase array is collimated to the phase control system after passing through the first lens, and the light is reflected by the spatial light modulator, reflected by the beam splitter, and then passes through the third lens to the camera of the detection system.
[0021] Furthermore, the multi-channel beam output by the waveguide phase array is collimated by the first lens, and then sequentially passes through the spatial light modulator and the second lens to be focused onto the camera. The waveguide phase array is located at the front focal point of the first lens, and the camera is located at the rear focal point of the second lens. The output beams of each waveguide channel remain spatially independent.
[0022] Furthermore, the light spot pattern formed in step 3 is any one or a combination of a far-field interference pattern, a Fourier surface intensity distribution, or a multi-channel superimposed interference pattern; the phase error inversion method in step 4 includes, but is not limited to, any one of the following: a phase extraction method based on interference fringe displacement; a phase recovery method based on Fourier transform; a phase measurement method based on phase stepping; a phase reconstruction method based on intensity distribution inversion; the static compensation in step 5 is to load a fixed phase compensation map on the spatial light modulator, and its phase error compensation is the global optimal value of the waveguide phase array.
[0023] Furthermore, the phase error is the relative phase error between each output channel of the waveguide array, and the relative phase error uses any one channel or the theoretical ideal phase distribution as a reference.
[0024] Furthermore, the phase error compensation process incorporates an intelligent optimization algorithm, which iteratively optimizes the phase loading distribution of the spatial light modulator to maximize the objective function.
[0025] Furthermore, the objective function includes, but is not limited to, any one or a combination of the following: peak intensity of the main lobe of the output light spot; energy concentration of spectral focusing; spectrometer resolution or spectral line contrast; output light field coherence index; the intelligent optimization algorithm includes, but is not limited to, any one of the following: genetic algorithm; particle swarm optimization algorithm; simulated annealing algorithm; gradient descent optimization algorithm; machine learning-based optimization algorithm; the phase accuracy of the spatial light modulator is not lower than the measurement accuracy of the phase error of the waveguide phase array.
[0026] Furthermore, the spatial light modulator is a reflective liquid crystal spatial light modulator.
[0027] Furthermore, the method is applicable to high-precision detection of phase errors in arrayed waveguide grating spectral chips, integrated photonic waveguide arrays, or other multi-channel waveguide phase arrays.
[0028] Furthermore, the method can be applied to astronomical spectrometers, space exploration payloads, or high-resolution spectral measurement systems.
[0029] Compared with the prior art, the beneficial effects of the present invention are:
[0030] 1) High-precision phase error detection can be achieved without modifying the waveguide phase array structure;
[0031] 2) High-resolution phase modulation is achieved using a spatial light modulator, resulting in high detection accuracy and a large number of applicable channels;
[0032] 3) By combining intelligent optimization algorithms, optimal static detection of global phase error is achieved, effectively improving spectral resolution and energy concentration;
[0033] 4) The system has a simple structure and strong versatility, and can be adapted to different types of waveguide phase arrays;
[0034] 5) Provide key technical support for the miniaturization, high precision and high stability development of high-resolution astronomical spectrometers. Attached Figure Description
[0035] Figure 1 This is the system optical path diagram for Example 1;
[0036] Figure 2 This is the system optical path diagram for Example 2;
[0037] In the diagram: 1. Spatial light modulator; 2. Waveguide phase array; 3. First lens; 4. Second lens; 5. Third lens; 6. Beam splitter; 7. Camera. Detailed Implementation
[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
[0039] This invention provides a method for high-precision detection of phase error in waveguide phase arrays using a spatial light modulator, comprising the following steps:
[0040] Step 1: Construct a phase modulation and detection system;
[0041] Step 2: Collimate the multi-channel beam output from the waveguide phase array and then incident it onto the spatial light modulator;
[0042] Step 3: Guide the beam modulated by the spatial light modulator to the camera to form interference or superimposed light spot patterns;
[0043] The resulting light spot pattern is any one or a combination of far-field interferometry, Fourier surface intensity distribution, or multi-channel superimposed interferometry;
[0044] Step 4: Acquire the interference or superimposed spot pattern, and obtain the phase error distribution of each channel of the waveguide array based on the pattern inversion;
[0045] The phase error inversion method can be a phase extraction method based on interference fringe displacement, a phase recovery method based on Fourier transform, a phase measurement method based on phase stepping, a phase reconstruction method based on intensity distribution inversion, etc.; the phase error is the relative phase error between each output channel of the waveguide array, and the relative phase error uses any one channel or the theoretical ideal phase distribution as a reference.
[0046] Step 5: Based on the phase error distribution, load the corresponding phase compensation map onto the spatial light modulator to achieve static compensation of the phase error of the waveguide phase array, and finally obtain the phase error;
[0047] The static compensation involves loading a fixed phase compensation map onto the spatial light modulator, with the phase error compensation being the globally optimal value of the waveguide phase array. The phase error compensation process incorporates an intelligent optimization algorithm, iteratively optimizing the phase loading distribution of the spatial light modulator to maximize the objective function. The objective function can be one or a combination of the following: the peak intensity of the main lobe of the output spot, the energy concentration of spectral focusing, the spectrometer resolution or spectral contrast, and the coherence index of the output light field. The intelligent optimization algorithm can be any one of the following: genetic algorithm, particle swarm optimization algorithm, simulated annealing algorithm, gradient descent optimization algorithm, or machine learning-based optimization algorithm. The phase modulation accuracy of the spatial light modulator is not lower than the measurement accuracy of the phase error of the waveguide phase array.
[0048] The method is applicable to astronomical spectrometers, space probe payloads, or high-resolution spectral measurement systems.
[0049] Example 1:
[0050] One embodiment of the phase modulation and detection system is shown in Figure 1. The method based on this system includes the following specific steps:
[0051] 1) Deploying the phase error detection device: The waveguide phase array 2, first lens 3, beam splitter 6 (BS), second lens 4, spatial light modulator 1 (SLM), third lens 5, and camera 7 are sequentially deployed according to the structure shown in Figure 1. The coaxial cage-like optical structure formed by the first lens 3, beam splitter 6, second lens 4, and spatial light modulator 1 constitutes the waveguide phase array phase modulation detection system. The third lens 5 is used to image the modulated beam onto the camera 7; the third lens 5 and camera 7 together form the detection system. The spatial light modulator 1 can be a reflective spatial light modulator. This embodiment, based on this device, utilizes the spatial light modulator combined with an intelligent optimization algorithm to perform phase modulation of the waveguide phase array phase error, achieving globally optimal detection of the waveguide phase array phase error. 2) Collimation of the waveguide phase array output beam: The multi-channel beam output from the waveguide phase array 2 is collimated by the first lens 3 before entering the phase modulation detection system. In this step, the output beams of each waveguide channel remain spatially independent, providing conditions for subsequent phase modulation and interferometric detection.
[0052] 3) Phase modulation based on a spatial light modulator: Spatial light modulator 1 is a reflective liquid crystal spatial light modulator with a preset phase modulation pattern loaded on its surface, applying controllable phase modulation to the incident multi-channel beams respectively. The beams reflected by spatial light modulator 1 are reflected by beam splitter 6 and focused or imaged onto the detection surface of camera 7 by third lens 5, thereby forming interference or superimposed light spot patterns of multi-channel beams on camera 7.
[0053] 4) Phase error detection: Camera 7 acquires the light spot pattern and analyzes the interference fringes, intensity distribution, or far-field spot morphology. Using an interferometric pattern analysis algorithm or a light field inversion algorithm, the relative phase error distribution between each output channel of the waveguide phase array 2 is extracted. The phase error is referenced to any one channel or the theoretical ideal phase distribution.
[0054] 5) Static phase error compensation: Based on the detected phase error distribution, a corresponding phase compensation map is constructed and loaded onto the spatial light modulator 1. The spatial light modulator 1 applies a compensation phase opposite to the phase error to each channel beam, thereby achieving static compensation for the phase error of the waveguide phase array 2.
[0055] 6) Global optimal compensation based on intelligent optimization algorithm: In the above compensation process, an intelligent optimization algorithm is introduced to iteratively optimize the phase loading distribution of spatial light modulator 1. The output spot energy concentration, main lobe peak intensity, or spectral resolution is used as the objective function to achieve global optimal compensation of the waveguide phase array phase error. When the objective function reaches a preset threshold or convergence condition, high-precision results of the phase error of each channel are obtained, realizing the detection of the phase error of each channel.
[0056] 7) Verification of compensation effect: After compensation, the light spot pattern on camera 7 is acquired again and compared with the light spot pattern before compensation to verify the phase error compensation effect. Experimental results show that the method of this invention can significantly improve the coherent superposition effect of multi-channel beams and effectively improve the spectral resolution and energy concentration of the waveguide phase array.
[0057] Example 2:
[0058] Another embodiment of the phase modulation and detection system is shown in Figure 2. The method based on this system includes the following specific steps:
[0059] 1) Deploy the phase error detection device, and arrange the waveguide phase array 2, the first lens 3, the spatial light modulator 1, the second lens 4, and the camera 7 in sequence according to the structure shown in Figure 1. Among them, the waveguide phase array 2, the first lens 3, the spatial light modulator 1, the second lens 4, and the camera 7 are aligned on a straight line. The waveguide phase array is located at the front focal point of the first lens 3, and the camera 7 is located at the rear focal point of the second lens.
[0060] 2) Collimation of the waveguide phase array output beam: The multi-channel beam output from waveguide phase array 2 is collimated by the first lens 3, enters the subsequent optical system, and is incident on the effective modulation region of spatial light modulator 1. Then, it is focused onto camera 7 after passing through the second lens 4. In this step, the output beams of each waveguide channel remain spatially independent, providing conditions for subsequent phase modulation and interferometric detection.
[0061] 3) Phase modulation based on a spatial light modulator: Spatial light modulator 1 is a transmissive liquid crystal spatial light modulator with a preset phase modulation pattern loaded on its surface, applying controllable phase modulation to the incident multi-channel beams respectively. The beams transmitted through spatial light modulator 1 are directly focused or imaged onto the detection surface of camera 7 by the second mirror 4, thereby forming interference or superimposed light spot patterns of multi-channel beams on camera 7.
[0062] 4) Phase error detection: Camera 7 acquires the light spot pattern and analyzes the interference fringes, intensity distribution, or far-field spot morphology. Using an interferometric pattern analysis algorithm or a light field inversion algorithm, the relative phase error distribution between each output channel of the waveguide phase array 2 is extracted. The phase error is referenced to any one channel or the theoretical ideal phase distribution.
[0063] 5) Static compensation of phase error: Based on the detected phase error distribution, a corresponding phase compensation map is constructed and loaded onto the spatial light modulator 1. The spatial light modulator 1 applies a compensation phase opposite to the phase error to each channel beam, thereby achieving static compensation of the phase error of the waveguide phase array 2.
[0064] 6) Global optimal compensation based on intelligent optimization algorithm: In the above compensation process, an intelligent optimization algorithm is introduced to iteratively optimize the phase loading distribution of spatial light modulator 1. The output spot energy concentration, main lobe peak intensity, or spectral resolution is used as the objective function to achieve global optimal compensation of the waveguide phase array phase error. When the objective function reaches a preset threshold or convergence condition, high-precision results of the phase error of each channel are obtained, realizing the detection of the phase error of each channel.
[0065] 7) Verification of compensation effect: After compensation, the light spot pattern on camera 7 is acquired again and compared with the light spot pattern before compensation to verify the phase error compensation effect. Experimental results show that the method of this invention can significantly improve the coherent superposition effect of multi-channel beams and effectively improve the spectral resolution and energy concentration of the waveguide phase array.
[0066] The proposed method for high-precision detection of waveguide phase array phase error using a spatial light modulator is simple in structure. It achieves high-precision phase control of the waveguide phase array phase error by combining a spatial light modulator with an intelligent optimization algorithm, and accurately obtains the phase error using an interferogram algorithm. This invention addresses the existing waveguide phase array phase error problem, promoting the development of astronomical spectrometers towards miniaturization, high precision, and high stability, and providing technical support for my country's astronomical spectroscopic observation and space exploration missions.
[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for high-precision detection of phase error of waveguide phase array using a spatial light modulator, characterized in that, Includes the following steps: Step 1: Construct a phase modulation and detection system; the phase modulation and detection system includes a spatial light modulator, a waveguide phase array, a camera, and a lens; wherein, the phase modulation system includes a spatial light modulator, and the detection system includes a camera; Step 2: The multi-channel beam output from the waveguide phase array is collimated by a lens and then incident on the spatial light modulator; Step 3: Guide the beam modulated by the spatial light modulator to the camera to form interference or superimposed light spot patterns; Step 4: Acquire the interference or superimposed spot pattern, and obtain the phase error distribution of each channel of the waveguide array based on the pattern inversion; Step 5: Based on the phase error distribution, load the corresponding phase compensation map onto the spatial light modulator to achieve static compensation of the phase error of the waveguide phase array, and finally obtain the phase error.
2. The method according to claim 1, characterized in that, In step 1, a phase control system is constructed using a first lens, a beam splitter, a second lens, and a spatial light modulator, and a detection system is constructed using a third lens and a camera. The light output from the waveguide phase array is collimated to the phase control system after passing through the first lens. The light is reflected by the spatial light modulator, reflected by the beam splitter, and then passes through the third lens to the camera of the detection system.
3. The method according to claim 1, characterized in that, In step 1, the multi-channel beam output by the waveguide phase array is collimated by the first lens and then sequentially passes through the spatial light modulator and the second lens to be focused onto the camera. The waveguide phase array is located at the front focal point of the first lens, and the camera is located at the rear focal point of the second lens. The output beams of each waveguide channel remain independent in space.
4. The method according to claim 1, characterized in that, The light spot pattern formed in step 3 is any one or a combination of far-field interferometry, Fourier surface intensity distribution, or multi-channel superimposed interferometry; the phase error inversion method in step 4 includes, but is not limited to, any one of the following: phase extraction method based on interference fringe displacement; phase recovery method based on Fourier transform; phase measurement method based on phase stepping. The phase reconstruction method based on intensity distribution inversion; the static compensation in step 5 is to load a fixed phase compensation map on the spatial light modulator, and its phase error compensation is the global optimal value of the waveguide phase array.
5. The method according to claim 1, characterized in that, The phase error is the relative phase error between each output channel of the waveguide array, and the relative phase error uses any one channel or the theoretical ideal phase distribution as a reference.
6. The method according to claim 4, characterized in that, The phase error compensation process introduces an intelligent optimization algorithm, which iteratively optimizes the phase loading distribution of the spatial light modulator to maximize the objective function.
7. The method according to claim 6, characterized in that, The objective function includes, but is not limited to, any one or a combination of the following: peak intensity of the main lobe of the output light spot; energy concentration of spectral focusing; spectrometer resolution or spectral line contrast; output light field coherence index; the intelligent optimization algorithm includes, but is not limited to, any one of the following: genetic algorithm; particle swarm optimization algorithm; simulated annealing algorithm; gradient descent optimization algorithm; machine learning-based optimization algorithm, etc.; the phase modulation accuracy of the spatial light modulator is not lower than the measurement accuracy of the phase error of the waveguide phase array.
8. The method according to claim 1, characterized in that, The spatial light modulator is a reflective liquid crystal spatial light modulator.
9. The method according to claim 1, characterized in that, The method is applicable to high-precision detection of phase errors in arrayed waveguide grating spectral chips, integrated photonic waveguide arrays, or other multi-channel waveguide phase arrays.
10. The method according to any one of claims 1 to 9, characterized in that, The method is applicable to astronomical spectrometers, space probe payloads, or high-resolution spectral measurement systems.