Optical wavefront sensing system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QIANYUAN NATIONAL LABORATORY
- Filing Date
- 2026-03-24
- Publication Date
- 2026-05-29
Smart Images
Figure CN122108548A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical wavefront detection, and in particular to optical wavefront detection systems. Background Technology
[0002] In fields such as optical resolution imaging and astronomical observation, high resolution is required for optical systems, necessitating precise control of the wavefront phase. The wavefront refers to the line (or surface) connecting points with the same vibration phase during light wave propagation; the wavefront phase distribution is a quantitative description of the wavefront shape. In practical applications, the wavefront may be distorted during transmission due to dynamic non-uniform media such as atmospheric turbulence, or static assembly errors, affecting beam focusing or collimation efficiency and thus reducing the resolution of the optical system. To address this, adaptive optics technology establishes a measurement, feedback, and control mechanism. Optical wavefront detection technology measures wavefront distortion, reconstructs the wavefront phase distribution, and the control system feeds the measurement results back to the phase compensation mechanism for precise wavefront compensation, thereby improving the focused beam quality of the optical system.
[0003] Currently, wavefront detection technology is divided into wavefront detection for point targets and wavefront detection for extended targets. Among these, optical wavefront detection for point targets is relatively mature, while wavefront detection technology for extended targets is still less mature. Wavefront detection technology for extended targets includes wavefront detection based on optical field acquisition and wavefront detection based on phase difference methods.
[0004] Among them, the extended target wavefront detection based on light field acquisition originates from the Hartmann sensor wavefront detection method. The Hartmann sensor, based on microlens array segmentation of the wavefront, decomposes complex higher-order aberrations into numerous approximately tilted wavefronts within the microlens unit apertures. These tilted wavefronts cause focus spot shifts; by measuring the shift of the sub-spots, the wavefront slope distribution across the entire aperture can be deduced, thus reconstructing the wavefront distortion. The all-optical camera method is based on a similar approach, calculating wavefront distortion through image shifts. However, this technique suffers from a slow wavefront reconstruction speed because the extended target and phase are not effectively decoupled during detection. The all-optical camera needs to acquire four-dimensional signals of the target's spatial distribution and the light angle distribution, resulting in a large data volume. In contrast, the phase difference method estimates wavefront distortion and the sharp target itself by acquiring images of the focal plane and defocus plane, based on solving a nonlinear optimization problem. However, this technique employs numerical optimization methods, which suffer from local extrema and are susceptible to hardware errors, leading to unstable wavefront reconstruction results.
[0005] There is currently no effective solution to the problems of low wavefront reconstruction speed and unstable reconstruction results in related technologies. Summary of the Invention
[0006] This embodiment provides an optical wavefront detection system to solve the problems of low wavefront reconstruction speed and unstable reconstruction results in related technologies.
[0007] In a first aspect, this embodiment provides an optical wavefront detection system, including a microlens array, an integrated photonic chip, and a data processing unit; wherein: the integrated photonic chip includes a mode-spot converter array, a waveguide transmission network, a multimode interference mixer array, and a photodetector array;
[0008] The modulus converter array is arranged on the input end face of the integrated photonic chip; the optical input port of each modulus converter in the modulus converter array is set to correspond one-to-one with the focal position of each unit microlens in the microlens array.
[0009] The waveguide transmission network connects the output of the mode converter array to the input of the multimode interference mixer array; the waveguides of each channel in the waveguide transmission network form interference aperture pairs in pairs;
[0010] Each multimode interference mixer in the multimode interference mixer array is configured in a one-to-one correspondence with each interference aperture pair; the output terminal of the multimode interference mixer array is connected to the input terminal of the photodetector array;
[0011] The microlens array is used to segment and focus the wavefront to be measured into discrete light spots.
[0012] The mode-spot converter array is used to receive each of the discrete light spots and process each of the discrete light spots into an optical signal that matches the size of the waveguide transmission network;
[0013] The waveguide transmission network is used to transmit the optical signal processed by the mode converter array to the multimode interference mixer array;
[0014] Each multimode interference mixer in the multimode interference mixer array is used to receive two optical signals transmitted by the waveguide corresponding to the interference aperture pair, perform optical interference on the two optical signals, and output four interference signals with a preset phase difference.
[0015] The photodetector array is used to convert the interference signal output by the multimode interference mixer array into an electrical signal;
[0016] The data processing unit is used to receive the electrical signal and perform wavefront reconstruction calculation on the electrical signal to obtain the wavefront phase distribution information of the wavefront to be measured.
[0017] In some embodiments, the microlens array includes multiple unit microlenses of the same size, which are arranged in a two-dimensional arrangement at equal intervals; unit microlenses with the same orientation in the microlens array form lens combinations in pairs, and the baseline length of the lens combinations with the same orientation is consistent.
[0018] In some embodiments, the numerical aperture of the speckle converter array is the same as the numerical aperture of the microlens array.
[0019] In some embodiments, waveguides of adjacent channels in the waveguide transmission network form a pair of interference apertures.
[0020] In some embodiments, the phase differences of the four interference signals output by the multimode interference mixer array include 0 degrees, 90 degrees, 180 degrees, and 270 degrees.
[0021] In some embodiments, the data processing unit mixes the interference signal based on two orthogonal local oscillator signals at 0 degrees and 90 degrees to obtain in-phase and quadrature component signals; calculates the phase difference between the two signals of the interference aperture pair based on the in-phase and quadrature component signals; converts the phase difference into wavefront gradient information based on the microlens baseline length of the microlens array; and reconstructs the wavefront phase distribution information based on the wavefront gradient information.
[0022] In some embodiments, the data processing unit performs numerical difference or integration on the wavefront gradient information corresponding to each pair of interference apertures to fit the wavefront phase distribution information.
[0023] In some embodiments, the data processing unit solves for the coefficients of the preset basis function of the wavefront to be measured based on the wavefront gradient information to obtain the wavefront phase distribution information.
[0024] In some embodiments, the data processing unit calculates the coefficients of the preset basis function of the wavefront to be measured based on the wavefront gradient information, and iteratively optimizes the coefficient calculation results to obtain the wavefront phase distribution information.
[0025] In some embodiments, the data processing unit processes the wavefront gradient information based on a neural network to obtain the wavefront phase distribution information.
[0026] Compared with related technologies, the optical wavefront detection system provided in this embodiment decouples the light intensity signal from the wavefront distortion, directly extracts the spatial phase gradient of the wavefront, and digitally recovers the wavefront distortion. While ensuring high reconstruction accuracy, it also avoids the problems of high redundant sampling and nonlinear optimization extrema. Therefore, it improves the stability of the wavefront detection results and the wavefront reconstruction speed, realizing real-time wavefront detection in extended target scenarios.
[0027] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description
[0028] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0029] Figure 1 This is a schematic diagram of the structure of the optical wavefront detection system according to an embodiment of this application;
[0030] Figure 2a This is one arrangement pattern of the microlens array in the embodiments of this application;
[0031] Figure 2b This is yet another arrangement pattern of the microlens array in the embodiments of this application;
[0032] Figure 3a This is a schematic diagram of the input and output ports of a multimode interference mixer;
[0033] Figure 3b This is a schematic diagram of a multimode interference mixer. Detailed Implementation
[0034] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.
[0035] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these” used in this application do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to these processes, methods, products, or devices. Words such as “connected,” “linked,” and “coupled” used in this application are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. Normally, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," "third," etc., used in this application are merely to distinguish similar objects and do not represent a specific order of objects.
[0036] In this embodiment, an optical wavefront detection system is provided. Figure 1 This is a schematic diagram of the optical wavefront detection system 10 in this embodiment, as shown below. Figure 1 As shown, the optical wavefront detection system 10 may specifically include: a microlens array 12, an integrated photonic chip 14, and a data processing unit 16; wherein: the integrated photonic chip 14 includes a mode converter array 141, a waveguide transmission network 142, a multimode interference mixer array 143, and a photodetector array 144; the mode converter array 141 is arranged on the input end face of the integrated photonic chip 14; the optical input port of each mode converter in the mode converter array 141 corresponds one-to-one with the focal position of each unit microlens in the microlens array 12; the waveguide transmission network 142 connects the output end of the mode converter array 141 to the input end of the multimode interference mixer array 143; the waveguides of each channel in the waveguide transmission network 142 form interference aperture pairs in pairs; each multimode interference mixer in the multimode interference mixer array 143 corresponds one-to-one with each interference aperture pair; the output end of the multimode interference mixer array 143 is connected to the input end of the photodetector array 144;
[0037] The microlens array 12 is used to segment and focus the wavefront to be measured into discrete light spots; the mode-spot converter array 141 is used to receive each discrete light spot and process each discrete light spot into an optical signal that matches the size of the waveguide transmission network 142; the waveguide transmission network 142 is used to transmit the optical signal processed by the mode-spot converter array 141 to the multimode interference mixer array 143; each multimode interference mixer in the multimode interference mixer array 143 is used to receive two optical signals transmitted by the waveguides of the corresponding interference aperture pair, perform optical interference on the two optical signals, and output four interference signals with a preset phase difference; the photodetector array 144 is used to convert the interference signal output by the multimode interference mixer array 143 into an electrical signal; the data processing unit 16 is used to receive the electrical signal and perform wavefront reconstruction calculation on the electrical signal to obtain the wavefront phase distribution information of the wavefront to be measured.
[0038] Specifically, the microlens array 12 can be composed of several unit microlenses of the same size arranged in a two-dimensional pattern with equal spacing. Figure 2a , Figure 2b These are the arrangement patterns of the microlens array 12 in this embodiment. For example... Figure 2a As shown, a microlens array can be constructed by closely packed hexagonal unit microlenses; such as Figure 2b As shown, the microlens array can be constructed by closely packed square unit microlenses. The fabrication methods of this microlens array 12 include, but are not limited to, laser direct writing, nanoimprinting, inkjet printing, and etching processes. The size of the microlens array and the diameter of the unit microlenses can be matched according to the beam size of the wavefront to be measured and the pre-estimated wavefront distortion. Furthermore, for strong turbulence (shorter atmospheric coherence length), a smaller microlens diameter can be selected, while for weak turbulence (longer atmospheric coherence length), a larger microlens diameter can be selected. The microlens diameter can be selected on the order of micrometers or millimeters.
[0039] Integrated photonic chip technology is an emerging platform technology that, by drawing inspiration from electronic integrated circuits, integrates or co-packages optical components such as modulators, waveguides, and detectors on a single substrate. This enables the miniaturization and integration of space optical systems, thereby reducing system size, weight, and power consumption. With the development of optical chip device structures, a series of specialized unit devices, such as those for beam splitting, interference, and signal modulation, have emerged to meet various application requirements. In this embodiment, the integrated photonic chip 14 may include a mode converter array 141, a waveguide transmission network 142, a multimode interference mixer array 143, and a photodetector array 144. The mode converter array 141 comprises several mode converters, which are passive coupling structures used to match the optical field mode size and mode distribution between the microlens array and the integrated photonic chip. A gradual change in the light spot size is achieved through a gradient structure, reducing mode mismatch loss. The speckle converter array 141 is disposed on the input end face of the integrated photonic chip 14. Its number and arrangement spacing are set one-to-one with the microlens array 12. The speckle converter array 141 includes multiple speckle converters. The light inlet of each speckle converter is directly opposite the focal position of the corresponding unit microlens. In this way, the speckle converter array 141 can efficiently receive the light spot focused by the microlens array 12.
[0040] The waveguide transmission network 142 includes several waveguides. A waveguide is an optical structure that uses total internal reflection or refractive index difference to constrain the transmission of a light field. It can confine light waves to a specific region and allow them to propagate with low loss along a predetermined direction, serving as the optical path for transmitting optical signals. The waveguide transmission network 142 is connected between the mode converter array 141 and the multimode interference mixer array 143. By designing the waveguide length, it is ensured that the optical path lengths of adjacent channels in the waveguide transmission network 142 are the same, thus eliminating wavefront errors in the optical signal during transmission. The waveguides leading out of the waveguide transmission network 142 are connected in pairs to form interference aperture pairs.
[0041] The multimode interference mixer array 143 includes several multimode interference mixers. A multimode interference mixer is an integrated optical device based on the self-imaging effect in a multimode waveguide. The input terminal of each multimode interference mixer in the multimode interference mixer array 143 is connected to a set of interference aperture pairs of the waveguide transmission network 142. That is, the input terminal of one multimode interference mixer is connected to the waveguides of two channels leading out from the waveguide transmission network 142. Each multimode interference mixer has two input terminals and four output terminals. Figure 3a This is a schematic diagram of the input and output ports of a multimode interference mixer. Figure 3b This is a schematic diagram of a multimode interference mixer. (Combined with...) Figure 3a and Figure 3bA multimode interferometric mixer can be composed of a 1×2 multimode interferometer 301 (MMI for short), a 90-degree phase shifter 302, and a 2×2 multimode interferometer 303. The MMI mixes the optical signals from the two input channels and outputs four optical signals with specific phase differences, thereby reconstructing the amplitude and phase information of the signal. This MMI can employ architectures such as 2×4 MMI, 4×4 MMI, dual-drive Mach-Zehnder modulators, and 90-degree phase modulators.
[0042] The photodetector array 144 can be fabricated on the integrated photonic chip 14 using an on-chip heterogeneous integration method, or it can be coupled to the output end face of the integrated photonic chip using an optical fiber array to achieve off-chip connectivity. The photodetector array can be based on photodiodes; for example, ordinary photodiodes (PDs) or avalanche diodes (APDs) can be selected to form the photodetector array depending on the intensity of the optical signal. The number of detectors in the photodetector array 144 is adapted to the number of output ports of the multimode interference mixer in the aforementioned multimode interference mixer array 143.
[0043] In the application, the microlens array 12 receives the distorted wavefront to be measured, splits the large incident beam of the wavefront into discrete spots, and focuses them into individual light spots. In the integrated photonic chip 14, the mode-spot converter array 141 at the input end performs optical coupling on the light spots so that they enter the integrated photonic chip; the waveguide transmission network 142 guides the specifically arranged light spots to the multimode interference mixer array 143 for mixing and interference; the interference signal output by the multimode interference mixer is received by the photodetector array 144, thereby completing the coupling, transmission, and interference of optical signals within the integrated photonic chip.
[0044] Specifically, the mode converter array 141 compresses or converts the large-mode light spot output from the microlens array 12 in free space into a guided wave mode field that matches the size of the waveguide transmission network 142 of the integrated photonic chip, thereby achieving coupling of the optical signal from space to the chip. The waveguide transmission network 142 transmits the optical signals coupled into each channel of the integrated photonic chip via the mode converter array to each multimode interference mixer in the multimode interference mixer array 143 with low loss. Each multimode interference mixer in the multimode interference mixer array 143, as the core interference unit, receives two optical signals and performs optical mixing. Utilizing the multimode interference effect, it outputs four interference signals with fixed phase differences at the four output terminals. Specifically, these can be four interference signals with 0 degrees, 90 degrees, 180 degrees, and 270 degrees to completely preserve the in-phase and quadrature components of the interference light, thus facilitating subsequent reconstruction of the phase difference between the two optical signals. The two optical signals that undergo optical interference by the multimode interference mixer can be optical signals from adjacent channels. Each photodetector in the photodetector array 144 converts the four interference signals into electrical signals. Finally, the data processing unit 16, electrically connected to the photodetector array 144, receives the electrical signals and performs wavefront reconstruction. The data processing unit 16 can be any unit capable of signal reception and processing, and able to deploy and run wavefront reconstruction algorithms. This data processing unit 16 can pre-deploy general wavefront distortion gradient information extraction algorithms and wavefront distortion reconstruction algorithms to ultimately calculate the complete wavefront phase distribution information.
[0045] In this embodiment, an integrated photonic chip 14 is introduced into wavefront detection. By coupling the microlens array 12 with the mode-spot converter array 141 of the integrated photonic chip, optical signal coupling from space to the chip is successfully achieved. Furthermore, an on-chip multimode interference mixer array 143 is used to replace the traditional spatial optical path interferometer to perform signal interference. This integrated waveguide approach avoids the large size of the spatial optical path system and phase errors caused by temperature differences and jitter during transmission. Thus, deep integration of the wavefront sensor is achieved. In this embodiment, the integrated photonic chip 14 is used as the carrier for optical signal transmission and processing. The interference of the optical signal occurs inside the integrated photonic chip 14 (such as in a 2×4 MMI waveguide) rather than in the free space optical path. The integrated photonic chip 14 isolates free space disturbances, thereby effectively isolating external vibrations and environmental temperature differences. This avoids the influence of related disturbances on the optical path, making the optical wavefront detection system insensitive to external vibrations, temperature, and airflow disturbances. As a result, the optical wavefront detection system can operate stably in high-vibration environments such as vehicle platforms and airborne platforms, avoiding the drawbacks of traditional interferometric systems that require frequent calibration and improving the accuracy of wavefront detection results.
[0046] Furthermore, compared to related technologies that use CCD / CMOS fundamental wavefront sensors such as all-optical cameras and Hartmann sensors, this embodiment can directly acquire interference signals through a photodetector array (photodiode), reducing the amount of data processing and increasing the data processing speed. Moreover, the optical wavefront detection system 10 of this embodiment has a simple structure, high integration, and low computational requirements for subsequent algorithm processing, thus possessing good industrialization and applicability.
[0047] Therefore, the optical wavefront detection system 10 proposed in this embodiment addresses the common technical defects in wavefront detection of extended targets in related technologies. It utilizes the waveguide connection interference characteristics of an integrated photonic chip, and through spatial segmented sampling and interference with a specifically selected local aperture pair, it achieves decoupling of the light intensity signal and wavefront distortion. This directly extracts the spatial phase gradient of the wavefront and digitally reconstructs the wavefront distortion. While ensuring high reconstruction accuracy, it also avoids the problems of high redundant sampling and nonlinear optimization extrema. Thus, it solves the problems of unstable detection results and low speed in wavefront detection of extended targets in related technologies, breaks through the technical bottleneck of related technologies, improves the stability of wavefront detection results and data processing speed, and realizes real-time wavefront detection in extended target scenarios.
[0048] In one embodiment, the microlens array 12 includes multiple unit microlenses of the same size, arranged in a two-dimensional configuration with equal spacing. Unit microlenses with the same orientation in the microlens array 12 form lens combinations in pairs, and the baseline length of these lens combinations is consistent. This baseline length is the spatial distance between two unit microlenses within the lens combination. When the unit microlenses are arranged in pairs to form lens combinations, corresponding to the subsequent interference aperture, it is necessary to ensure that the baseline length of all lens combinations facing the same direction is consistent, thereby achieving accurate wavefront detection.
[0049] In another embodiment, the numerical aperture (NA) of the modulator array 141 is the same as that of the microlens array 12. The NA of the modulator array 141 is the angular range of light emitted by each modulator in the array, and the NA of the microlens array 12 is the angular range of light emitted by each unit microlens in the array. In this embodiment, the NA of the modulator is set to be the same as that of the microlens array, and the light spot of each unit microlens enters the waveguide through a single channel after coupling, thus ensuring good coupling efficiency.
[0050] In one embodiment, waveguides of adjacent channels in the waveguide transmission network 142 form a pair of interference apertures. In this embodiment, inter-channel interference is achieved using an integrated photonic chip. Adjacent channels are selected as interference aperture pairs, and the interference is transmitted via waveguides to a multimode interferometric mixer to provide the data basis for wavefront reconstruction.
[0051] Furthermore, in one embodiment, the phase differences of the four interference signals output by the multimode interference mixer array 143 include 0 degrees, 90 degrees, 180 degrees, and 270 degrees. By outputting optical signals with specific phase differences of 0 degrees, 90 degrees, 180 degrees, and 270 degrees, the original amplitude and phase information of the optical signal can be completely restored, thereby accurately realizing wavefront distortion reconstruction.
[0052] In one embodiment, the data processing unit 16 mixes the interference signal based on two orthogonal local oscillator signals at 0 degrees and 90 degrees to obtain in-phase and quadrature component signals; calculates the phase difference between the two signals of the interference aperture pair based on the in-phase and quadrature component signals; converts the phase difference into wavefront gradient information based on the microlens baseline length of the microlens array; and reconstructs the wavefront phase distribution information based on the wavefront gradient information.
[0053] The wavefront gradient is a vector representing the rate of change of the direction of the fastest phase change on the wavefront. In this embodiment, the data processing unit calculates the phase signal based on the mixer interference phase signal solution method. Specifically, it mixes the interference signal with two orthogonal local oscillator signals at 0 degrees and 90 degrees to obtain in-phase and quadrature component signals (I and Q signals). Then, it demodulates the in-phase and quadrature component signals (arctan(Q / I)) to calculate the phase, which is the phase difference between the two signals of the interference aperture pair. The phase difference is then divided by the baseline length of the microlens array to obtain the wavefront gradient information. Finally, using the wavefront gradient information, based on gradient methods, pattern methods, hybrid optimization methods, or deep learning, the discrete gradient information is accurately pieced together or fitted to form a continuous wavefront phase surface, obtaining the wavefront phase distribution information and completing the wavefront distortion reconstruction.
[0054] This embodiment acquires interference signals based on a photodetector array and simplifies the calculation of wavefront gradient to basic arithmetic operations of a few channels through I / Q demodulation. Compared with the low computational efficiency caused by the need to process a large amount of data in related technologies, this embodiment can achieve faster and more efficient wavefront detection.
[0055] In some embodiments, the data processing unit 16 performs numerical difference or integration on the wavefront gradient information corresponding to each pair of interference apertures to fit the wavefront phase distribution information. After obtaining the wavefront gradient information, the data processing unit can perform numerical difference or integration based on the gradient method, using the wavefront gradient information of adjacent channels, to fit the wavefront phase point by point. Specifically, the discrete wavefront gradient information (e.g., the slopes in the x and y directions) corresponding to each sub-aperture in the microlens array is used as input. During processing, the entire wavefront is divided into several grids (corresponding to sub-apertures). For the wavefront gradient information measured in each grid, the phase information of each grid point is calculated point by point using numerical difference or integration, starting from a point and utilizing the slope difference between adjacent sub-apertures, ultimately obtaining the continuous phase distribution information on the grid.
[0056] In some embodiments, the data processing unit 16 calculates the coefficients of the preset basis functions of the wavefront under test based on the wavefront gradient information to obtain the wavefront phase distribution information. The data processing unit can use a linear combination of basis functions such as Zernike polynomials to represent the mathematical form of the wavefront based on the mode method, and reconstruct the wavefront phase distribution information by substituting the wavefront gradient information into the equation to calculate the coefficients in the basis functions.
[0057] In some embodiments, the data processing unit 16 calculates the coefficients of the preset basis function of the wavefront to be measured based on the wavefront gradient information, and iteratively optimizes the coefficient calculation results to obtain the wavefront phase distribution information. Specifically, the data processing unit can use a hybrid optimization method, taking the results obtained by the above-mentioned mode method as initial values, and then optimizing the initial values through an iterative optimization algorithm (such as ASPGD) to obtain the final wavefront phase distribution information.
[0058] In some embodiments, the data processing unit 16 processes the wavefront gradient information based on a neural network to obtain wavefront phase distribution information. Specifically, wavefront phase distribution information can be learned and inverted from the light spot image based on neural networks such as U-Net, FF-Net, and Transformer, combined with wavefront gradient information.
[0059] It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. All other embodiments derived by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.
[0060] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.
[0061] Obviously, the accompanying drawings are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar situations based on these drawings without any creative effort. Furthermore, it is understood that although the work done in this development process may be complex and lengthy, for those skilled in the art, certain design, manufacturing, or production modifications made based on the technical content disclosed in this application are merely conventional technical means and should not be considered as insufficient disclosure of this application.
[0062] The term "embodiment" in this application refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply that it is mutually exclusive with or independent of other embodiments. It will be clearly or implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.
[0063] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.
Claims
1. An optical wavefront detection system, characterized in that, It includes a microlens array, an integrated photonic chip, and a data processing unit; wherein: the integrated photonic chip includes a mode-spot converter array, a waveguide transmission network, a multimode interference mixer array, and a photodetector array; The modulus converter array is arranged on the input end face of the integrated photonic chip; the optical input port of each modulus converter in the modulus converter array is set to correspond one-to-one with the focal position of each unit microlens in the microlens array. The waveguide transmission network connects the output of the mode converter array to the input of the multimode interference mixer array; the waveguides of each channel in the waveguide transmission network form interference aperture pairs in pairs; Each multimode interference mixer in the multimode interference mixer array is configured in a one-to-one correspondence with each interference aperture pair; the output terminal of the multimode interference mixer array is connected to the input terminal of the photodetector array; The microlens array is used to segment and focus the wavefront to be measured into discrete light spots. The mode-spot converter array is used to receive each of the discrete light spots and process each of the discrete light spots into an optical signal that matches the size of the waveguide transmission network; The waveguide transmission network is used to transmit the optical signal processed by the mode converter array to the multimode interference mixer array; Each multimode interference mixer in the multimode interference mixer array is used to receive two optical signals transmitted by the waveguide corresponding to the interference aperture pair, perform optical interference on the two optical signals, and output four interference signals with a preset phase difference. The photodetector array is used to convert the interference signal output by the multimode interference mixer array into an electrical signal; The data processing unit is used to receive the electrical signal and perform wavefront reconstruction calculation on the electrical signal to obtain the wavefront phase distribution information of the wavefront to be measured.
2. The optical wavefront detection system according to claim 1, characterized in that, The microlens array includes multiple unit microlenses of the same size, and the unit microlenses are arranged in two dimensions at equal intervals; the unit microlenses with the same orientation in the microlens array form lens combinations in pairs, and the baseline length of the lens combinations with the same orientation is consistent.
3. The optical wavefront detection system according to claim 1, characterized in that, The numerical aperture of the speckle converter array is the same as that of the microlens array.
4. The optical wavefront detection system according to claim 1, characterized in that, In the waveguide transmission network, waveguides of adjacent channels form a pair of interference apertures.
5. The optical wavefront detection system according to claim 1, characterized in that, The phase differences of the four interference signals output by the multimode interference mixer array include 0 degrees, 90 degrees, 180 degrees and 270 degrees.
6. The optical wavefront detection system according to claim 1 or 5, characterized in that, The data processing unit mixes the interference signal based on two orthogonal local oscillator signals at 0 degrees and 90 degrees to obtain in-phase and quadrature component signals; and calculates the phase difference between the two signals of the interference aperture pair based on the in-phase and quadrature component signals. Based on the baseline length of the microlenses in the microlens array, the phase difference is converted into wavefront gradient information; based on the wavefront gradient information, wavefront phase distribution information is reconstructed.
7. The optical wavefront detection system according to claim 6, characterized in that, The data processing unit performs numerical difference or integration on the wavefront gradient information corresponding to each pair of interference apertures to fit the wavefront phase distribution information.
8. The optical wavefront detection system according to claim 6, characterized in that, The data processing unit calculates the coefficients of the preset basis function of the wavefront to be measured based on the wavefront gradient information to obtain the wavefront phase distribution information.
9. The optical wavefront detection system according to claim 6, characterized in that, The data processing unit calculates the coefficients of the preset basis function of the wavefront to be measured based on the wavefront gradient information, and iteratively optimizes the coefficient calculation results to obtain the wavefront phase distribution information.
10. The optical wavefront detection system according to claim 6, characterized in that, The data processing unit processes the wavefront gradient information based on a neural network to obtain the wavefront phase distribution information.