A wideband optical switch channel allocation system and method for a computing spectrometer

Abstract

The application discloses a wide-band optical switch channel distribution system and method for a computing spectrometer, and belongs to the technical field of spectrum measurement. The system comprises an input coupling module, an optical switch module, N polarization-maintaining fiber transmission links, N output coupling modules, an optical power monitoring module and a control and calibration module. The input coupling module receives a wide-spectrum to-be-measured light signal and couples the light signal to a polarization-maintaining fiber; the optical switch module time-switches the wide-spectrum to-be-measured light signal to one of N output ports; the N polarization-maintaining fiber transmission links polarization-maintain transmission of the light signal to corresponding on-chip spectrum analysis channels; and the control and calibration module controls channel switching and performs closed-loop position calibration according to a monitoring signal. The application decomposes a full-band high-resolution detection problem into multiple narrow-band sub-problems through band segmentation, combines full-link polarization-maintaining transmission and closed-loop calibration, realizes the consideration of wide-band coverage and high spectral resolution, and guarantees the determinacy of a sampling matrix and the long-term stability of channel switching.

Description

Technical Field

[0001] This invention relates to the field of spectral measurement technology, and in particular to a wideband optical switch channel allocation system and method for computational spectrometers. Background Technology

[0002] Computational spectrometers (also known as computational reconstructed spectrometers) acquire spectral information from a greater number of wavelengths with fewer samplings by combining coded sampling and numerical reconstruction. This is a crucial technological approach for miniaturizing and integrating spectrometers. However, in wide-band spectral measurement scenarios, existing optical front-end solutions for computational spectrometers suffer from the following main technical shortcomings.

[0003] (a) Single-channel wideband filtering scheme: This scheme uses a single tunable filter to achieve full-band scanning through a wide range of tuning. Due to the inherent trade-off between the free spectral range and the quality factor, this type of scheme has to sacrifice spectral resolution when covering a wide band, resulting in degraded filter contrast and worsened sampling matrix condition number.

[0004] (ii) Multi-channel parallel filtering scheme: Multiple filter arrays designed with different center wavelengths are integrated on the chip, with each filter covering a sub-band. This type of scheme usually uses a beam splitter to equally distribute the input light to each channel, but it does not consider the actual optical power distribution and filter response differences of each sub-band, resulting in uneven reconstruction quality across the entire band.

[0005] (III) Wavelength Division Multiplexing Front-End Solution: Wavelength division multiplexing devices such as arrayed waveguide gratings are used to pre-separate different wavelength components before sending them into the corresponding channels. The channel division of this type of solution is fixed by the physical structure of the device, and the band boundaries and sampling strategies cannot be dynamically adjusted according to measurement requirements.

[0006] (iv) Exploration of the application of optical switches in computational spectrometers: Existing schemes utilize multi-stage optical switch arrays to select different broadband shaping units and cascade them to obtain a series of broadband shaping devices with different transfer functions for global sampling (e.g., CN114563086A). However, in this type of scheme, each shaping device still covers the entire band. Its core lies in enhancing the randomness of the transfer function to improve the orthogonality of the sampling matrix. It does not physically reduce the dimensionality of the broadband band, and the inherent contradiction between broadband coverage and high resolution has not been substantially resolved.

[0007] (v) Lack of polarization management in optical transmission links: Existing solutions mostly use standard quartz single-mode fiber. Optical switches and filtering units usually have polarization-sensitive characteristics. Random changes in polarization state during transmission can lead to instability of the sampling matrix and affect the accuracy of spectral reconstruction.

[0008] To address the aforementioned issues, existing technologies lack a systematic solution that can achieve effective dimensionality reduction and segmentation across a wide band at the optical front end of a computational spectrometer, while simultaneously ensuring the polarization stability of the transmission link and the long-term reliability of channel switching. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a wideband optical switch channel allocation system and method for computational spectrometers. This system effectively reduces the dimensionality of the wideband at the optical front end of the computational spectrometer, enabling each sub-channel to achieve high-resolution detection within a narrower band. Simultaneously, it ensures the stability of the sampling matrix and the long-term reliability of channel switching through end-to-end polarization-preserving transmission and closed-loop position calibration. This achieves the goal of balancing wideband coverage with high spectral resolution and synergistically improving system measurement accuracy and long-term stability.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows: A broadband optical switch channel allocation system for computational spectrometers includes: The input coupling module is used to receive the broadband optical signal under test and couple it into the polarization-maintaining fiber; An optical switch module has one common input port and N output ports, used to time-division switch the broadband optical signal under test input via the input coupling module to any of the N output ports for output, where N is an integer greater than or equal to 2; the optical switch module includes a microlens and an input collimator and N output collimators respectively disposed on the incident optical path side and the outgoing optical path side of the microlens; N independent polarization-maintaining fiber transmission links, one end of each polarization-maintaining fiber transmission link is connected to one output port of the optical switch module, used to transmit the optical signal output by the optical switch module with polarization maintenance. N output coupling modules, each of which is located at the other end of a polarization-maintaining fiber transmission link, are used to couple the optical signal output from the polarization-maintaining fiber transmission link to an on-chip spectral analysis channel of a computational spectrometer. An optical power monitoring module is installed on each of the polarization-maintaining optical fiber transmission links to monitor the coupled optical power of the corresponding transmission link in real time. The control and calibration module is connected to the optical switch module and the optical power monitoring module respectively, and is used to control the channel switching of the optical switch module and perform closed-loop position calibration of the optical switch module according to the monitoring signal of the optical power monitoring module.

[0011] In the above scheme, the optical switch module is a 1×N type optical switch based on microelectromechanical systems, which realizes the switching of the input light spot between different output ports by electrically driving the two-dimensional angular deflection of the microlens.

[0012] In the above scheme, the polarization-maintaining fiber transmission link uses sulfide glass polarization-maintaining fiber or fluoride glass polarization-maintaining fiber.

[0013] In the above scheme, the input optical fiber of the input coupling module is a polarization-maintaining fiber, and its slow axis is aligned with the slow axis of the polarization-maintaining pigtail at the input end of the optical switch module.

[0014] In the above scheme, polarization compensation elements are respectively provided in the optical paths between the input collimator and the microlens, and between the microlens and each of the output collimators.

[0015] In the above scheme, each of the on-chip spectral analysis channels includes a filtering unit optimized for the corresponding sub-band.

[0016] In the above scheme, the optical power monitoring module is provided at the end of each polarization-maintaining fiber transmission link near the optical switch module. The optical power monitoring module includes a beam splitter and a photodetector. The beam splitter is used to split a portion of the optical signal in the corresponding transmission link and guide it to the photodetector.

[0017] A method for allocating broadband optical switch channels for computational spectrometers includes the following steps: Step 1: Based on the wavelength range of the broadband optical signal to be tested, divide the entire band into N sub-bands, and assign each sub-band to an independent detection channel, where N is an integer greater than or equal to 2; Step 2: Drive the optical switch module to switch to each detection channel in sequence, and record the optical power reference value and the corresponding driving voltage of each detection channel; Step 3: According to the preset channel switching sequence, control the optical switch module to switch the input broadband optical signal to each detection channel in sequence. After transmission through the polarization-maintaining fiber transmission link and coupling through the output coupling module of each detection channel, the signal is output to the corresponding on-chip spectral analysis channel. Step 4: After each switch to the target detection channel, monitor the coupled optical power of the detection channel in real time, compare the monitored value with the optical power reference value of the detection channel recorded in Step 2, and if the deviation exceeds the preset tolerance range, automatically adjust the driving voltage of the optical switch module until the monitored value returns to the optical power reference value range.

[0018] In the above scheme, in step 1, an overlap area is reserved between each adjacent sub-band.

[0019] In the above scheme, in step 4, the automatic adjustment of the driving voltage of the optical switch module adopts a gradient search method, gradually adjusting the driving voltage along the upward direction of the optical power gradient until the coupled optical power is restored to the range of the optical power reference value.

[0020] Through the above technical solution, the broadband optical switch channel allocation system and method for computational spectrometers provided by the present invention have the following beneficial effects: (i) Effectively resolve the inherent contradiction between wideband coverage and high spectral resolution This invention utilizes an optical switch channel allocation mechanism to sequentially distribute the broadband optical signal to be tested to multiple independent detection channels according to the band requirements at the optical front end. Each channel only needs to perform filtering and detection within its corresponding narrow sub-band, compressing the equivalent spectral bandwidth to 1 / N of the full band. This transforms a challenging full-band high-resolution detection problem into multiple sub-problems that can easily achieve high resolution within narrower bands, achieving a balance between broadband coverage and high spectral resolution at the system level.

[0021] (ii) Flexible and configurable band division This invention uses an optical switch module as the core device for channel selection. The channel switching order and sequence can be flexibly configured by the control and calibration module according to the measurement task, overcoming the limitation that the channel division of existing wavelength division multiplexing devices is fixed by physical structure and cannot be dynamically adjusted. At the same time, an overlap area is reserved between each adjacent sub-band, providing redundant space for intensity matching calibration for subsequent spectral stitching.

[0022] (III) Achieve wideband, low-loss, polarization-maintaining transmission to ensure the determinism of the sampling matrix. This invention uses sulfide glass polarization-maintaining fiber or fluoride glass polarization-maintaining fiber as the transmission medium to achieve low-loss transmission in the short-wave infrared band while maintaining polarization stability. The end-to-end polarization-maintaining design ensures that the polarization state is transmitted to the on-chip spectral analysis channel without rotation, making the sampling matrix a deterministic matrix, eliminating the time-varying nature of the matrix introduced by random polarization changes, and ensuring the consistency of coded sampling and the accuracy of spectral reconstruction.

[0023] (iv) Closed-loop position calibration ensures long-term stability of channel switching This invention introduces a closed-loop position feedback calibration mechanism based on real-time optical power monitoring. After each channel switch, the monitored optical power is compared with the calibration reference value. When the deviation exceeds the tolerance, the driving voltage is automatically fine-tuned until the optimal coupling efficiency is restored. This ensures the high repeatability of the optical switch module throughout its entire life cycle and over a wide temperature range, providing physical consistency assurance for multi-channel spectral data splicing.

[0024] (v) The system is modular and highly scalable. In this invention, the optical switch channel allocation system is an independent front-end module that is connected to the subsequent on-chip analysis module via a standardized polarization-maintaining fiber interface. Increasing the measurement band only requires expanding the number of output ports and corresponding links of the optical switch module, without modifying the existing modules, thus providing strong system scalability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0026] Figure 1 This is a schematic diagram of a wideband optical switch channel allocation system for computational spectrometers disclosed in an embodiment of the present invention. Detailed Implementation

[0027] 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.

[0028] This invention provides a broadband optical switch channel allocation system and method for computational spectrometers, with specific embodiments as follows: I. System Structure As attached Figure 1 As shown, this invention proposes a broadband optical switch channel allocation system for computational spectrometers. This system serves as the optical front-end preprocessing unit of the computational spectrometer, positioned between the light source under test and the subsequent on-chip spectral analysis channels. The system as a whole comprises an input coupling module, an optical switch module, N polarization-maintaining fiber transmission links, N output coupling modules, an optical power monitoring module, and a control and calibration module.

[0029] (a) Input coupling module The input coupling module receives the broadband optical signal under test and couples it into the polarization-maintaining fiber. The input coupling module includes an optical fiber collimator, whose input fiber is a polarization-maintaining fiber. The slow axis of this polarization-maintaining fiber is precisely aligned with the slow axis of the polarization-maintaining pigtail at the input end of the optical switch module to ensure that the optical signal entering the optical switch module has a stable linear polarization state. The input fiber uses either sulfide glass or fluoride glass polarization-maintaining fiber, which exhibits low-loss transmission characteristics in the short-wave infrared band.

[0030] (ii) Optical switch module The optical switch module has one common input port and N output ports (N is an integer greater than or equal to 2), which are used to time-division switch the broadband optical signal under test input via the input coupling module to any of the N output ports for output.

[0031] The optical switch module employs a 1×N type optical switch based on microelectromechanical systems (MEMS), comprising a microlens and input collimators and N output collimators respectively located on the incident and output optical paths of the microlens. This module achieves two-dimensional angular deflection by electrically driving the microlens, precisely reflecting the input light spot to the fiber collimator at the selected output port, thereby switching the input broadband light to the corresponding transmission link. This module features low insertion loss, low crosstalk, and weak wavelength dependence, and can operate stably across the entire shortwave infrared band.

[0032] Polarization compensation elements are provided in the optical paths between the input collimator and the microlens, and between the microlens and each output collimator, to correct polarization distortion during free space propagation and ensure that the optical signal entering the subsequent polarization-maintaining fiber has a stable linear polarization state.

[0033] (III) Multi-channel polarization-maintaining fiber optic transmission link The system contains N independent polarization-maintaining fiber transmission links. One end of each polarization-maintaining fiber transmission link is connected to one output port of the optical switch module to transmit the optical signal output by the optical switch module while maintaining polarization.

[0034] Each polarization-maintaining fiber transmission link uses either sulfide glass or fluoride glass polarization-maintaining fiber. The core material and stress zone structure have been optimized, resulting in low transmission loss and high polarization extinction ratio in the short-wave infrared band. Polarization-maintaining fiber connectors are installed at both ends of the fiber. The keyway structure inside the connectors ensures precise alignment of the fiber's slow axis with the polarization axis of the output end of the optical switch module and the polarization axis of the input end of the output coupling module, achieving polarization-maintaining transmission throughout the entire link.

[0035] Each on-chip spectral analysis channel contains a filter unit optimized for the corresponding sub-band, such as a micro-ring resonator, an asymmetric Mach-Zehnder interferometer, or a random Bragg grating. Its design parameters (such as resonant cavity length, coupling coefficient, etc.) are optimized according to the wavelength range of the corresponding sub-band to ensure high resolution and high filtering contrast in each sub-band.

[0036] (iv) Output coupling module The system comprises N output coupling modules, each located at the other end of a polarization-maintaining fiber transmission link. These modules couple the optical signal output from the polarization-maintaining fiber transmission link to an on-chip spectral analysis channel of the computational spectrometer. The output coupling modules can employ end-face coupling or vertical coupling, and are optimized for the short-wave infrared band. A precision adjustment mechanism at the coupling interface ensures the alignment accuracy and long-term stability between the fiber and the on-chip waveguide. The output coupling modules also ensure polarization axis alignment between their output and the input of the on-chip spectral analysis channel.

[0037] (v) Optical power monitoring module Optical power monitoring modules are installed on each polarization-maintaining fiber transmission link to monitor the coupled optical power of the corresponding transmission link in real time. Specifically, an optical power monitoring module is installed at the end of each polarization-maintaining fiber transmission link closest to the optical switch module. This optical power monitoring module includes a beam splitter and a photodetector. The beam splitter separates a portion of the optical signal (e.g., 1%~5%) from the corresponding transmission link and guides it to the photodetector. The photodetector converts the optical signal into an electrical signal and transmits it to the control and calibration module. The main optical path of the beam splitter continues to transmit most of the optical signal to the on-chip spectral analysis channel.

[0038] (vi) Control and Calibration Module The control and calibration module is connected to the optical switch module and the optical power monitoring module respectively. It is used to control the channel switching of the optical switch module and to perform closed-loop position calibration of the optical switch module according to the monitoring signal of the optical power monitoring module.

[0039] The control and calibration module receives channel selection commands from the central control and computing module and outputs the corresponding electrostatic drive voltage to the optical switch module. Simultaneously, it reads signals from the optical power monitoring modules of each channel to determine whether the microlens has accurately reached the target position. If the detected position deviation exceeds a threshold, the module automatically executes a fine-tuning calibration procedure, adjusting the drive voltage until the coupling efficiency returns to the preset range, and updates and stores the calibrated drive parameters.

[0040] Thus, this system consists of six major modules: an input coupling module, an optical switch module, N polarization-maintaining fiber transmission links, N output coupling modules, an optical power monitoring module, and a control and calibration module, forming a complete optical front-end preprocessing link.

[0041] II. Working Principle The core principle of this invention lies in using the channel allocation mechanism of the optical front end to physically reduce the dimension of the encoding and sampling process of the computational spectrometer, while ensuring the determinism and stability of the sampling matrix through end-to-end polarization-preserving transmission and closed-loop calibration.

[0042] The mathematical essence of a computational spectrometer is to encode and modulate the incident light using a series of filters with known spectral responses, and then record the encoded total light intensity value using a detector to establish a system of linear equations: ; in, For measurement vectors, For the sampling matrix, The vector to be reconstructed is shown. In wideband measurement scenarios, if a single filter channel is used to cover the entire band, the on-chip filter unit must be designed with a sufficiently large free spectral range to cover the wide spectral interval. This directly leads to a sharp decrease in the filter's quality factor, broadening of the resonance peak, and deterioration of the filter contrast. Mathematically, the sampling matrix... The spectral correlation between row vectors is enhanced, the matrix condition number deteriorates, the equation system tends to be ill-conditioned, and the error amplification effect of spectral reconstruction is significant.

[0043] This invention introduces an optical switch channel allocation mechanism at the optical front end, dividing the entire wavelength band into N sub-bands. Each sub-band corresponds to an independent detection channel and a corresponding on-chip spectral analysis channel. Driven by the control and calibration module, the optical switch module sequentially switches the input light to the output port corresponding to each channel. When the optical switch module switches to the i-th channel, the on-chip filtering unit within that channel performs fine filtering and modulation only on the spectral components within the allocated sub-band; components of other bands are naturally filtered out or attenuated to extremely low levels. Thus, the problem of reconstructing the entire wavelength spectrum is decomposed into N parallel sub-problems, each of which only needs to be solved within a narrower sub-band. The equivalent spectral bandwidth of each sub-channel is compressed to a fraction of the full wavelength. This allows the on-chip filtering unit within this channel to be designed with a free spectral range much smaller than the full-band bandwidth, thereby achieving a higher quality factor and a sharper resonant response within this sub-band. From a mathematical perspective, the dimensionality of the sampling matrix for each sub-channel is significantly reduced, the spectral orthogonality between row vectors is significantly improved, and the numerical stability of spectral reconstruction is enhanced.

[0044] In terms of the optical transmission link, this invention selects sulfide glass polarization-maintaining fiber or fluoride glass polarization-maintaining fiber as the transmission medium, which has excellent light transmission performance in the short-wave infrared band. The end-to-end polarization-maintaining design ensures that the polarization state defined at the input end of the optical switch module is transmitted to the input end of the on-chip spectral analysis channel without rotation, so that the sampling matrix degenerates into a deterministic matrix, eliminating the time-varying nature of the matrix introduced by random polarization changes, and ensuring the consistency of coded sampling and reconstruction accuracy.

[0045] In terms of optical switch control, this invention sets up an optical power monitoring module in each output channel to monitor the coupled optical power in real time. When the optical switch module switches to a certain channel, the control and calibration module compares the monitored value with the calibration reference value. If the deviation exceeds the preset tolerance, the drive voltage is automatically fine-tuned, and the optimal coupling position is found through gradient search, so that the coupling efficiency of that channel is restored to the calibration level. This closed-loop mechanism realizes the unified normalization of the optical power reference between channels, ensuring that the sampling data of N channels are under the same intensity reference, providing a physical consistency guarantee for subsequent spectral stitching. III. Specific Implementation Examples The implementation of the present invention will be described in detail below with reference to a specific embodiment. In this embodiment, the wavelength range of the broadband optical signal to be measured is 400nm~2500nm (covering the visible light to short-wave infrared band), and N is 8.

[0047] Example 1 This embodiment provides a method for allocating wideband optical switch channels for computational spectrometers, including the following steps.

[0048] Step 1: Band configuration.

[0049] Based on the wavelength range (400nm~2500nm) of the broadband optical signal under test, the entire band is divided into 8 sub-bands, each assigned to an independent detection channel. An exemplary division is as follows: Channel 1 covers 400nm~660nm, Channel 2 covers 660nm~920nm, Channel 3 covers 920nm~1180nm, Channel 4 covers 1180nm~1440nm, Channel 5 covers 1440nm~1700nm, Channel 6 covers 1700nm~1960nm, Channel 7 covers 1960nm~2220nm, and Channel 8 covers 2220nm~2500nm. An overlap region is reserved between each adjacent sub-band. For example, a 20nm overlap width is reserved between adjacent channels (e.g., the last 660nm of channel 1 coincides with the first 660nm of channel 2; in actual design, channel 1 can be set to cover 400nm~670nm, channel 2 to cover 650nm~920nm, and the overlap region is 650nm~670nm), for intensity matching calibration during subsequent spectral stitching. Each channel's on-chip spectral analysis channel contains a filter unit optimized for the corresponding sub-band, ensuring high resolution and high filtering contrast within each sub-band.

[0050] Step 2: Initialize calibration.

[0051] During initial power-on or recalibration, the control and calibration module drives the optical switch module to sequentially switch to each detection channel. Taking channel 1 as an example, the control and calibration module outputs the driving voltage corresponding to channel 1, and the microlens inside the optical switch module deflects to the corresponding angle, reflecting and coupling the input light to the output port of channel 1. At this time, the optical power monitoring module corresponding to channel 1 monitors the coupled optical power of the link in real time and transmits the monitoring value to the control and calibration module. The control and calibration module records the optical power reference value of channel 1. and the corresponding optimal driving voltage Repeat the same operation for channels 2 through 8, and record the optical power reference value for each channel. ~ and the corresponding optimal driving voltage ~ The aforementioned reference values ​​are stored in the non-volatile memory of the control and calibration module, serving as a reference for subsequent closed-loop calibration.

[0052] Step 3: Time-sharing sampling.

[0053] Following a preset channel switching sequence (e.g., 1→2→3→4→5→6→7→8→1→2→…), the control and calibration module controls the optical switch module to sequentially switch the input broadband optical signal to each detection channel. Taking switching to channel 1 as an example: the control and calibration module calls the optimal driving voltage for channel 1 stored in step 2. The signal is output to the optical switch module, where a microlens deflects the input broadband optical signal to the corresponding angle, reflecting and coupling it to the output port of channel 1. The optical signal is transmitted via the polarization-maintaining fiber optic link corresponding to channel 1, and after coupling by the output coupling module, it is output to the on-chip spectral analysis channel corresponding to channel 1. The filtering unit within this channel encodes and samples the allocated sub-band (400nm~660nm). After sampling of channel 1 is completed, the control and calibration module drives the optical switch module to switch to the next channel according to the switching sequence, completing sampling for all channels sequentially. The total time required for each channel to complete one full sampling depends on the switching settling time of the optical switch module and the integration time of the detectors in each channel. In this embodiment, the switching settling time of the optical switch module is less than 10ms.

[0054] Step 4: Real-time calibration.

[0055] After each switch to the target detection channel, the control and calibration module immediately performs real-time calibration. Taking switching to channel 1 as an example: after the optical switch module switches to channel 1, the control and calibration module reads the monitoring value from the optical power monitoring module of channel 1. The monitored value is compared with the optical power reference value of channel 1 recorded in step 2. A comparison is performed. If the deviation exceeds the preset tolerance range (e.g., ±5% of the reference value), a fine-tuning calibration procedure is initiated. Fine-tuning calibration employs a gradient search method: the control and calibration module gradually adjusts the driving voltage along the upward direction of the optical power gradient (e.g., increasing or decreasing in 0.01V steps), while simultaneously reading the optical power monitoring value in real time, until the coupled optical power recovers to the optical power reference value range. After calibration, the updated driving voltage is stored as the driving parameter for the next switch to this channel. If the deviation is within the preset tolerance range, no calibration is required, and the system directly enters the sampling state.

[0056] Step 5: Dynamic reconfiguration (optional).

[0057] Based on actual measurement needs, the control and calibration module can dynamically adjust the channel switching sequence and / or the dwell time of each channel. For example, if fine measurements are required for the sub-band (920nm~1180nm) corresponding to channel 3, the sampling frequency of channel 3 can be increased from once to three times, or the dwell time of channel 3 in the switching sequence can be increased. Furthermore, if a sub-band has no characteristic signal, sampling of that channel can be skipped to shorten the total measurement time.

[0058] The sampled data from each channel is independently reconstructed by the data processing module of the subsequent computational spectrometer to obtain the reconstructed spectrum of each sub-band. Since an overlap region is reserved between adjacent sub-bands, the data processing module uses the spectral intensity information within the overlap region to perform intensity matching and smooth stitching of the reconstructed spectra of adjacent channels, eliminating spectral discontinuities introduced by channel differences, and finally outputting a continuous reconstructed spectrum across the entire wavelength range (400nm~2500nm). It should be noted that the specific algorithms for spectral reconstruction and stitching fall within the existing technical scope of computational spectrometer back-end processing, and this invention does not limit them.

[0059] Example 2 The difference between this embodiment and Embodiment 1 lies in the value of N and the band division method. In this embodiment, the wavelength range of the broadband optical signal under test is 900nm~1700nm (near-infrared band), and N is 4. The entire band is divided into 4 sub-bands: channel 1 covers 900nm~1100nm, channel 2 covers 1080nm~1280nm, channel 3 covers 1260nm~1460nm, and channel 4 covers 1440nm~1700nm, with a 20nm overlap area reserved between adjacent channels. The remaining workflow (initialization calibration, time-division sampling, real-time calibration, dynamic reconfiguration) is the same as in Embodiment 1, and will not be repeated here.

[0060] Example 3 The difference between this embodiment and Embodiment 1 lies in the specific material selection for the polarization-maintaining fiber transmission link. For applications covering the short-wave infrared (e.g., wavelengths greater than 2000nm), sulfide glass polarization-maintaining fiber is preferred for the polarization-maintaining fiber transmission link; for applications primarily operating in the near-infrared (e.g., 900nm~1700nm), fluoride glass polarization-maintaining fiber is preferred. Both materials exhibit low transmission loss and high polarization extinction ratio within their respective applicable wavelength bands. The remaining structure and workflow are the same as in Embodiment 1.

[0061] By employing a front-end preprocessing system comprised of an input coupling module, an optical switch module, N polarization-maintaining fiber transmission links, N output coupling modules, an optical power monitoring module, and a control and calibration module, and combining the aforementioned time-division switching and closed-loop calibration workflow, this invention achieves intelligent dimensionality reduction allocation of a wide-band spectrum at the optical front end. This effectively resolves the physical contradiction between wide-band coverage and high spectral resolution. Simultaneously, the end-to-end polarization-maintaining transmission and closed-loop calibration mechanism ensures the long-term stability and measurement repeatability of the system, providing a reliable optical front-end solution for wide-band high-precision applications of computational spectrometers.

[0062] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A broadband optical switch channel allocation system for computational spectrometers, characterized in that, include: The input coupling module is used to receive the broadband optical signal under test and couple it into the polarization-maintaining fiber; An optical switch module has one common input port and N output ports, used to time-division switch the broadband optical signal under test input via the input coupling module to any of the N output ports for output, where N is an integer greater than or equal to 2; the optical switch module includes a microlens and an input collimator and N output collimators respectively disposed on the incident optical path side and the outgoing optical path side of the microlens; N independent polarization-maintaining fiber transmission links, one end of each polarization-maintaining fiber transmission link is connected to one output port of the optical switch module, used to transmit the optical signal output by the optical switch module with polarization maintenance. N output coupling modules, each of which is located at the other end of a polarization-maintaining fiber transmission link, are used to couple the optical signal output from the polarization-maintaining fiber transmission link to an on-chip spectral analysis channel of a computational spectrometer. An optical power monitoring module is installed on each of the polarization-maintaining optical fiber transmission links to monitor the coupled optical power of the corresponding transmission link in real time. The control and calibration module is connected to the optical switch module and the optical power monitoring module respectively, and is used to control the channel switching of the optical switch module and perform closed-loop position calibration of the optical switch module according to the monitoring signal of the optical power monitoring module.

2. The broadband optical switch channel allocation system for computational spectrometers according to claim 1, characterized in that, The optical switch module is a 1×N type optical switch based on microelectromechanical systems, which achieves the switching of the input light spot between different output ports by electrically driving the two-dimensional angular deflection of the microlens.

3. The broadband optical switch channel allocation system for computational spectrometers according to claim 1, characterized in that, The polarization-maintaining fiber transmission link uses sulfide glass polarization-maintaining fiber or fluoride glass polarization-maintaining fiber.

4. The broadband optical switch channel allocation system for computational spectrometers according to claim 1, characterized in that, The input fiber of the input coupling module is a polarization-maintaining fiber, and its slow axis is aligned with the slow axis of the polarization-maintaining pigtail at the input end of the optical switch module.

5. The broadband optical switch channel allocation system for computational spectrometers according to claim 1, characterized in that, Polarization compensation elements are respectively provided in the optical paths between the input collimator and the microlens, and between the microlens and each of the output collimators.

6. The broadband optical switch channel allocation system for computational spectrometers according to claim 1, characterized in that, Each of the on-chip spectral analysis channels includes a filter unit optimized for the corresponding sub-band.

7. The broadband optical switch channel allocation system for computational spectrometers according to claim 1, characterized in that, Each polarization-maintaining fiber transmission link has an optical power monitoring module located at one end near the optical switch module. The optical power monitoring module includes a beam splitter and a photodetector. The beam splitter is used to separate a portion of the optical signal in the corresponding transmission link and guide it to the photodetector.

8. A method for allocating broadband optical switch channels for computational spectrometers, characterized in that, Includes the following steps: Step 1: Based on the wavelength range of the broadband optical signal to be tested, divide the entire band into N sub-bands, and assign each sub-band to an independent detection channel, where N is an integer greater than or equal to 2; Step 2: Drive the optical switch module to switch to each detection channel in sequence, and record the optical power reference value and the corresponding driving voltage of each detection channel; Step 3: According to the preset channel switching sequence, control the optical switch module to switch the input broadband optical signal to each detection channel in sequence. After transmission through the polarization-maintaining fiber transmission link and coupling through the output coupling module of each detection channel, the signal is output to the corresponding on-chip spectral analysis channel. Step 4: After each switch to the target detection channel, monitor the coupled optical power of the detection channel in real time, compare the monitored value with the optical power reference value of the detection channel recorded in Step 2, and if the deviation exceeds the preset tolerance range, automatically adjust the driving voltage of the optical switch module until the monitored value returns to the optical power reference value range.

9. The method for allocating broadband optical switch channels for computational spectrometers according to claim 8, characterized in that, In step 1, an overlap area is reserved between each adjacent sub-band.

10. The method for allocating wideband optical switch channels for computational spectrometers according to claim 8, characterized in that, In step 4, the automatic adjustment of the driving voltage of the optical switch module adopts a gradient search method, gradually adjusting the driving voltage along the upward direction of the optical power gradient until the coupled optical power is restored to the optical power reference value range.

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