Miniature optical fiber scattering spectrometer and wavelength analysis method thereof
Through the micro-fiber scattering spectrometer combined with the spectral reconstruction algorithm, the size and resolution, loss, disturbance and integration problems of the spectral instrument are solved, and efficient miniaturized spectral measurement is achieved.
Patent Information
- Application Number
- CN202510494613.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-08-08
AI Technical Summary
Existing spectral instruments have problems such as large device size, low spectral resolution, high insertion loss, weak disturbance resistance and low integration, especially in the fields of portability and high precision.
A micro fiber scattering spectrometer is used, combining single-mode fiber and coreless fiber, and multi-layer random scattering points are installed inside. The laser beam is transmitted through the fiber and speckle images are formed on the charge-coupled device. High-resolution analysis is performed by combining the spectral reconstruction algorithm.
It realizes the improvement of spectral resolution while maintaining miniaturization, reducing insertion loss, enhancing disturbance resistance, improving integration, and meeting the high-efficiency spectral measurement needs of portable devices.
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Figure CN120445408A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the fields of spectral analysis and optical instruments, and in particular to a miniature optical fiber scattering spectrometer and a wavelength analysis method thereof. Background Art
[0002] Spectroscopic analysis, as an important analytical tool, is widely used in fields such as chemistry, biology, and environmental monitoring. However, traditional spectrometers have numerous limitations, such as large device size, low spectral resolution, high insertion loss, weak anti-disturbance capabilities, and low integration. These drawbacks severely restrict their practical effectiveness in specific application scenarios, especially in areas requiring portability and high precision.
[0003] In recent years, the development of micro-spectrometers has alleviated the above problems to a certain extent, but still faces the following technical challenges:
[0004] The contradiction between device miniaturization and high resolution: Current technology makes it difficult to maintain high spectral resolution while reducing the size of the spectrometer, which limits its application potential in the field of high-precision measurement.
[0005] Weak insertion loss and anti-disturbance capabilities: Micro-spectrometers often introduce large insertion loss during the system integration process and are easily disturbed by the external environment, affecting the accuracy and reliability of the measurement results.
[0006] Insufficient integration: The integration of existing micro-spectrometers still needs to be improved, and it is difficult to meet the urgent demand for high integration in portable devices and real-time monitoring systems. Summary of the Invention
[0007] The purpose of this application is to provide a miniature optical fiber scattering spectrometer and a wavelength analysis method thereof to solve the contradiction between device miniaturization and high resolution, weak insertion loss and anti-disturbance capability, and insufficient integration.
[0008] To achieve the above objectives, this application provides the following solutions:
[0009] In a first aspect, the present application provides a miniature fiber optic scattering spectrometer, comprising: a fiber optic structure and a charge coupled device connected to an output end of the fiber optic structure;
[0010] The optical fiber structure includes a single-mode optical fiber and a coreless optical fiber connected in sequence; a writing area is provided inside the coreless optical fiber; and the writing area is inscribed with multiple layers of random scattering points;
[0011] When the incident light passes through the single-mode optical fiber and is incident on the multi-layer random scattering points, the laser beam is scattered multiple times in the scattering medium and forms a wavelength-related speckle image on the charge coupled device.
[0012] In a second aspect, the present application provides a wavelength analysis method based on a micro-fiber scattering spectrometer, comprising:
[0013] Based on the above-mentioned micro-fiber scattering spectrometer, laser beams of different wavelengths are input to the input end of a single-mode optical fiber, and the laser beams are scattered by a coreless optical fiber. The charge-coupled device collects a wavelength-dependent speckle image; a writing area is provided inside the coreless optical fiber; the writing area is inscribed with multiple layers of random scattering points;
[0014] Processing the speckle image based on a spectral reconstruction algorithm to determine spectral distribution information; the spectral distribution information is the correspondence between wavelength and speckle image;
[0015] Analyze different wavelengths according to the spectral distribution information to obtain wavelength analysis results;
[0016] The optimal resolution of the micro-fiber scattering spectrometer is determined according to the wavelength analysis result.
[0017] According to the specific embodiments provided in this application, this application discloses the following technical effects:
[0018] This application combines optical fiber with scattering effects, and writes multiple layers of random scattering points in coreless optical fiber as a splitting element. By using optical fiber as the transmission medium, it has extremely low insertion loss and good stability, enhances the anti-disturbance ability of the micro-spectrometer in different environments, ensures the reliability of the measurement results, thereby significantly improving the optical information capacity and reducing the size of the instrument; when the incident light beam passes through the scattering medium, a randomly distributed speckle image is formed. The micro-fiber scattering spectrometer uses optical fiber transmission and core optical elements, making it light in weight, easy to use and highly integrated. The micro-fiber scattering spectrometer has a compact structure and is easy to couple and integrate with other devices, meeting the needs of practical applications for high integration, improving the efficiency and flexibility of the overall system, and can be easily connected to the laser to be measured at a low cost, which is expected to improve automation performance.
[0019] In addition, the present application also provides a wavelength analysis method based on a micro-fiber scattering spectrometer, which uses a spectral reconstruction algorithm to denoise the speckle image, determine the spectral distribution information, analyze different wavelengths, obtain wavelength analysis results, and determine the optimal resolution of the micro-fiber scattering spectrometer. Combined with advanced spectral reconstruction algorithms, it is possible to achieve high-resolution spectral measurement while maintaining the miniaturization of the micro-fiber scattering spectrometer.
[0020] This application opens up a new direction for the development of dedicated spectrometers, demonstrates broad scientific research significance and application potential, and can be effectively used for the detection of different substances. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0022] Figure 1 A structural diagram of a micro-fiber scattering spectrometer provided in one embodiment of the present application;
[0023] Figure 2 A schematic diagram of a single layer of random scattering points in a coreless optical fiber according to an embodiment of the present application;
[0024] Figure 3 This is a schematic diagram of the speckle images corresponding to different reference wavelengths and the comparison between the reconstructed wavelength and the reference wavelength provided in an embodiment of the present application; wherein, Figure 3 (a) is a schematic diagram of the speckle image corresponding to the reference wavelength λ1; Figure 3 (b) is a schematic diagram of the speckle image corresponding to the reference wavelength λ2; Figure 3 (c) is the reconstruction wavelength λ measured and reference wavelength λ reference Schematic diagram of the comparison;
[0025] Figure 4 A schematic diagram of a wavelength analysis method based on a micro-fiber scattering spectrometer provided in one embodiment of the present application;
[0026] Figure 5 A schematic diagram of the comparison between the measurement wavelength and the reference wavelength, the resolution of the reconstructed wavelength, and the error analysis provided in one embodiment of the present application. DETAILED DESCRIPTION
[0027] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0029] like Figure 1As shown, the present application provides a miniature fiber scattering spectrometer, comprising: a fiber structure and a charge coupled device (CCD) 1 connected to the output end of the fiber structure; the fiber structure comprises a single-mode fiber 2 and a coreless fiber 3 connected in sequence; a writing area is provided inside the coreless fiber 3; the writing area is inscribed with multiple layers of random scattering points 4, such as Figure 2 As shown; when the incident light passes through the single-mode optical fiber 2 and is incident on the multi-layer random scattering points 4, the laser beam is scattered multiple times in the scattering medium and forms a wavelength-related speckle image on the CCD1.
[0030] In an exemplary embodiment, the single-mode optical fiber 2 and the coreless optical fiber 3 are welded, and during the welding process, a fiber fusion splicer is used to optimize the contact surface between the single-mode optical fiber 2 and the coreless optical fiber 3 .
[0031] Furthermore, the single-mode optical fiber 2 and the coreless optical fiber 3 are welded and placed on a three-dimensional displacement platform. The platform moves precisely at a specific speed under the control of computer software to ensure high-precision positioning of the optical fiber.
[0032] In an exemplary embodiment, the multi-layer random scattering dots 4 are formed by exposing the single-mode optical fiber 2 point by point using a femtosecond laser beam focused by a femtosecond laser.
[0033] Furthermore, inside the coreless optical fiber 3, a focused femtosecond laser beam is used to expose points along the optical fiber, and the refractive index of the exposed area inside the optical fiber increases, forming randomly distributed scattering points 4.
[0034] Due to the cylindrical structure of the optical fiber, refraction and secondary focusing may occur during the writing process, resulting in an elongated focused spot, which affects the writing quality. To improve the focus performance and obtain a smaller spot size, a refractive index matching fluid is added to the writing area to ensure that the laser beam can be accurately focused to a single point on the optical fiber core.
[0035] In an exemplary embodiment, the operating parameters of the femtosecond laser include pulse duration, single pulse energy, pulse frequency, and scanning speed.
[0036] The present application ensures the quality and randomness of the scattering point 4 by precisely adjusting the pulse energy, pulse frequency and scanning speed, thereby optimizing the performance of the spectrometer.
[0037] In an exemplary embodiment, the writing area of the coreless optical fiber 3 has a refractive index reflecting liquid.
[0038] In an exemplary embodiment, the coreless optical fiber 3 has a diameter of 125 μm and an effective length of 1 mm.
[0039] In an exemplary embodiment, 30 layers of writing areas are set along the axial direction of the coreless optical fiber 3; 100 random scattering points 4 are evenly distributed in each layer of writing area; the spacing between adjacent layers is 5 μm; and the spacing between adjacent random scattering points 4 in the same layer is greater than 2 μm.
[0040] Furthermore, after the writing is completed, light beams of different wavelengths are input to the incident end of the single-mode optical fiber 2. The random scattering points 4 written by femtoseconds have specific responses to different wavelengths, thereby generating different speckle images, such as Figure 3 shown.
[0041] These speckle images are collected using CCD1, and combined with the singular value decomposition method in the spectral reconstruction algorithm to remove the noise effect and obtain spectral distribution information, that is, the correspondence between wavelength and speckle image, thereby achieving high-resolution wavelength analysis.
[0042] Compared with the existing technology, this application has the following advantages:
[0043] 1. Balancing Miniaturization and High Resolution: This application utilizes a multilayer of random scattering points (4) inscribed by a femtosecond laser as a spectroscopic element, combined with advanced spectral reconstruction algorithms, to achieve high-resolution spectral measurements while maintaining the spectrometer's miniaturization. This design overcomes the traditional technical bottleneck between miniaturization and high resolution, enabling the spectrometer to effectively function in applications requiring high precision.
[0044] 2. Reduce insertion loss and improve anti-disturbance: This application uses optical fiber as the transmission medium, which has extremely low insertion loss and good stability, enhances the anti-disturbance ability of the micro-spectrometer in different environments, and ensures the reliability of the measurement results.
[0045] 3. Achieve high degree of integration: The micro-fiber scattering spectrometer has a compact structure and is easy to couple and integrate with other devices, meeting the demand for high integration in practical applications and improving the efficiency and flexibility of the overall system.
[0046] Overall, compared to traditional spectrometers, this miniature fiber optic scattering spectrometer offers higher resolution, miniaturization, portability, and improved noise immunity, along with significantly increased integration. It opens new possibilities for spectral measurement and sensing applications, and can be widely used in a variety of fields, including chemical composition analysis, material characterization, and environmental monitoring.
[0047] The embodiment of the present application also provides a wavelength analysis method based on a micro-fiber scattering spectrometer, which is executed by a computer device, specifically, it can be executed by a computer device such as a terminal or a server alone, or it can be executed by a terminal and a server together. In the embodiment of the present application, Figure 4 As shown, the method includes the following steps.
[0048] S1: Based on the above-mentioned micro-fiber scattering spectrometer, laser beams of different wavelengths are input to the input end of the single-mode optical fiber 2, and the laser beams are scattered by the coreless optical fiber 3. The CCD1 collects the wavelength-related speckle image; the coreless optical fiber 3 is provided with an inscription area inside; the inscription area is inscribed with multiple layers of random scattering points 4.
[0049] S2: Processing the speckle image based on a spectral reconstruction algorithm to determine spectral distribution information; the spectral distribution information is the correspondence between wavelength and speckle image.
[0050] S3: Analyze different wavelengths according to the spectral distribution information to obtain wavelength analysis results.
[0051] S4: Determine the optimal resolution of the micro-fiber scattering spectrometer according to the wavelength analysis result.
[0052] In an exemplary embodiment, S2 may be replaced by the following steps.
[0053] The speckle image is denoised using a singular value decomposition method in the spectral reconstruction algorithm to determine spectral distribution information.
[0054] Furthermore, considering the transmission process of light waves in the spectrum measurement system as a whole, the light intensity distribution I(r,λ) received by the observation screen detector can be expressed as:
[0055] I(r,λ)=∫S(λ)K(r,λ)dλ
[0056] Where S(λ) represents the spectral flux density of the input light, and K(r,λ) represents the discretization matrix.
[0057] The spectral transfer matrix is also discretized. When a tunable light source is used to scan light waves within a specific wavelength range, the spectrum is discretized by setting the scanning range and step size to obtain a data cube. In addition, the output light field captured by the detector is also a discrete value. By selecting a suitable area, the output light field can also be discretized. Therefore, it is adopted. After completing the calibration of the spectral transfer matrix K, the speckle pattern I corresponding to the light to be measured is obtained, and the inverse matrix K of the spectral transfer matrix is solved. -1 , we can get: S = K -1 I. However, due to various factors such as stray light, experimental environment disturbance, and system mechanical stability, this project intends to use singular value decomposition (SVD) to solve the spectrum. For the spectral transmission matrix K, K T The non-negative square roots of the eigenvalues of K are called the singular values of K. If it is an n-order square matrix, it is recorded as the set of all singular values of K.
[0058] In an exemplary embodiment, S4 may be replaced by the following steps.
[0059] Based on the wavelength analysis results, a wavelength data cube is constructed and the system spectral transmission matrix is calibrated.
[0060] Furthermore, in the algorithmic process from speckle pattern to spectrum, there is always a set of unconfused spectra that can be distinguished, which can be given by the singular value calibration matrix decomposition: K = UDV T .
[0061] Any spectrum can be decomposed into a linear combination of standard orthogonal (independent) spectrum sets, Vi. Any speckle pattern can be decomposed into a linear combination of standard orthogonal patterns, Ui. D is a diagonal matrix with a scaling factor σ i , representing the brightness of the pattern produced by each spectrum. K is the speckle pattern calibration matrix for each wavelength. Using this algorithm, the only speckle image was reconstructed. The resulting relationship between the measured wavelength and the corrected wavelength laid the foundation for subsequent optimization calculations.
[0062] The optimal resolution of the micro-fiber scattering spectrometer is determined according to the wavelength data cube and the system spectral transmission matrix.
[0063] During the experiment, the laser was operated in the range of 1100-1150 nm, and the 90 wavelengths of 1107-1116 nm were reconstructed by the above wavelength analysis method with a step size of 0.1 nm. Finally, the spectrometer achieved a resolution of 0.327 nm. Figure 5 shown.
[0064] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0065] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.
Claims
1. A miniature optical fiber scattering spectrometer, characterized in that: The micro-fiber scattering spectrometer comprises: an optical fiber structure and a charge coupled device connected to the output end of the optical fiber structure; The optical fiber structure includes a single-mode optical fiber and a coreless optical fiber connected in sequence; a writing area is provided inside the coreless optical fiber; and the writing area is inscribed with multiple layers of random scattering points; When the incident light passes through the single-mode optical fiber and is incident on the multi-layer random scattering points, the laser beam is scattered multiple times in the scattering medium and forms a wavelength-related speckle image on the charge coupled device.
2. The micro fiber scattering spectrometer according to claim 1, characterized in that: The single-mode optical fiber is welded to the coreless optical fiber, and during the welding process, a fiber fusion splicer is used to optimize the contact surface between the single-mode optical fiber and the coreless optical fiber.
3. The micro fiber optic scattering spectrometer according to claim 1, characterized in that: The multi-layer random scattering points are formed by exposing the femtosecond laser beam focused by a femtosecond laser point by point along the single-mode optical fiber.
4. The micro fiber scattering spectrometer according to claim 3, characterized in that: The working parameters of the femtosecond laser include pulse duration, single pulse energy, pulse frequency and scanning speed.
5. The micro fiber scattering spectrometer according to claim 3, characterized in that: The writing area of the coreless optical fiber is provided with a refractive index reflecting liquid.
6. The micro fiber optic scattering spectrometer according to claim 1, characterized in that: The coreless optical fiber has a diameter of 125 μm and an effective length of 1 mm.
7. The micro fiber scattering spectrometer according to claim 1, characterized in that: 30 layers of writing areas are set along the axial direction of the coreless optical fiber; 100 random scattering points are evenly distributed in each layer of writing area; The distance between adjacent layers is 5μm; the distance between adjacent scattering points in the same layer is greater than 2μm.
8. A wavelength analysis method based on a micro-fiber scattering spectrometer, characterized in that: include: A miniature fiber scattering spectrometer according to any one of claims 1 to 7, wherein laser beams of different wavelengths are input to the input end of a single-mode optical fiber, and the laser beams are scattered by a coreless optical fiber, and a wavelength-dependent speckle image is collected by the charge-coupled device; a writing area is provided inside the coreless optical fiber; and the writing area is inscribed with multiple layers of random scattering points; Processing the speckle image based on a spectral reconstruction algorithm to determine spectral distribution information; the spectral distribution information is the correspondence between wavelength and speckle image; Analyze different wavelengths according to the spectral distribution information to obtain wavelength analysis results; The optimal resolution of the micro-fiber scattering spectrometer is determined according to the wavelength analysis result.
9. The wavelength analysis method based on the micro-fiber scattering spectrometer according to claim 8, characterized in that: The speckle image is processed based on a spectral reconstruction algorithm to determine spectral distribution information, specifically including: The speckle image is denoised using a singular value decomposition method in the spectral reconstruction algorithm to determine spectral distribution information.
10. The wavelength analysis method based on a micro-fiber scattering spectrometer according to claim 8, characterized in that: Determining the optimal resolution of the micro-fiber scattering spectrometer based on the wavelength analysis results specifically includes: Based on the wavelength analysis results, a wavelength data cube is constructed and a system spectral transmission matrix is calibrated; The optimal resolution of the micro-fiber scattering spectrometer is determined according to the wavelength data cube and the system spectral transmission matrix.