Sweep-frequency light interference distance measurement reference real-time correction system, method, program, equipment and storage medium

Abstract

The invention belongs to the technical field of laser interference measurement optical fiber sensing, and particularly relates to a system, a method, a program, equipment and a storage medium for real-time correction of a sweep frequency light interference distance measurement reference. Firstly, the arm length difference of the interferometer to be measured is calibrated, and then according to the output of the interferometer to be measured and an optical signal reflected back to the circulator by a first target object, the calibrated arm length difference of the interferometer to be measured is adopted as a correction parameter to obtain a stepping distance measurement value; according to the environment temperature measured by the temperature sensor in real time, the optical path difference of the interferometer to be measured is calculated, and the sweep frequency light interference distance measurement reference is corrected in real time. By introducing a dynamic calibration scheme, a temperature compensation technology and precise displacement feedback, the defects of a traditional calibration method are overcome, real-time and accurate auxiliary interferometer arm length difference dynamic calibration is achieved, a reliable correction basis and higher measurement precision are provided for a sweep frequency light interference distance measurement system, and the method is suitable for large-scale popularization and application. And the application requirement of high-precision distance measurement in a complex environment is met.

Description

Technical Field

[0001] This invention belongs to the field of laser interferometry fiber optic sensing technology, specifically relating to a real-time correction system, method, program, equipment, and storage medium for a swept-frequency optical interferometric ranging measurement reference. Background Technology

[0002] Frequency scanning interferometry (FSI) is widely used in manufacturing and processing due to its high resolution, long ranging range, and blind-zone-free characteristics. However, traditional reference calibration methods usually rely on long-stroke displacement stages and static environments, which have shortcomings such as large mechanical backlash errors, lag in temperature drift compensation, and untimely calibration in dynamic environments, making it difficult to meet the requirements of sub-micron or even nanometer-level measurement accuracy.

[0003] In existing technologies, traditional methods for interferometer arm length difference correction mainly include white light interferometry, optical time-domain reflectometry, and methods based on gas absorption cells and grating beat frequency signals. Reference [CN202410612459] proposes using a gas absorption cell combined with grating beat frequency signals for reference optical path calibration to improve calibration accuracy; however, this method relies on indirect tracing and is easily affected by interference in complex environments. Reference [CN202410982189] discusses the limitations of white light interferometry and time-domain reflectometry in fiber optic interferometer arm length difference measurement, including limited scanning bandwidth, large data volume, and low response speed. It proposes using optical frequency-domain reflectometry and introducing an auxiliary interferometer to improve measurement accuracy and speed, but it does not adequately consider dynamic environmental changes and temperature compensation. Reference [CN201910829678] solves the problems of large scanning bandwidth and large data volume in traditional methods through a signal splicing method based on a gas absorption cell; however, its overall measurement still remains at the static calibration stage and cannot cope with nonlinear errors caused by real-time environmental changes. Summary of the Invention

[0004] The purpose of this invention is to provide a real-time correction system, method, program, device, and storage medium for a swept-frequency optical interferometric ranging measurement reference.

[0005] A real-time correction system for a sweeping optical interferometric ranging measurement reference includes a light source module, a temperature sensor, a circulator, a fiber optic microprobe with a reference surface, a short-stroke displacement stage module, and a reference laser interferometer.

[0006] The short-stroke displacement stage module includes a first target object, a second target object, a fixed support, and a displacement stage; the displacement stage is used to control the first target object and the second target object to move linearly along the fixed support.

[0007] The light signal output by the light source module is divided into two paths. One path is input to the interferometer under test through the optical isolator, and the other path is transmitted to the first target object after passing through the circulator and the fiber optic micro probe with the reference surface. The first target object reflects the light signal back to the circulator.

[0008] The optical signal output by the reference laser interferometer is transmitted to the second target object after passing through the fiber optic microprobe, and the second target object reflects the optical signal back to the reference laser interferometer.

[0009] Furthermore, it also includes a signal acquisition module, used to acquire the output of the interferometer under test, the optical signal reflected back to the circulator from the first target object, the output of the reference laser interferometer, and the ambient temperature measured in real time by the temperature sensor.

[0010] Furthermore, the light source module includes an input light source, a second optical isolator, and a coupler; the optical signal generated by the input light source is protected for unidirectional transmission by the second optical isolator and then injected into the optical fiber coupler; the optical fiber coupler splits the optical signal into two paths.

[0011] Furthermore, the coupler, optical isolator, circulator, and fiber optic microprobe all employ single-mode fiber optic devices.

[0012] A method for real-time correction of a sweeping optical interferometric ranging reference includes the following steps:

[0013] Step 1: Measure the initial ambient temperature using a temperature sensor. Calibrate the arm length difference of the interferometer under test ;

[0014] Step 2: According to the task requirements, drive target object 1 and target object 2 to move linearly along the fixed support using a displacement stage; based on the output of the interferometer under test and the light signal reflected back to the circulator by target object 1, use the difference in calibration arm length of the interferometer under test. As a calibration parameter, obtain the step distance measurement value. ;

[0015] Based on the ambient temperature measured in real time by the temperature sensor Calculate the optical path difference of the interferometer under test. ;

[0016]

[0017] in, For the refractive index function of optical fiber, Wavelength; is the temperature coefficient of refractive index.

[0018] Furthermore, in the aforementioned step, the arm length difference of the interferometer under test is calibrated. Specifically, it includes the following steps:

[0019] Step 1.1: Obtain the arm length difference of the interferometer under test without correction. The displacement stage moves in preset steps. Drive target object 1 and target object 2 to move in a straight line along the fixed support;

[0020] The step distance measurement value is determined based on the output of the interferometer under test and the light signal reflected back to the circulator from the first target object. Determine the reference value for the step distance based on the output of the reference laser interferometer. ;

[0021] Step 1.2: Based on the preset step size With step distance measurement value Calculate the proportionality coefficient of the displacement response ;

[0022]

[0023] Based on the displacement response proportionality coefficient The arm length difference of the interferometer under test is corrected to obtain the preliminary corrected arm length difference of the interferometer under test. ;

[0024]

[0025] Step 1.3: Use the arm length difference of the interferometer under test after preliminary correction. As a new correction parameter, the output of the interferometer under test and the optical signal reflected back to the circulator from the first target object are demodulated a second time to obtain the updated step distance measurement value. ;

[0026] Step 1.4: Based on the updated step distance measurement values Reference value for step distance Calculate the final scaling factor ;

[0027]

[0028] According to the final proportional coefficient The arm length difference of the interferometer under test after preliminary correction Further corrections yielded the difference in calibration arm length of the interferometer under test. ;

[0029]

[0030] Furthermore, the arm length difference of the calibrated interferometer under test At that time, the initial ambient temperature The temperature is 23℃ ± 0.5℃.

[0031] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-described real-time correction method for the sweep frequency optical interferometric ranging measurement reference.

[0032] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described real-time correction method for the sweep frequency optical interferometric ranging measurement reference.

[0033] A computer program product includes computer instructions that, when executed by a processor, implement the steps of the above-described real-time correction method for the sweep frequency optical interferometric ranging measurement reference.

[0034] The beneficial effects of this invention are as follows:

[0035] This invention, by introducing a dynamic calibration scheme, temperature compensation technology, and precise displacement feedback, not only solves the shortcomings of traditional calibration methods, but also realizes real-time and accurate dynamic calibration of the auxiliary interferometer arm length difference. It provides a reliable calibration basis and higher measurement accuracy for the sweep frequency optical interferometric ranging system, meeting the application requirements of high-precision distance measurement in complex environments. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the real-time correction system for the sweep frequency optical interferometric ranging measurement reference in this invention.

[0037] Figure 2 Temperature coefficient of refractive index Scatter plot of temperature.

[0038] Figure 3 This is a diagram showing the real-time correction result of the measurement reference through temperature compensation in an embodiment of the present invention. Detailed Implementation

[0039] The present invention will now be further described with reference to the accompanying drawings.

[0040] This invention provides a real-time correction system for a sweep frequency optical interferometric ranging measurement reference, comprising a light source module 1, a temperature sensor 23, a circulator 31, a fiber optic microprobe with a reference surface 32, a short-stroke displacement stage module 4, a signal acquisition module 5, and a reference laser interferometer 62;

[0041] The short-stroke displacement stage module 4 includes a first target object 41, a second target object 42, a fixed support 43, and a displacement stage 44; the displacement stage 44 is used to control the first target object 41 and the second target object 42 to move linearly along the fixed support 43.

[0042] The light signal output by the light source module 1 is divided into two paths. One path passes through the optical isolator 21 and is input to the interferometer under test 22. The other path passes through the circulator 31 and the fiber optic micro probe 32 with the reference surface and is transmitted to the first target object 41. The first target object 41 reflects the light signal back to the circulator 31.

[0043] The optical signal output by the reference laser interferometer 62 is transmitted to the second target object 42 after passing through the fiber optic microprobe 61. The second target object 42 reflects the optical signal back to the reference laser interferometer 62.

[0044] It also includes a signal acquisition module 5, which is used to acquire the output of the interferometer under test 22, the light signal reflected back to the circulator 31 by the first target object 41, the output of the reference laser interferometer 62, and the ambient temperature measured in real time by the temperature sensor 23.

[0045] A real-time calibration method for a sweeping optical interferometric ranging measurement reference includes the following steps:

[0046] Step 1: Calibrate the arm length difference of the interferometer under test 22 ;

[0047] Step 1.1: Obtain the arm length difference of the interferometer 22 under test without correction. The displacement stage 44 moves in preset steps. Drive target 41 and target 42 to move in a straight line along the fixed support 43;

[0048] The step distance measurement value is determined based on the output of the interferometer 22 and the light signal reflected back to the circulator 31 from the first target object 41. Based on the output of the reference laser interferometer 62, determine the reference value for the step distance. The ambient temperature is measured by temperature sensor 23. ;

[0049] Step 1.2: Based on the preset step size With step distance measurement value Calculate the proportionality coefficient of the displacement response ;

[0050]

[0051] Based on the displacement response proportionality coefficient The arm length difference of the interferometer under test 22 is corrected to obtain the preliminary corrected arm length difference of the interferometer under test 22. ;

[0052]

[0053] Step 1.3: Using the arm length difference of the interferometer 22 under test after preliminary correction As a new correction parameter, the output of the interferometer 22 under test and the optical signal reflected back to the circulator 31 from the first target object 41 are demodulated a second time to obtain the updated step distance measurement value. This further eliminates nonlinear errors;

[0054] Step 1.4: Based on the updated step distance measurement values Reference value for step distance Calculate the final scaling factor ;

[0055]

[0056] According to the final proportional coefficient The arm length difference of the interferometer 22 under test after preliminary correction After further correction, the difference in the calibration arm length of the interferometer under test 22 was obtained. ;

[0057]

[0058] Step 2: According to the task requirements, drive target object 41 and target object 42 to move linearly along the fixed support 43 using the displacement stage 44; based on the output of the interferometer under test 22 and the light signal reflected back to the circulator 31 by target object 41, use the difference in calibration arm length of the interferometer under test 22. As a calibration parameter, obtain the step distance measurement value. ;

[0059] Based on the ambient temperature measured in real time by temperature sensor 23 Calculate the optical path difference of the interferometer 22 under test. ;

[0060]

[0061] in, For the refractive index function of optical fiber, Wavelength; is the temperature coefficient of refractive index.

[0062] Example 1:

[0063] like Figure 1 As shown, a real-time correction system for a swept-frequency optical interferometric ranging measurement reference includes:

[0064] Light source module 1: Input light source 11, second optical isolator 12, 1×2 coupler 13;

[0065] Measurement reference module 2: Optical isolator 21, interferometer under test 22, temperature sensor 23;

[0066] Spatial distance measurement module 3: Circulator 31, fiber optic microprobe with reference surface 32;

[0067] Short-stroke displacement stage module 4: Target object 1 41, Target object 2 42, Fixed bracket 43, Displacement stage 44;

[0068] Signal acquisition module 5: photodetector 51, data acquisition card 52;

[0069] Calibration module 6: Fiber optic microprobe 61, reference laser interferometer 62;

[0070] Data processing module 7: Computer 71; Data transmission line 1 72; Data transmission line 2 73.

[0071] The broadband optical signal generated by the input light source 11 is protected by a second optical isolator 12 for unidirectional transmission and then injected into the a1 input port of the 1×2 fiber coupler 13. The beam is split into two paths: one path enters the measurement reference module 2 through the a2 output port, and the other path is transmitted to the c1 port of the circulator 31 in the spatial distance measurement module 3 through the a3 output port. In the measurement reference module, the optical signal is injected into the interferometer under test 22 after passing through the optical isolator 21. The return signal is output to the photodetector 51 through the d1 port. The temperature sensor 23 collects the ambient temperature field parameters in real time, and a temperature-optical delay compensation model is established through the data acquisition card 52. In the spatial distance measurement module 3, the c2 port of the circulator 31 guides the optical signal into the fiber microprobe 32 containing the reference surface. The surface reflection signal returns to the photodetector 51 through the c3 port for interference fringe demodulation. The short-stroke displacement stage module 4 controls the linear motion of target object 41 and target object 42 along the fixed support 43 via the high-precision displacement stage 44. The data acquisition card 52 synchronously records the interference signal and the reference displacement output by the reference laser interferometer 62. The computer 71, through a dual-channel data transmission line, performs Hilbert phase deconstruction on the original interference signal to obtain the initial ranging value, and corrects the reference length by combining the dual-channel step displacement value. On the other hand, it establishes a real-time correction model using the least squares method, and corrects the time-varying error of the measurement reference by combining it with a temperature feedback mechanism, ultimately achieving real-time maintenance of sub-micron level measurement accuracy in a variable temperature environment.

[0072] The 1×2 coupler 13, optical isolator 21, circulator 31, and fiber optic microprobe 32 all use single-mode fiber optic devices; the initial measurement environment temperature of the interferometer arm length difference 22 under test is controlled at 23℃±0.5℃ to ensure that the refractive index is 1.4682.

[0073] The resolution of temperature sensor 23 0.01℃, accuracy 0.05℃ is used for real-time monitoring of the temperature of the interferometer to be calibrated; the input light source 11 adopts triangular wave modulation, with a tuning range >40 GHz and a repetition frequency >1 kHz, in order to achieve high-precision and high-speed ranging.

[0074] The signal acquisition module 5 normalizes the acquired interference signal and uses the two-beam interferometric phase comparison method to demodulate the phase information in order to improve the measurement accuracy.

[0075] The target object driving module 4 uses a short-stroke high-precision displacement stage 44, with a stroke... Step resolution ;

[0076] The arm length difference of the interferometer under test 22 was calibrated. During the process, the ambient temperature is monitored in real time by a temperature sensor (controlled at 23℃±0.5℃), and the effect of temperature fluctuation on optical path difference is reduced by using delayed fiber refractive index compensation technology.

[0077] like Figure 3 As shown, the interferometer arm length difference corrected using this invention fluctuates by only 0.8 μm over 30 minutes. This invention achieves high-precision, real-time dynamic calibration of the auxiliary interferometer arm length difference. Under dynamic temperature fluctuations of ±10℃, the optical path difference calibration error of this invention is... Repeatability standard deviation The calibration efficiency is improved by 50% compared with the traditional solution, and it is suitable for MEMS device testing, optical precision processing and other scenarios.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A real-time correction system for a sweeping optical interferometric ranging reference, characterized in that: It includes a light source module (1), a temperature sensor (23), a circulator (31), a fiber optic microprobe with a reference surface (32), a short-stroke displacement stage module (4), and a reference laser interferometer (62). The short-stroke displacement stage module (4) includes a first target object (41), a second target object (42), a fixed support (43), and a displacement stage (44); the displacement stage (44) is used to control the first target object (41) and the second target object (42) to move linearly along the fixed support (43); The light signal output by the light source module (1) is divided into two paths. One path passes through the optical isolator (21) and is input to the interferometer under test (22). The other path passes through the circulator (31) and the fiber micro probe (32) with the reference surface and is transmitted to the first target object (41). The first target object (41) reflects the light signal back to the circulator (31). The optical signal output by the reference laser interferometer (62) is transmitted to the second target object (42) after passing through the fiber optic microprobe (61), and the second target object (42) reflects the optical signal back to the reference laser interferometer (62).

2. The real-time correction system for a swept-frequency optical interferometric ranging measurement reference according to claim 1, characterized in that: It also includes a signal acquisition module for acquiring the output of the interferometer under test (22), the light signal reflected back to the circulator (31) by the first target object (41), the output of the reference laser interferometer (62), and the ambient temperature measured in real time by the temperature sensor (23).

3. The real-time correction system for a sweeping optical interferometric ranging measurement reference according to claim 1, characterized in that: The light source module (1) includes an input light source (11), a second optical isolator (12) and a coupler (13); the optical signal generated by the input light source (11) is protected by the second optical isolator (12) for unidirectional transmission and then injected into the optical fiber coupler (13); the optical fiber coupler (13) splits the optical signal into two paths.

4. The real-time correction system for a sweeping optical interferometric ranging measurement reference according to claim 3, characterized in that: The coupler (13), optical isolator (21), circulator (31) and fiber microprobe (32) are all single-mode fiber devices.

5. A method for real-time correction of a sweeping optical interferometric ranging measurement reference system based on claim 1, characterized in that: Step 1: Measure the initial ambient temperature using temperature sensor (23). The arm length difference of the interferometer under test (22) is calibrated. ; Step 2: According to the task requirements, drive target object 1 (41) and target object 2 (42) to move linearly along the fixed support (43) using the displacement stage (44); based on the output of the interferometer under test (22) and the light signal reflected back to the circulator (31) by target object 1 (41), use the difference in the calibration arm length of the interferometer under test (22) As a calibration parameter, obtain the step distance measurement value. ; The ambient temperature is measured in real time by the temperature sensor (23). Calculate the optical path difference of the interferometer under test (22). ; in, For the refractive index function of optical fiber, Wavelength; is the temperature coefficient of refractive index.

6. The real-time correction method for a sweeping optical interferometric ranging measurement reference according to claim 5, characterized in that: In step 1, the arm length difference of the interferometer under test (22) is calibrated. Specifically, it includes the following steps: Step 1.1: Obtain the arm length difference of the interferometer under test (22) before correction. The displacement stage (44) is used to advance the displacement step by a preset amount. Drive target object 1 (41) and target object 2 (42) to move in a straight line along the fixed support (43); The step distance measurement value is determined based on the output of the interferometer under test (22) and the light signal reflected back to the circulator (31) by the first target object (41). Based on the output of the reference laser interferometer (62), determine the reference value of the step distance. ; Step 1.2: Based on the preset step size With step distance measurement value Calculate the proportionality coefficient of the displacement response ; Based on the displacement response proportionality coefficient The arm length difference of the interferometer under test (22) is corrected to obtain the arm length difference of the interferometer under test (22) after preliminary correction. ; Step 1.3: Use the arm length difference of the interferometer (22) under test after preliminary correction. As a new correction parameter, the output of the interferometer under test (22) and the optical signal reflected back to the circulator (31) from the first target object (41) are demodulated a second time to obtain the updated step distance measurement value. ; Step 1.4: Based on the updated step distance measurement values Reference value for step distance Calculate the final scaling factor ; According to the final proportional coefficient The arm length difference of the interferometer (22) under test after preliminary correction After further correction, the difference in the calibration arm length of the interferometer under test (22) was obtained. ; 。 7. The real-time correction method for a sweeping optical interferometric ranging measurement reference according to claim 6, characterized in that: The arm length difference of the calibrated interferometer (22) At that time, the initial ambient temperature The temperature is 23℃ ± 0.5℃.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 5 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When executed by a processor, the computer program implements the steps of the method according to any one of claims 5 to 7.

10. A computer program product comprising computer instructions, characterized in that: When executed by a processor, the computer instructions implement the steps of the method according to any one of claims 5 to 7.

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