Ultrahigh-precision null-drift optimization method based on optical fiber ring tail fiber strain control

Abstract

The invention discloses an ultra-high-precision null drift optimization method based on optical fiber ring tail fiber strain control, and belongs to the technical field of optical fiber gyroscopes and optical measurement. The method is characterized in that a polarization-maintaining OFDR is combined with a multi-parameter decoupling technology to test the temperature and the thermal strain in a ring at a certain temperature change rate; performing null drift forecasting of the loop to obtain a null drift value of each temperature point; setting the length of strain control, and calculating the strain control value and direction of each temperature point by adjusting the tail fiber value in the test data; and under the same temperature condition, applying the strain of the corresponding temperature point in the corresponding direction by using the electric control tension table, and accurately correcting the null drift of each temperature point. According to the method, ultrahigh-precision full-temperature null drift optimization is achieved through active tail fiber strain control, quantitative ultrahigh-precision (10 <-5 > magnitude) null drift optimization can be achieved theoretically, the method can be used for development and online null drift compensation of an ultrahigh-precision gyroscope system, and the method plays an important role in performance improvement of the gyroscope system.

Description

Technical Field

[0001] The invention belongs to the field of fiber optic gyroscopes and optical measurements, and relates to an ultra-high precision zero drift range optimization method based on fiber ring pigtail strain control. Background Art

[0002] Fiber optic gyroscope is a high-precision angular rate sensor based on Sagnac effect. Compared with traditional mechanical gyroscope, fiber optic gyroscope has no rotating parts and wear parts, and has the advantages of short response time, strong vibration and shock resistance, low cost, long life, large dynamic range and simple production process. Compared with laser gyroscope, fiber optic gyroscope does not require ultra-high precision optical processing, and has outstanding advantages such as low power consumption and good reliability. Therefore, fiber optic gyroscope is widely used in navigation and guidance in military aviation, aerospace and navigation fields.

[0003] The fiber-optic sensitive ring is one of the core components of the fiber-optic gyroscope and is known as the "brain" of the fiber-optic gyroscope. In the actual operation of the fiber-optic gyroscope, both internal heating and temperature disturbances in the external environment will affect it. When a section of optical fiber in the fiber-optic sensitive ring has a time-varying temperature disturbance, unless the section of optical fiber is located at the midpoint of the fiber-optic sensitive ring's geometric structure, a non-reciprocal phase shift will inevitably occur. This non-reciprocal phase shift cannot be distinguished from the phase shift caused by rotation, causing the fiber-optic gyroscope to have a large drift error, which directly affects its output accuracy.

[0004] The physical symmetry of the fiber optic sensitive ring describes its related physical and material properties, including the material's temperature coefficient, temperature distribution, and the symmetry of thermal strain distribution. Under the influence of the temperature field, thermal strain will lead to the deterioration of physical symmetry, thereby causing the Mohr effect and the Shupe effect at the same time. These effects significantly promote the thermal drift in the fiber optic gyroscope system. At present, in the manufacturing process of the fiber optic sensitive ring, quadrupole, octupole and hexadecanopole symmetrical winding are mainly used to ensure the midpoint symmetry of the structural position, so as to ensure the symmetry of the physical field distribution as much as possible.

[0005] In 2017, Liu Bohan and others from the 707th Institute of China Shipbuilding Industry Corporation proposed to compensate for the stress of the sensitive fiber loop by changing the colloid modulus, bending radius or winding tension of the specific number of turns of the pigtail, effectively reducing its non-reciprocity error. (A method for compensating the number of turns of the pigtail stress of the fiber optic gyroscope loop, CN 201711351950.9)

[0006] In 2020, Huang Zhongwei of Beijing Sizhuoborui Technology Co., Ltd. proposed adding temperature sensors and piezoelectric ceramics to the fiber optic gyroscope test system, winding the pigtail of one side of the fiber optic sensitive ring on the piezoelectric ceramic, and controlling the piezoelectric ceramic in real time according to the sensitive angular rate information and temperature information when the gyro system is working, so as to apply stress to the pigtail to compensate for the zero drift of the fiber optic gyroscope. (Fiber optic gyroscope with stress compensation, CN 202010586507.5)

[0007] In 2022, Liu Bohan and others proposed to fix the fiber length compensator on the pigtail of the fiber sensitive ring. When the fiber optic gyroscope output drift is detected, the length of the outer fiber ring is changed by adjusting the linear expansion coefficient of the expansion and contraction axis core in the fiber length compensator, thus realizing the online adjustment of the fiber pigtail of the fiber optic gyroscope. (Fiber optic gyroscope ring pigtail compensation method and fiber length compensator, CN202210915632.5)

[0008] The above methods for detecting thermal drift of optical fiber sensitive rings all place the optical fiber sensitive rings on the gyro system for system-level testing. However, such testing has high noise and is easily affected by environmental interference. In addition, system-level testing can only give the final system performance but cannot reflect the impact of the optical fiber sensitive ring on the system performance. On the other hand, the above methods optimize the zero drift performance of the optical fiber sensitive ring by controlling the pigtail stress at different temperature points. It is impossible to accurately and quantitatively control the output stress size, and thus it is difficult to meet the increasing demand for zero drift optimization of the optical fiber sensitive ring.

[0009] In view of the problem that the current zero drift optimization of optical fiber sensitive rings is complicated in operation and cannot accurately compensate stress at all temperature points to achieve the best zero drift optimization, the present invention discloses an ultra-high precision zero drift optimization method based on strain control of optical fiber ring pigtails. Based on the principle of controlling the stress of the optical fiber sensitive ring pigtail to adjust its physical symmetry and thus optimize zero drift, the electric-controlled displacement stage is used to continuously and accurately apply stresses of different magnitudes to the pigtail on one side of the optical fiber sensitive ring at each temperature point under a continuous temperature change field to achieve the goal of optimizing its zero drift performance. It has significant advantages such as accurate quantitative optimization of zero drift at different temperature points and simple operation steps. Summary of the invention

[0010] The purpose of the present invention is to propose an ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control, which solves the problem of the difficulty in quantitatively optimizing the zero drift of the optical fiber sensitive ring at different temperature points in the background technology.

[0011] 1. An ultra-high precision zero drift optimization method based on strain control of optical fiber ring pigtail, characterized in that, based on the principle of controlling the stress of the optical fiber sensitive ring pigtail to adjust its physical symmetry to optimize the zero drift, different stresses are applied to the pigtails on the left and right sides of the optical fiber sensitive ring at each temperature point under a continuous temperature change field through an electric control displacement stage to achieve zero drift performance optimization of the optical fiber sensitive ring. The specific process is as follows:

[0012] Step 1 (101): placing the optical fiber sensitive ring (501) to be optimized in a temperature box (504), testing the optical fiber sensitive ring (501) using a polarization-maintaining OFDR multi-parameter testing device under a continuous temperature change field, and obtaining corresponding temperature and thermal strain change data;

[0013] Step 2 (102): Decouple the measured temperature and thermal strain change data to obtain the refractive index change α T ;

[0014] Step 3 (103): Calculate the refractive index change α obtained in step 2 (102) T , the zero drift prediction result Z0 of the optical fiber sensitive ring (501) with temperature change under full temperature test can be obtained, and the corresponding zero drift optimization target Z2 can be set at the same time;

[0015] Step 4 (104): The pigtails on both sides of the optical fiber sensitive ring (501) are respectively fused with a length L1 of polarization-maintaining optical fiber with the same process and specifications and fixed to the first electrically controlled displacement stage (502) and the second electrically controlled displacement stage (503), and the shortest controllable length L2 of the displacement stage is measured at the same time, satisfying L2>L1;

[0016] Step 5 (105): Apply different stress magnitudes F to the pigtails on the left and right sides of the optical fiber sensitive ring (501) respectively. 左min and F 右min , adjusting the magnitude of the thermal strain on the left and right sides of the optical fiber sensitive ring (501);

[0017] Step 6 (106): recalculate the zero drift value Z1 of the optical fiber sensitive ring (501) at each temperature point, and compare whether Z1 and Z0 are equal. If they are equal, proceed to step 7 (107); if they are not equal, return to step 5 (105) and readjust the stress F applied to both sides of the pigtail. 左min and F 右min size;

[0018] Step 7 (107): Record the stress magnitude F corresponding to the thermal strain adjustment on the left and right sides of the optical fiber sensitive ring (501) at each temperature point. 左min and F 右min ;

[0019] Step eight (108): placing a temperature sensing probe in the temperature box (504) and starting it to monitor its temperature changes in real time;

[0020] Step nine (109): According to the reading of the placed temperature sensor probe, the corresponding stress F is applied to the left and right side pigtails of the optical fiber sensitive ring (501) through the electric control displacement stage according to the record of step seven (107). 左min and F右min ;

[0021] Step 10 (110): After the adjustment is completed, the thermal strain at this temperature point is read and the optimization of the zero drift is calculated based on the thermal strain F required to be applied to the corresponding side direction of the pigtail of the optical fiber sensitive ring (501). min stress;

[0022] Step 11 (111): At this temperature point, a stress F is precisely applied to the pigtail on one side of the optical fiber sensitive ring (501) through an electric-controlled displacement stage. min ;

[0023] Step 12 (112): Perform a secondary zero drift prediction Z3 and compare it with the set zero drift optimization target Z2;

[0024] Step 13 (113): Determine whether the temperature point of this zero drift optimization is the zero drift optimization of the optical fiber sensitive ring (501) under the full temperature test. If it is not the last temperature point in the full temperature test process, repeat steps 9 (109) to 12 (112) to apply different stress magnitudes F to the optical fiber sensitive ring (501) at each temperature point under the temperature test curve. min , so that the zero drift result at the corresponding temperature point is optimal; if it is the last temperature point of the temperature test curve, the full-temperature zero drift range optimization of the optical fiber ring is completed;

[0025] 2. An ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control according to claim 1, characterized in that the polarization-maintaining OFDR multi-parameter measurement device in step 1 (101) comprises a light source (10), a 45-degree polarizer (101), a first polarization-maintaining coupler (102), an auxiliary interferometer module (20), a main interferometer module (30), a data acquisition and processing module (40), an optical fiber sensitive ring (501), a first electrically controlled displacement stage (502), a second electrically controlled displacement stage (503) and a temperature box (504); the continuous frequency sweeping light emitted by the light source 10 first passes through the 45-degree polarizer (101) to adjust the polarization state of the injected light to 45°, and then is divided into two beams through the first polarization-maintaining coupler (102); 1% of the optical signal is injected into the auxiliary interferometer module (20) to generate an auxiliary interference signal for eliminating the main interferometer module (30) Outputting the phase noise of the beat frequency signal; in addition, injecting 99% of the optical signal into the main interferometer module (30), and then passing through the second polarization-maintaining coupler (301) to be divided into two beams, injecting 1% of the optical signal into the reference arm, and injecting 99% of the optical signal into the measurement arm where the polarization-maintaining circulator (302) is located, and then passing through the polarization-maintaining circulator 302 to enter the optical fiber sensitive ring (501) to be optimized, and the reflected signal light passes through the polarization-maintaining circulator (302) again and then merges; the main interference signal passes through the first and second polarization beam splitters (304) and (305) respectively, and then enters the first photoelectric balanced detector (307) and the second photoelectric balanced detector (308) respectively to convert the optical signal into an electrical signal, and finally the auxiliary interference signal and the main interference signal are respectively collected by the acquisition card (401) in the data acquisition and processing module (40), and the data is transmitted to the computer terminal (402);

[0026] 3. An ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control according to claim 1, characterized in that the zero drift prediction result Z0(i) of the optical fiber sensitive ring (501) changing with temperature under full temperature test in step three (103) and the set corresponding zero drift optimization value Z2(i), i is the i-th temperature point, i=1,2,3...N, N is the total number of temperature points.

[0027] Refractive index change α under thermal strain T The expression is:

[0028] (1)

[0029] Where n0 is the standard refractive index, p 11 、p 12 is the photoelastic coefficient, ε θ is the axial thermal strain, n T is the thermo-optical coefficient of the optical fiber.

[0030] The CW light of the fiber sensitive ring is disturbed by the external temperature at point s, which causes a change in the refractive index and leads to a positive phase difference. Similarly, the CCW light will also have a change in the refractive index at Ls, but a negative phase difference will be generated. Therefore, the two beams produce different refractive index changes on the symmetrical length, which is called the asymmetric distribution of refractive index α Ts . Asymmetric distribution of refractive index α Ts The expression is as follows:

[0031] (2)

[0032] Asymmetric distribution of refractive index α Ts The relationship between and thermal drift is expressed as follows:

[0033] (3)

[0034] The expression of the moving distance ∆l of the electric-controlled translation stage when stress control is applied to the pigtail is as follows:

[0035] (4)

[0036] Compared with the existing optimization method, the advantages of the present invention are:

[0037] The present invention proposes a method for achieving ultra-high precision full-temperature zero drift optimization based on active pigtail strain control, which can theoretically achieve quantitative ultra-high precision (10 -5 Zero drift optimization of the order of magnitude).

[0038] The optimization method proposed in the present invention can accurately and quantitatively compensate for the different stress sizes required by the optical fiber sensitive ring at each temperature point in the full-temperature test through an electrically controlled displacement stage; compared with the traditional method of not being able to finely control the output stress through piezoelectric ceramics or changing the pigtail colloid modulus, quantitative optimization of zero drift can be achieved.

[0039] The optimization method proposed in the present invention is simple to operate and can be widely used in the winding of different optical fiber categories and in optimizing the zero drift performance of optical fiber sensitive rings with different winding processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] To more clearly illustrate the device design of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention, wherein the drawings are only used to illustrate some embodiments of the present invention, but not to limit all embodiments of the present invention thereto.

[0041] Figure 1 It is a flow chart of an ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control;

[0042] Figure 2 This is a diagram of the device for polarization-maintaining OFDR multi-parameter testing;

[0043] Figure 3 It is a graph showing the temperature changing with time in the full temperature test;

[0044] Figure 4 is the refractive index change α T Graphs that vary with fiber length;

[0045] Figure 5 This is the zero drift result diagram of the optical fiber sensitive ring at different temperature points;

[0046] Figure 6 It is the displacement distance diagram of the electric-controlled translation stage at different temperature points controlled by the stress applied by the pigtail;

[0047] Figure 7 It is the best zero drift curve after optimization of the optical fiber ring theory based on pigtail stress control. DETAILED DESCRIPTION

[0048] In order to more clearly explain the application objectives, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with embodiments and drawings, but the protection scope of the present invention should not be limited thereby. Specific embodiment 1

[0050] An ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control, the specific operation steps are as follows:

[0051] Step 1: Place the optical fiber sensitive ring to be optimized in a temperature box, and perform high spatial resolution OFDR multi-parameter test on the optical fiber sensitive ring under a continuous temperature change field to obtain the corresponding temperature and thermal strain change data;

[0052] like Figure 2 The figure shows the polarization-maintaining OFDR multi-parameter test device used in step 1 of this embodiment. The selection of the main optoelectronic devices in the device and their parameters are as follows:

[0053] The light source 10 is a narrow linewidth tunable laser source, the linewidth of the light source is 70kHz, the wavelength tuning range is set to 1545nm~1555nm, the sweep rate is 10nm / s, and the sweep time is 1s;

[0054] The maximum detection bandwidth of the first balanced photodetector 306 and the second balanced photodetector 307 are both 80 MHz, and the peak-to-peak value of the electrical noise in the time domain V P-P <30 mV with a conversion gain of 4×104 V / W.

[0055] The sampling rate of acquisition card 401 is set to 180MHz / s. After compensation, its effective number of bits is 8.6 bits, the spurious-free dynamic range is 67.4 dB, and the no-load electrical noise is VP-P =2.8 mV.

[0056] The first coupler 102, the second coupler 301 and the third coupler 303 are all polarization-maintaining couplers. The splitting ratios of the first polarization-maintaining coupler 101 and the second polarization-maintaining coupler 301 are both 99:1, and the splitting ratio of the third polarization-maintaining coupler 303 is 50:50.

[0057] The auxiliary interferometer module 20 adopts a Mach-Zehnder interferometer, and the refractive index of the single-mode optical fiber used is 1.456.

[0058] The fiber optic sensitive ring 501 is wound with panda-type polarization-maintaining optical fiber.

[0059] The temperature change of the temperature box 504 during the full temperature test of the optical fiber sensitive ring 501 is as follows: Figure 3 As shown in the figure, the specific process is: first keep the temperature at 25℃ for 20 minutes; then cool down to -45℃ at a temperature change rate of 1℃ / min, and it takes 70 minutes to cool down; then keep the temperature at -45℃ for 60 minutes, and then heat up to 70℃ at a temperature change rate of 1℃ / min, and it takes 115 minutes to heat up; finally keep the temperature at 70℃ for 60 minutes, and the full temperature test is over. From the beginning of the full temperature test, every 5℃ is a temperature point.

[0060] The first electrically controlled stage 502 and the second electrically controlled stage 503 for applying stress control to the pigtail are set to have a resolution of 0.1 μm / pulse for full step.

[0061] The specific implementation method of testing the fiber sensitive ring by the polarization-maintaining OFDR multi-parameter test device in step 1 is as follows: the fiber sensitive ring 501 is placed in the temperature box 504, and the temperature change curve is set. The continuous frequency sweeping light emitted by the light source 10 first passes through the 45° polarizer 101 to adjust the polarization state of the injected light to 45°, and then is divided into two beams by the first polarization-maintaining coupler 102. 1% of the light signal is injected into the auxiliary interferometer module 20 to generate an auxiliary interference signal for eliminating the phase noise of the beat signal output by the main interferometer module 30; in addition, 99% of the light signal is injected into the main interferometer module 30. After that, the polarized light is divided into two beams through the second polarization-maintaining coupler 301, and 1% of the light signal is injected into the reference arm; 99% of the light signal is injected into the measurement arm where the polarization-maintaining circulator 302 is located, and then enters the optical fiber sensitive ring 501 to be optimized through the polarization-maintaining circulator 302, and the reflected signal light is merged after passing through the polarization-maintaining circulator 302 again; the main interference signal passes through the polarization beam splitters 304 and 305 respectively, and enters the first photoelectric balance detector 307 and the second photoelectric balance detector 308 respectively to convert the light signal into an electrical signal. The acquisition card 401 in the data acquisition and processing module 40 collects the auxiliary interference signal and the main interference signal generated by the main interference module 30, and transmits the data to the computer terminal 402.

[0062] Step 2: Decoupling the measured temperature data and thermal strain data can calculate the refractive index change α T , refractive index change α T The calculation formula is:

[0063]

[0064] Refractive index change α T As the length of the optical fiber changes Figure 4 shown.

[0065] Step 3: The refractive index change α calculated in step 2 T , we can get the asymmetric distribution of refractive index α Ts , the expression is:

[0066]

[0067] Through the uneven distribution of refractive index α Ts The relationship between and thermal drift is expressed as:

[0068]

[0069] Thus, the zero drift prediction result Z0 of the optical fiber sensitive ring with temperature change under full temperature test can be obtained, such as Figure 5 As shown, the corresponding zero drift optimization target Z2 is set at the same time.

[0070] Step 4: The pigtails on both sides of the optical fiber sensitive ring are respectively fused with a length L1 of polarization-maintaining optical fiber with the same process and specifications and fixed on the first electrically-controlled translation stage 502 and the second electrically-controlled translation stage 503, and their shortest controllable length L2 is measured at the same time, satisfying L2>L1.

[0071] Step 5: Apply different stress magnitudes F to the pigtails on the left and right sides of the optical fiber sensitive ring. 左min and F 右min , adjust the size of thermal strain on the left and right sides of the optical fiber sensitive ring.

[0072] Step 6: Recalculate the zero drift value Z1 of the optical fiber sensitive ring at each temperature point, and compare whether Z1 and Z0 are equal. If they are equal, go to step 7; if not, return to step 5 to re-adjust the stress F applied to both sides of the pigtail. 左min and F 右min size.

[0073] Step 7: Record the stress F corresponding to the thermal strain adjustment on the left and right sides of the optical fiber sensitive ring at each temperature point 左min and F 右min .

[0074] Step 8: Place a temperature sensor probe in the incubator, start the incubator, and monitor temperature changes in real time.

[0075] Step 9: According to the reading of the temperature sensor probe placed in the temperature box, apply corresponding stress F to the left and right side pigtails of the optical fiber sensitive ring through the electric control displacement stage according to the record of step 7. 左min and F 右min .

[0076] Step 10: After the adjustment is completed, read the thermal strain at this temperature point and calculate the direction and magnitude of the stress F that needs to be applied to the optical fiber sensitive ring to optimize the zero drift. min , since the magnitude of the applied stress is controlled by the electric-controlled translation stage, it can be converted into the magnitude of the displacement distance of the electric-controlled translation stage, such as Figure 6 shown.

[0077] Step 11: At this temperature point, the electro-controlled displacement stage is used to precisely apply stress F to the pigtail on one side of the optical fiber sensitive ring. min .

[0078] Step 12: Perform a secondary zero drift forecast Z3 and compare it with the set zero drift optimization target Z2.

[0079] Step 13: Determine whether the temperature point of this zero drift optimization is the zero drift optimization of the optical fiber ring under the full temperature test. If it is not the last temperature point in the full temperature test process, repeat steps 9 (109) to 12 (112) to apply different stress magnitudes F to the optical fiber sensitive ring at each temperature point under the temperature test curve. min , so that the zero drift result at the corresponding temperature point is optimal; if it is the last temperature point of the temperature test curve, the full-temperature zero drift range optimization of the optical fiber ring is completed, such as Figure 7 shown.

[0080] The above embodiments describe in detail some implementation methods of an ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control proposed by the present invention. However, for those skilled in the art, various modifications and variations can be made to the above specific embodiments without departing from the principles of the present invention, and various technical features and structures proposed by the present invention can be combined in different ways, but they do not exceed the protection scope of the present invention, and these should be regarded as the protection scope of the present invention.

Claims

1. An ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control, characterized in that: Based on the principle of controlling the stress of the fiber pigtail of the optical fiber sensitive ring to adjust its physical symmetry and thus optimize the zero drift, different stresses are applied to the pigtails on the left and right sides of the optical fiber sensitive ring at each temperature point under the continuous temperature change field through the electric control displacement stage to achieve the optimization of the zero drift performance of the optical fiber sensitive ring. The specific process is as follows: Step 1 (101): placing the optical fiber sensitive ring (501) to be optimized in a temperature box (504), testing the optical fiber sensitive ring (501) using a polarization-maintaining OFDR multi-parameter testing device under a continuous temperature change field, and obtaining corresponding temperature and thermal strain change data; Step 2 (102): Decouple the measured temperature and thermal strain change data to obtain the refractive index change α T ; Step 3 (103): Calculate the refractive index change α obtained in step 2 (102) T , the zero drift prediction result Z0 of the optical fiber sensitive ring (501) with temperature change under full temperature test can be obtained, and the corresponding zero drift optimization target Z2 can be set at the same time; Step 4 (104): The pigtails on both sides of the optical fiber sensitive ring (501) are respectively fused with a length L1 of polarization-maintaining optical fiber with the same process and specifications and fixed to the first electrically controlled displacement stage (502) and the second electrically controlled displacement stage (503), and the shortest controllable length L2 of the displacement stage is measured at the same time, satisfying L2>L1; Step 5 (105): Apply different stress magnitudes F to the pigtails on the left and right sides of the optical fiber sensitive ring (501) respectively. 左min and F 右min , adjusting the magnitude of the thermal strain on the left and right sides of the optical fiber sensitive ring (501); Step 6 (106): recalculate the zero drift value Z1 of the optical fiber sensitive ring (501) at each temperature point, and compare whether Z1 and Z0 are equal. If they are equal, proceed to step 7 (107); if they are not equal, return to step 5 (105) and readjust the stress F applied to both sides of the pigtail. 左min and F 右min size; Step 7 (107): Record the stress magnitude F corresponding to the thermal strain adjustment on the left and right sides of the optical fiber sensitive ring (501) at each temperature point. 左min and F 右min ; Step eight (108): placing a temperature sensing probe in the temperature box (504) and starting it to monitor its temperature changes in real time; Step nine (109): According to the reading of the placed temperature sensor probe, the corresponding stress F is applied to the left and right side pigtails of the optical fiber sensitive ring (501) through the electric control displacement stage according to the record of step seven (107). 左min and F 右min ; Step 10 (110): After the adjustment is completed, the thermal strain at this temperature point is read and the optimization of the zero drift is calculated based on the thermal strain F required to be applied to the corresponding side direction of the pigtail of the optical fiber sensitive ring (501). min stress; Step 11 (111): At this temperature point, a stress F is precisely applied to the pigtail on one side of the optical fiber sensitive ring (501) through an electric-controlled displacement stage. min ; Step 12 (112): Perform a secondary zero drift prediction Z3 and compare it with the set zero drift optimization target Z2; Step 13 (113): Determine whether the temperature point of this zero drift optimization is the zero drift optimization of the optical fiber sensitive ring (501) under the full temperature test. If it is not the last temperature point in the full temperature test process, repeat steps 9 (109) to 12 (112) to apply different stress magnitudes F to the optical fiber sensitive ring (501) at each temperature point under the temperature test curve. min , so that the zero drift result at the corresponding temperature point is optimal; If it is the last temperature point of the temperature test curve, the full-temperature zero-drift range optimization of the optical fiber ring is completed.

2. An ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control according to claim 1, characterized in that: The polarization-maintaining OFDR multi-parameter measurement device in step 1 (101) comprises a light source (10), a 45-degree polarizer (101), a first polarization-maintaining coupler (102), an auxiliary interferometer module (20), a main interferometer module (30), a data acquisition and processing module (40), an optical fiber sensitive ring (501), a first electrically controlled displacement stage (502), a second electrically controlled displacement stage (503) and a temperature box (504). The continuously swept light emitted by the light source 10 first passes through the 45-degree polarizer (101) to adjust the polarization state of the injected light to 45 degrees, and then passes through the first polarization-maintaining coupler (102) to be divided into two beams, 1% of the light signal is injected into the auxiliary interferometer module (20) to generate an auxiliary interference signal for eliminating the phase noise of the beat frequency signal output by the main interferometer module (30); and 99% of the light signal is injected into the auxiliary interferometer module (20) to generate an auxiliary interference signal for eliminating the phase noise of the beat frequency signal output by the main interferometer module (30). The optical signal is injected into the main interferometer module (30), and then is divided into two beams through the second polarization-maintaining coupler (301), 1% of the optical signal is injected into the reference arm, and 99% of the optical signal is injected into the measurement arm where the polarization-maintaining circulator (302) is located, and then enters the optical fiber sensitive ring (501) to be optimized through the polarization-maintaining circulator 302, and the reflected signal light is merged after passing through the polarization-maintaining circulator (302) again; the main interference signal passes through the first and second polarization beam splitters (304) and (305), and respectively enters the first photoelectric balance detector (307) and the second photoelectric balance detector (308) to convert the optical signal into an electrical signal, and finally the auxiliary interference signal and the main interference signal are respectively collected through the acquisition card (401) in the data acquisition and processing module (40), and the data is transmitted to the computer terminal (402).

3. The ultra-high precision zero drift optimization method based on optical fiber ring pigtail strain control according to claim 1 is characterized in that: The zero drift prediction result Z0(i) of the optical fiber sensitive ring (501) with temperature change under the full temperature test in step three (103) and the set corresponding zero drift optimization value Z2(i), i is the i-th temperature point, i=1,2,3...N, N is the total number of temperature points.

Images