Temperature test and evaluation system for polarization-maintaining optical path assembly of fiber-optic gyroscope

Abstract

The invention relates to a temperature test and evaluation system for a polarization-maintaining optical path assembly of a fiber-optic gyroscope. The polarization-maintaining light path assembly and the test tool thereof are placed in a temperature box with a vibration isolation foundation. Other optical devices and a gyro circuit are arranged outside the incubator. And the power box, the fiber-optic gyroscope and the acquisition equipment are electrically connected through the test cable. Before the temperature test, the output of the normal-temperature fiber-optic gyroscope is electrified and monitored, the acquisition time is set, the mean value and the standard deviation of normal-temperature output data are calculated, and the temperature test can be started after the requirements are met. And according to the full-temperature output data, calculating extreme values and standard deviations before and after temperature compensation to jointly form evaluation indexes of the polarization-maintaining optical path assembly. According to the system disclosed by the invention, the full-temperature zero-bias stability qualification rate is improved after the fiber-optic gyroscope product is compensated.

Description

Technical Field

[0001] The invention relates to a temperature testing and evaluation system for a polarization-maintaining optical path component of an optical fiber gyroscope. Background Art

[0002] The polarization-maintaining optical path component is composed of an optical fiber ring and a Y-waveguide integrated optical device, a double-ended fiber pigtail of the optical fiber ring, a double-ended fiber pigtail of the Y-waveguide, and two polarization-maintaining fusion points, forming a Sagnac interferometer in the fiber optic gyroscope. In the polarization-maintaining optical path component, the light wave signal is split at the Y-waveguide, propagates in opposite directions through the optical fiber ring, and then combined at the Y-waveguide to become an interference signal. The fiber optic gyroscope uses the interference signal as a carrier to achieve sensitivity to angular velocity.

[0003] Polarization-maintaining optical path components are the core sensitive components of fiber optic gyroscopes, and their performance directly affects the accuracy of fiber optic gyroscopes. The temperature characteristics of polarization-maintaining optical path components are affected by the winding process of the fiber ring, Y waveguide, fiber ring double-ended pigtail, Y waveguide double-ended pigtail, and the welding quality of two polarization-maintaining fusion points. In particular, the temperature characteristics of the fiber ring restrict the full-temperature zero-bias stability of the fiber optic gyroscope. The Y waveguide integrated optical device has the functions of polarization, bias, and modulating light waves, and is also easily affected by temperature. Compared with the test of only a certain optical device, such as fiber ring and Y waveguide, the test of polarization-maintaining fusion points, polarization-maintaining pigtails (including fiber ring pigtails and Y waveguide pigtails), and winding process are added. For high-precision fiber optic gyroscopes, under full temperature conditions: temperature range -40℃~+60℃, temperature change rate: 1℃ / min, the accuracy requirement after compensation is not more than 0.01° / h (100s, 1σ), and the influence of polarization-maintaining fusion points and winding process cannot be ignored. In the past, only the temperature performance of a single optical device was focused on, which could not meet the temperature requirements of high-precision and very high-precision fiber optic gyroscopes.

[0004] Fiber optic ring double-ended pigtail and Y-waveguide double-ended pigtail are both polarization-maintaining fibers. The polarization-maintaining pigtail is coiled and fused, and the stresses on both ends are different, which is also easily affected by temperature. Screening the temperature performance of fiber optic ring and Y-waveguide alone ignores the coiling process of fiber optic ring double-ended pigtail and Y-waveguide double-ended pigtail, as well as the fusion quality of two polarization-maintaining fusion points, which is not enough to represent the temperature characteristics of the entire polarization-maintaining optical path component. Therefore, in order to ensure the full temperature accuracy of the fiber optic gyroscope and improve the qualified rate of the fiber optic gyroscope, it is more practical to screen the temperature characteristics of the entire polarization-maintaining optical path component.

[0005] At present, many scholars have established a fiber ring temperature test and evaluation system to determine the temperature performance of the fiber ring. A high-precision optical waveguide full-temperature screening test method has been established to test the temperature performance of Y-waveguide integrated optical devices. These detection methods only perform temperature screening on individual devices. It is difficult to unilaterally evaluate the temperature index of polarization-maintaining optical path components and cannot accurately represent the temperature performance of the fiber gyroscope. Therefore, it is particularly important to build a polarization-maintaining optical path component temperature test and evaluation system. Summary of the invention

[0006] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and provide a temperature testing and index evaluation system for polarization-maintaining optical path components of a fiber optic gyroscope, by which the full-temperature zero-bias stability qualified rate of fiber optic gyroscope products after compensation can be improved.

[0007] The technical scheme of the present invention is: a temperature test and evaluation system for a polarization-maintaining optical path component of an optical fiber gyroscope, comprising an erbium-doped optical fiber light source, an optical fiber coupler, a polarization-maintaining optical path component, a detector, a temperature sensor, a light source driving circuit and a digital circuit, a test fixture, a test cable, an evaluation unit and a temperature box; wherein the polarization-maintaining optical path component comprises a Y waveguide and an optical fiber ring; one side of the Y waveguide is provided with two sections of polarization-maintaining pigtails, and the optical fiber ring is provided with two sections of polarization-maintaining pigtails; a closed loop is formed by welding the two sections of polarization-maintaining pigtails; the welding point between the polarization-maintaining pigtails is called a polarization-maintaining welding point; the optical fiber ring is placed in the test fixture, the temperature sensor is placed in the center of the optical fiber ring coil, and the test fixture is placed in a temperature box with a vibration isolation foundation; the light source driving circuit, the digital circuit, the power supply box and the evaluation unit are electrically connected through a three-port test cable;

[0008] The erbium-doped fiber light source generates a light signal i1 by providing a driving current through a light source driving circuit. The light signal i1 is split by a fiber coupler to form a light signal i2. The light signal i2 reaches the Y waveguide and generates two beams of linearly polarized light after polarization and splitting. The two beams of linearly polarized light successively pass through the polarization-maintaining pigtail and the polarization-maintaining fusion point between the Y waveguide and the fiber ring, and then enter the fiber ring; after propagating through the fiber ring, the two beams of linearly polarized light reversely pass through the polarization-maintaining pigtail and the polarization-maintaining fusion point between the Y waveguide and the fiber ring, and then reach the Y waveguide to combine and form a light signal i3 carrying rotation speed information; the interference signal i3 is split again by a fiber coupler to form a light signal i4 and reaches the detector, and the detector converts the received light signal i4 into an electrical signal; the electrical signal is resolved by a digital circuit to form three signals: an angular velocity signal y1, a modulation signal y2, and a gain error signal y3; the digital circuit is composed of a front-end signal processing circuit, a digital signal processing circuit, and a digital signal processing circuit. The invention is composed of a logic chip and a back-end signal processing circuit; wherein the front-end signal processing circuit includes a filtering circuit, a first amplifying circuit, and an analog-to-digital converter; the back-end signal processing circuit includes a first digital-to-analog converter, a second amplifying circuit, a switching switch, a second digital-to-analog converter, and a third amplifying circuit; the angular velocity signal y1 represents the signal of the gyroscope sensitive to the external angular velocity and is output externally; the modulation signal y2 is used as a feedback signal to compensate the Y waveguide to form a first closed-loop feedback loop; the gain error signal y3 is used as a feedback signal to compensate the first digital-to-analog converter to form a second closed-loop feedback loop to compensate for the gain error caused by the half-wave voltage change of the Y waveguide; the temperature sensor packages the measured fiber ring temperature information with the output angular velocity signal y1 of the gyroscope to form gyroscope data and uploads them together to the evaluation unit; the evaluation unit obtains the evaluation index according to the angular velocity signal y1 and temperature information of the gyroscope.

[0009] The polarization-maintaining fusion point loss is no more than 0.1dB, and the crosstalk value is no less than 35dB; the polarization-maintaining pigtails of the optical fiber ring and the Y-waveguide are coiled in a preset path, and during the coiling process, the optical fiber is ensured to have no twisting, no squeezing, and no hanging.

[0010] The evaluation index includes the range and the compensated standard deviation of the polarization-maintaining optical path component under temperature testing; the range is used to judge the temperature sensitivity of the polarization-maintaining optical path component, and the compensated standard deviation is used to judge the accuracy level of the polarization-maintaining optical path component after compensation.

[0011] The calculation method of the range of the polarization-maintaining optical path component is: firstly, the original data is smoothed for 100 seconds, then the smoothed data is slide-smoothed for 10 seconds, and finally, the maximum value and the minimum value of the slide-smoothed data are found and subtracted to obtain the range.

[0012] The specific calculation process of the extreme difference of the polarization-maintaining optical path component is:

[0013] Assume that the original output angular velocity data of the polarization-maintaining optical path component is B and the sampling time is t, then the data after 100s smoothing is:

[0014]

[0015] Among them, i represents the number of data, Represents the total number of data collected within 100 seconds; mean() represents the average value of all the data in the brackets;

[0016] The data after 100s smoothing is subjected to 10s sliding smoothing to obtain a smoother curve. The data after 10s smoothing is

[0017]

[0018] in, Represents the total number of data collected within 10 seconds;

[0019] Subtract the maximum and minimum values ​​in the smoother curve to obtain the temperature range.

[0020] Before collecting the angular velocity data of the polarization-maintaining optical path component, the polarization-maintaining optical path component was placed in an incubator, and the incubator temperature was set to -40°C for 3 hours, then increased to 60°C at a temperature change rate of 1°C / min and maintained for another 3 hours.

[0021] The calculation method of the standard deviation of the polarization-maintaining optical path component after compensation is:

[0022] Assume the original output angular velocity data is B, the sampling time is t, and the temperature information is T;

[0023] Using the ratio of the temperature difference before and after to the time As the temperature change rate; where T is the temperature information, t is the sampling time, and Δt is the time interval;

[0024] Assume that the derived signal based on temperature information T , T 2 , T 3 , ..., respectively x1, x2, ..., x m ;

[0025] Suppose x1,x2,…,x m variables, the multiple linear regression model is expressed as

[0026] B=β0+β1x1+β2x2+ … +β m x m +ε

[0027] where β0,β1, … β m There are m+1 unknowns. If n sets of observation data are obtained, the linear regression model is

[0028]

[0029] Written in matrix form:

[0030]

[0031] in

[0032]

[0033] The unknowns of the multivariate linear regression equation are usually estimated by least squares.

[0034]

[0035] The sample regression model under ordinary least squares method is

[0036]

[0037] The output angular velocity data after compensation is Seek Standard Deviation As the standard deviation after compensation of polarization-maintaining optical path components.

[0038] Before collecting the angular velocity and temperature data of the polarization-maintaining optical path component, the polarization-maintaining optical path component was placed in an incubator, and the incubator temperature was set to -40°C for 3 hours, then increased to 60°C at a temperature change rate of 1°C / min and maintained for another 3 hours.

[0039] Before starting the test, the system is also tested before the experiment, including:

[0040] Power on at room temperature for 3 hours, obtain the compensated standard deviation of the polarization-maintaining optical path components and the curve of temperature change over time, and use the data of the last 2 hours. If the compensated standard deviation is not greater than 0.05° / h, the system is considered normal and the test data is available;

[0041] The temperature of the incubator is set to -40℃ and +60℃ respectively, and the power is turned on for 3 hours at the two temperatures respectively. The compensated standard deviation of the polarization-maintaining optical path component and the temperature-time curve are obtained. The data of the last 2 hours are used. If the compensated standard deviation is no more than 0.05° / h, the system is considered normal and the test data can be used.

[0042] The advantages of the present invention compared with the prior art are:

[0043] The fiber optic gyro polarization-maintaining optical path component temperature test and evaluation system of the present invention has a test part that performs temperature screening on the polarization-maintaining optical path component temperature, covering the entire path of light waves from light splitting to light combining, and can cover more information than testing a single device. Its evaluation part provides the temperature performance index of the polarization-maintaining optical path component, the temperature extreme difference and the standard deviation after compensation, and provides a criterion for screening the polarization-maintaining optical path component. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the polarization-maintaining optical path component testing system of the present invention.

[0045] Figure 2 This is a test curve of the polarization-maintaining optical path component of the present invention at room temperature.

[0046] Figure 3 This is a test curve of the polarization-maintaining optical path component at a constant temperature point (-40°C) of the present invention.

[0047] Figure 4 This is a test curve of the polarization-maintaining optical path component at a constant temperature point (+60° C.) of the present invention.

[0048] Figure 5 This is a test curve of the fiber coiling process 1 plus the polarization-maintaining welding point 1 of the polarization-maintaining optical path component of the present invention.

[0049] Figure 6 This is a test curve of the fiber coiling process 2 plus the polarization-maintaining welding point 2 of the polarization-maintaining optical path component of the present invention.

[0050] Figure 7 This is a flow chart for evaluating the indicators of polarization-maintaining optical path components of the present invention. DETAILED DESCRIPTION

[0051] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0052] like Figure 1 As shown, a temperature test and evaluation system for polarization-maintaining optical path components of a fiber optic gyroscope includes an optical path part, a circuit part, and a test device; the optical path part includes an erbium-doped fiber light source 1, a fiber coupler 2, a polarization-maintaining optical path component 3, including an optical fiber ring, a Y-waveguide integrated optical device, a polarization-maintaining optical fiber pigtail and a polarization-maintaining fusion point, and a detector 4; the circuit part includes a temperature sensor 5, a light source driving circuit 6, and a digital circuit 7. The test equipment includes a test fixture 8, a test cable 9, a power supply box 10, an evaluation unit 11, and a temperature box 12; before improvement: the optical fiber ring is placed in the temperature box alone, and after improvement, the entire polarization-maintaining optical path component consisting of the optical fiber ring, the Y-waveguide integrated optical device, the polarization-maintaining optical fiber pigtail and the polarization-maintaining fusion point is placed in the temperature box. From the perspective of the optical path, the optical fiber ring is a component for two-phase light wave propagation, and the polarization-maintaining optical path component is a component for splitting light into two beams of light, two-phase light wave propagation, and then combining the two beams of light. It is the entire interference optical path, including polarization of light, polarization light maintenance, and interference of light, and is more complete.

[0053] Optical fibers are used to fuse the optical path parts, and detectors and wires are used to connect the optical path and the circuit part. The test cable connects the circuit part, power box, and computer to complete the electrical connection of the test system.

[0054] The photoelectric signal flow of the test system is as follows: the erbium-doped fiber light source 1 provides a driving current through the light source driving circuit 6 to generate an optical signal i1, and the optical signal i1 is split by the optical fiber coupler 2 to form an optical signal i2. The optical signal i2 reaches the Y waveguide and generates two beams of linear polarized light after polarization and splitting. The two beams of linear polarized light pass through the polarization-maintaining pigtail and the polarization-maintaining fusion point between the Y waveguide and the optical fiber ring in turn, and then enter the optical fiber ring; after propagating through the optical fiber ring, the two beams of linear polarized light are reversed and then pass through the polarization-maintaining pigtail and the polarization-maintaining fusion point between the Y waveguide and the optical fiber ring in turn, and then reach the Y waveguide to combine and form an optical signal i3 carrying rotation speed information; the interference signal i3 is split again by the optical fiber coupler 2 to form an optical signal i4 and reaches the detector 4, and the detector 4 converts the received optical signal i4 into an electrical signal; the electrical signal is resolved by the digital circuit 7 to form three signals: angular velocity signal y1, modulation signal y2, and gain error signal y3; the digital circuit 7 is processed by the front-end signal The invention is composed of a circuit, a digital signal processing logic chip and a back-end signal processing circuit; wherein the front-end signal processing circuit includes a filtering circuit, a first amplifying circuit and an analog-to-digital converter; the back-end signal processing circuit includes a first digital-to-analog converter, a second amplifying circuit, a switching switch, a second digital-to-analog converter and a third amplifying circuit; the angular velocity signal y1 represents the signal of the gyroscope sensitive to the external angular velocity and is output externally; the modulation signal y2 is used as a feedback signal to compensate the Y waveguide to form a first closed-loop feedback loop; the gain error signal y3 is used as a feedback signal to compensate the first digital-to-analog converter to form a second closed-loop feedback loop to compensate for the gain error caused by the half-wave voltage change of the Y waveguide; the temperature sensor 5 packages the measured fiber ring temperature information with the output angular velocity signal y1 of the gyroscope to form gyroscope data and uploads them together to the evaluation unit 11; the evaluation unit 11 obtains the evaluation index according to the angular velocity signal y1 and the temperature information of the gyroscope.

[0055] In order to avoid the influence of other light, circuit components and temperature chamber on the test of polarization-maintaining optical path components, certain requirements are put forward for the test accuracy at room temperature and constant temperature point:

[0056] Test at room temperature, power on for 3 hours, test the curve of polarization-maintaining optical path components as follows Figure 2 , using the data from the last two hours, the bias stability is calculated to be 0.0017° / h (100s, 1σ), which reflects the room temperature noise level of the gyro circuit and optical path.

[0057] Constant temperature point test, the temperature box is set to constant temperature -40℃ and +60℃ respectively, powered on for 3 hours, and the curve of the polarization-maintaining optical path component is as follows Figure 3 , Figure 4 Using the data from the last two hours, the zero bias stability is calculated to be 0.0038° / h (100s, 1σ) and 0.0025° / h (100s, 1σ), which reflects the low high temperature noise level of the gyro circuit and optical path, and also reflects the vibration resistance of the temperature box.

[0058] After the above two tests meet the accuracy indicators, there is no need to test again.

[0059] Full temperature test, set temperature range: -40℃~+60℃, temperature change rate: 1℃ / min, high and low temperature holding time 3 hours. Test curve of polarization-maintaining optical path components as follows Figure 5 , Figure 6 The fiber ring and Y-waveguide integrated optical devices remain unchanged, but the fiber pigtail coiling process and fusion point are changed. Figure 5 This is the test curve of the polarization-maintaining optical path component fiber coiling process 1 plus polarization-maintaining welding point 1. The temperature range is calculated to be 0.3° / h and the zero bias stability after compensation is 0.018° / h (100s, 1σ). Figure 6 This is the test curve of the polarization-maintaining optical path component fiber coiling process 2 plus polarization-maintaining welding point 2. The calculated temperature range is 0.18° / h and the zero bias stability after compensation is 0.007° / h (100s, 1σ). Figure 5 and Figure 6 It can be seen that by changing the fiber coiling process and the polarization-maintaining welding point, the full temperature range of the polarization-maintaining optical path component is reduced from 0.3° / h to 0.18° / h, reduced to 60%, and the zero bias stability after compensation is reduced from 0.018° / h (100s, 1σ) to 0.007° / h (100s, 1σ), and the accuracy is improved by 2.6 times. Only by testing the entire polarization-maintaining optical path component can the influence of the fiber coiling process and the polarization-maintaining welding point be measured.

[0060] The evaluation indicators in the evaluation system include the temperature range and the standard deviation after compensation under the temperature test of the polarization-maintaining optical path component. The temperature range represents the temperature sensitivity of the polarization-maintaining optical path component. The larger the value, the poorer the symmetry of the temperature range. The standard deviation after compensation represents the accuracy level of the polarization-maintaining optical path component after compensation. The larger the value, the poorer the accuracy of the fiber optic gyroscope after compensation. The smaller the requirements for the two indicators, the better. The quality of the polarization-maintaining optical path component can be judged by these two indicators.

[0061] The test temperature conditions for polarization-maintaining optical path components are consistent with the test conditions after the gyro is assembled.

[0062] The temperature extreme difference reflects the symmetry of the polarization-maintaining optical path component. The larger the value, the greater the temperature sensitivity of the polarization-maintaining optical path component. The size of the compensated standard deviation reflects the accuracy level of the polarization-maintaining optical path component after compensation. The larger the value, the poorer the accuracy of the fiber optic gyro after compensation. The specific calculation process is as follows: Figure 7 .

[0063] The evaluation system includes a data loading module, a parameter selection and parameter setting module, a data processing module, a result display module and a graphic display module.

[0064] The data loading module loads and displays the number of rows and columns of gyro data. The content of gyro data includes the output angular velocity and temperature of the gyro.

[0065] The Select Parameters and Parameter Settings module displays the start and end rows of the gyro data, and the number of columns in the data file where the gyro data is located. In the Select Parameters and Parameter Settings module, set the data sampling frequency, smoothing time, and scale factor. The default data start row is 1, the end row is the total length of the data, and the gyro data is located in the second column. The sampling frequency is 1Hz, the smoothing time is 100s, and the scale factor is the ratio of the data average to the ground speed. Users can change any of these parameters according to actual conditions.

[0066] The data processing module calculates the evaluation index according to the output angular velocity and temperature of the gyroscope, and transmits the evaluation index to the result display module or the graphic display module;

[0067] The result display module displays the extreme temperature difference of the polarization-maintaining optical path components, the standard deviation results after compensation, the zero bias value, and the zero bias stability results before and after compensation;

[0068] The graphic display module displays a curve showing the change of the zero bias value of the polarization-maintaining optical path component before compensation with time, or displays a comparison curve showing the change of the zero bias value of the polarization-maintaining optical path component before and after compensation with time; at the same time, the graphic display module outputs a Figure graphic of Matlab.

[0069] The method for evaluating the polarization-maintaining optical path component of a fiber optic gyroscope using the temperature testing and evaluation system for the polarization-maintaining optical path component of the fiber optic gyroscope comprises the following steps:

[0070] Test the accuracy of the normal temperature and constant temperature points of the test and evaluation system to ensure that the accuracy index is met;

[0071] Set the temperature range, temperature change rate, high and low temperature holding time of the incubator, and collect and save the gyro data of the polarization-maintaining optical path components;

[0072] Use the evaluation system to load the gyro data, and set the data sampling frequency, smoothing time and scale factor in the evaluation system;

[0073] In the evaluation system, the temperature extremes of the polarization-maintaining optical path components, the standard deviation results after compensation, the zero bias value, the zero bias stability results before and after compensation are obtained, and the curve of the zero bias value of the polarization-maintaining optical path components changing with time, the comparison curve of the zero bias value of the polarization-maintaining optical path components changing with time before and after compensation are displayed. At the same time, a Figure graph of the zero bias value of the polarization-maintaining optical path components changing with time is obtained.

[0074] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A temperature test and evaluation system for polarization-maintaining optical path components of a fiber optic gyroscope, characterized in that: The invention comprises an erbium-doped optical fiber light source (1), an optical fiber coupler (2), a polarization-maintaining optical path component (3), a detector (4), a temperature sensor (5), a light source driving circuit (6) and a digital circuit (7), a test fixture (8), a test cable (9), an evaluation unit (11) and a temperature box (12); wherein the polarization-maintaining optical path component (3) comprises a Y waveguide and an optical fiber ring; one side of the Y waveguide is provided with two sections of polarization-maintaining pigtails, and the optical fiber ring is provided with two sections of polarization-maintaining pigtails; a closed loop is formed by fusing the two sections of polarization-maintaining pigtails; the fusion point between the polarization-maintaining pigtails is called a polarization-maintaining fusion point; the optical fiber ring is placed in the test fixture (8), the temperature sensor (5) is placed at the center of the optical fiber ring coil, and the test fixture (8) is placed in a temperature box (12) with a vibration-isolating foundation; the light source driving circuit (6), the digital circuit (7), the power supply box (10) and the evaluation unit (11) are electrically connected through a three-port test cable (9); The erbium-doped optical fiber light source (1) generates an optical signal i1 by providing a driving current through a light source driving circuit (6). The optical signal i1 is split by an optical fiber coupler (2) to form an optical signal i2. The optical signal i2 reaches a Y waveguide and generates two beams of linearly polarized light after polarization and splitting. The two beams of linearly polarized light sequentially pass through a polarization-maintaining pigtail and a polarization-maintaining fusion point between the Y waveguide and the optical fiber ring and enter the optical fiber ring. After propagating through the optical fiber ring, the two beams of linearly polarized light reversely pass through a polarization-maintaining pigtail and a polarization-maintaining fusion point between the Y waveguide and the optical fiber ring and arrive at the Y waveguide to combine and form an optical signal i3 carrying rotation speed information. The interference signal i3 is split again by an optical fiber coupler (2) to form an optical signal i4 and reaches a detector (4). The detector (4) converts the received optical signal i4 into an electrical signal. The electrical signal is resolved by a digital circuit (7) to form three signals: an angular velocity signal y1, a modulation signal y2, and a gain error signal y3. The digital circuit (7) is composed of a front-end signal processing circuit. , a digital signal processing logic chip and a back-end signal processing circuit; wherein the front-end signal processing circuit comprises a filtering circuit, a first amplifying circuit and an analog-to-digital converter; the back-end signal processing circuit comprises a first digital-to-analog converter, a second amplifying circuit, a switching switch, a second digital-to-analog converter and a third amplifying circuit; the angular velocity signal y1 represents a signal of the gyroscope sensitive to external angular velocity and is output externally; the modulation signal y2 is used as a feedback signal to compensate the Y waveguide to form a first closed-loop feedback loop; the gain error signal y3 is used as a feedback signal to compensate the first digital-to-analog converter to form a second closed-loop feedback loop to compensate for the gain error caused by the half-wave voltage change of the Y waveguide; the temperature sensor (5) packages the measured fiber ring temperature information with the output angular velocity signal y1 of the gyroscope to form gyroscope data and uploads them together to the evaluation unit (11); the evaluation unit (11) obtains an evaluation index according to the angular velocity signal y1 and the temperature information of the gyroscope.

2. A temperature testing and evaluation system for a fiber optic gyroscope polarization-maintaining optical path component according to claim 1, characterized in that: The polarization-maintaining fusion point loss is no more than 0.1dB, and the crosstalk value is no less than 35dB; the polarization-maintaining pigtails of the optical fiber ring and the Y-waveguide are coiled in a preset path, and during the coiling process, the optical fiber is ensured to have no twisting, no squeezing, and no hanging.

3. A temperature testing and evaluation system for a fiber optic gyroscope polarization-maintaining optical path component according to claim 1, characterized in that: The evaluation index comprises a range and a compensated standard deviation of the polarization-maintaining optical path component (3) under temperature testing; the range is used to judge the temperature sensitivity of the polarization-maintaining optical path component (3), and the compensated standard deviation is used to judge the accuracy level of the polarization-maintaining optical path component (3) after compensation.

4. A temperature testing and evaluation system for a fiber optic gyroscope polarization-maintaining optical path component according to claim 3, characterized in that: The calculation method of the range of the polarization-maintaining optical path component is: firstly, the original data is smoothed for 100 seconds, then the smoothed data is slide-smoothed for 10 seconds, and finally, the maximum value and the minimum value of the slide-smoothed data are found and subtracted to obtain the range.

5. A temperature testing and evaluation system for a fiber optic gyroscope polarization-maintaining optical path component according to claim 4, characterized in that: The specific calculation process of the extreme difference of the polarization-maintaining optical path component is: Assuming that the original output angular velocity data of the polarization-maintaining optical path component (3) is B and the sampling time is t, the data after 100s smoothing is: Among them, i represents the number of data, Represents the total number of data collected within 100 seconds; mean() represents the average value of all the data in the brackets; The data after 100s smoothing is subjected to 10s sliding smoothing to obtain a smoother curve. The data after 10s smoothing is in, Represents the total number of data collected within 10s; Subtract the maximum and minimum values ​​in the smoother curve to obtain the temperature range.

6. A temperature testing and evaluation system for polarization-maintaining optical path components of an optical fiber gyroscope according to claim 5, characterized in that: Before collecting the angular velocity data of the polarization-maintaining optical path component (3), the polarization-maintaining optical path component (3) is placed in an incubator (12), and the temperature of the incubator (12) is set to -40°C and maintained for 3 hours, then raised to 60°C at a temperature change rate of 1°C / min and maintained for another 3 hours.

7. A temperature testing and evaluation system for a fiber optic gyroscope polarization-maintaining optical path component according to claim 4, characterized in that: The calculation method of the standard deviation of the polarization-maintaining optical path component after compensation is: Assume the original output angular velocity data is B, the sampling time is t, and the temperature information is T; Using the ratio of the temperature difference before and after to the time As the temperature change rate; where T is the temperature information, t is the sampling time, and Δt is the time interval; Assume that the derived signal T based on temperature information, T 2 , T 3 , ..., respectively x1, x2, ..., x m ; Suppose x1,x2,…,x m variables, the multiple linear regression model is expressed as B=β0+β1x1+β2x2++β m x m +e where β0,β1,β m There are m+1 unknowns. If n sets of observation data are obtained, the linear regression model is Written in matrix form: in The unknowns of the multivariate linear regression equation are usually estimated by least squares. The sample regression model under ordinary least squares method is The output angular velocity data after compensation is Seek Standard Deviation As the standard deviation after compensation of polarization-maintaining optical path components.

8. A temperature testing and evaluation system for a fiber optic gyroscope polarization-maintaining optical path component according to claim 7, characterized in that: Before collecting the angular velocity and temperature data of the polarization-maintaining optical path component (3), the polarization-maintaining optical path component (3) is placed in an incubator (12), and the temperature of the incubator (12) is set to -40°C and maintained for 3 hours, then raised to 60°C at a temperature change rate of 1°C / min and maintained for another 3 hours.

9. The method for evaluating a polarization-maintaining optical path component of a fiber optic gyroscope according to claim 3, characterized in that: Before starting the test, the system is also tested before the experiment, including: Power on at room temperature for 3 hours, obtain the compensated standard deviation of the polarization-maintaining optical path component (3) and the temperature-time curve, and use the data of the last 2 hours. If the compensated standard deviation is not greater than 0.05° / h, it is considered that the system is normal and the test data is available; The temperature box (12) is set to a constant temperature of -40°C and +60°C, and powered on for 3 hours at the two temperatures, respectively, to obtain the compensated standard deviation of the polarization-maintaining optical path component and the temperature-time variation curve. The data of the last 2 hours are used. If the compensated standard deviation is not greater than 0.05° / h, it is considered that the system is normal and the test data is available.

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