A fiber-optic gyroscope test system

Abstract

The application relates to a fiber-optic gyroscope testing system. The system comprises a light source, a coupler with at least four end heads, a sensitive light path, a reference light path, a subtracter, an A / D module, an FPGA, a D / A module and a waveguide driver connected in sequence; the light emitted by the light source is divided into two paths by the coupler and then enters the sensitive light path and the reference light path respectively; the sensitive light path comprises photoelectric modulators, a sensitive fiber-optic ring, a coupler, a first photoelectric detector and a first preamplifier connected in sequence; the output end of the waveguide driver is in communication connection with the photoelectric modulators; the reference light path comprises a reference fiber-optic ring, a second photoelectric detector and a second preamplifier connected in sequence, and a compensation fiber with a preset length is connected in the reference light path, so that the optical paths of the sensitive light path and the reference light path are equal; the output ends of the first preamplifier and the second preamplifier are connected with the input ends of the subtracter respectively; the subtracter is used for subtracting the signal output by the first preamplifier from the signal output by the second preamplifier, so as to obtain a photoelectric signal with noise removed. The application can remove light source intensity noise and improve rotation speed demodulation precision.

Description

Technical Field

[0001] This invention relates to the field of fiber optic gyroscope technology, and in particular to a fiber optic gyroscope testing system. Background Technology

[0002] Fiber optic gyroscopes, with their all-solid-state, high reliability, and high precision, are particularly suitable for space applications. Currently used fiber optic gyroscopes mostly have an accuracy of 0.01° / h to 0.1° / h. Ultra-high precision micrometer sensors used for space micro-vibration measurement place even higher demands on the accuracy of fiber optic gyroscopes, requiring zero-bias stability of 0.0005° / h and a random walk coefficient of 0.00008° / √h, while maintaining a sampling frequency of 500Hz. Furthermore, the increased bandwidth means that the sensor cannot reduce noise through filtering; measures must be taken to suppress noise at its source. Theoretical analysis reveals that ASE light source intensity noise accounts for over 50% of the noise sources in fiber optic gyroscope micrometer sensors, which is the main reason for the low measurement accuracy of existing fiber optic gyroscope testing systems.

[0003] Therefore, there is an urgent need for a fiber optic gyroscope testing system that can remove light source intensity noise to solve the above problems. Summary of the Invention

[0004] This invention provides a fiber optic gyroscope testing system that can eliminate light source intensity noise and improve rotation speed demodulation accuracy.

[0005] In a first aspect, embodiments of the present invention provide a fiber optic gyroscope testing system, comprising:

[0006] The system comprises a light source, a coupler with at least four ends, a sensitive optical path, a reference optical path, a subtractor, an A / D module, an FPGA, a D / A module, and a waveguide driver connected in sequence; the light emitted from the light source is split into two paths by the coupler and then enters the sensitive optical path and the reference optical path respectively.

[0007] The sensitive optical path includes a photoelectric modulator, a sensitive fiber optic ring, the coupler, a first photodetector, and a first preamplifier connected in sequence; the output terminal of the waveguide driver is communicatively connected to the photoelectric modulator.

[0008] The reference optical path includes a reference fiber ring, a second photodetector, and a second preamplifier connected in sequence, and a compensation fiber of a preset length is connected in the reference optical path to make the optical path of the sensitive optical path and the reference optical path equal.

[0009] The output terminals of the first preamplifier and the second preamplifier are respectively connected to the input terminal of the subtractor; the subtractor is used to subtract the signal output by the first preamplifier from the signal output by the second preamplifier to obtain a noise-removed photoelectric signal.

[0010] This invention provides a fiber optic gyroscope testing system. In this system, the light from both the sensitive and reference optical paths originates from the same source. The sensitive signal includes both rotational speed information and noise information, while the reference signal only includes noise information. Therefore, by splicing a compensation fiber of a predetermined length into the reference optical path, the optical path lengths of the sensitive and reference optical paths can be made equal, resulting in identical signal delays. This ensures that the noise contained in the two light wave signals arriving at the subtractor is the same. Finally, by subtracting the signals output from the two preamplifiers using the subtractor, the noise in the sensitive signal can be cancelled, improving the speed demodulation accuracy. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of a fiber optic gyroscope testing system provided in an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of a traditional fiber optic ring.

[0014] Figure 3 This is a schematic diagram of the integrated fiber optic ring of the present invention;

[0015] Figure 4 This is a schematic diagram of the correlation curves between the sensitive signal and the reference signal before compensation of the reference optical path;

[0016] Figure 5 This is a schematic diagram of the correlation curves between the sensitive signal and the reference signal after the reference optical path has been compensated using the method of this application;

[0017] Figure 6 This is a schematic diagram comparing the noise reduction effect before and after noise removal using the method of this application;

[0018] Figure 7 This is a schematic diagram of a finite element simulation model of an optoelectronic modulator provided in an embodiment of the present invention;

[0019] Figure 8This is a schematic diagram showing the variation of the longitudinal RC parameters of the modulator with the electrode width.

[0020] Figure 9 Curves showing the variation of the modulator's transverse RC parameters with electrode width for different electrode spacings;

[0021] Figure 10 A schematic diagram of the drift process of the effectively modulated electrical signal under different electrode parameters;

[0022] Figure 11 A schematic diagram showing the change in drift of an effectively modulated electrical signal as a function of electrode width. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Please refer to Figure 1 This invention provides a fiber optic gyroscope testing system, comprising:

[0025] The system comprises a light source, a coupler with at least four ends, a sensitive optical path, a reference optical path, a subtractor, an A / D module, an FPGA, a D / A module, and a waveguide driver connected in sequence; the light emitted from the light source is split into two paths by the coupler and then enters the sensitive optical path and the reference optical path respectively.

[0026] The sensitive optical path includes a photoelectric modulator, a sensitive fiber optic ring, the coupler, a first photodetector, and a first preamplifier connected in sequence; the output terminal of the waveguide driver is communicatively connected to the photoelectric modulator.

[0027] The reference optical path includes a reference fiber ring, a second photodetector, and a second preamplifier connected in sequence, and a compensation fiber of a preset length is connected in the reference optical path to make the optical path of the sensitive optical path and the reference optical path equal.

[0028] The output terminals of the first preamplifier and the second preamplifier are respectively connected to the input terminal of the subtractor; the subtractor is used to subtract the signal output by the first preamplifier from the signal output by the second preamplifier to obtain a noise-removed photoelectric signal.

[0029] In this system, both the sensitive and reference optical paths originate from the same light source. The sensitive signal includes both rotational speed and noise information, while the reference signal only contains noise information. Therefore, by splicing a compensation fiber of a predetermined length into the reference optical path, the optical path lengths of the sensitive and reference optical paths are made equal, resulting in identical signal delays. This ensures that the noise contained in the two light waves arriving at the subtractor is the same. Finally, by subtracting the signals output from the two preamplifiers using the subtractor, the noise in the sensitive signal is canceled out, improving the speed demodulation accuracy.

[0030] It should be noted that the aforementioned fiber optic gyroscope testing system can be applied to newly built systems or to the upgrading and transformation of existing systems. When applied to the upgrading and transformation of existing systems, a reference optical path and a subtractor need to be added to the traditional testing system, and the new equipment needs to be connected and configured according to the system described in this application.

[0031] The specific structure of the fiber optic gyroscope testing system of this application is described in detail below.

[0032] like Figure 1 As shown, the light source is an ASE light source, and the coupler is preferably a 2×2 coupler. The light emitted by the ASE light source is split into two paths after passing through the coupler. One path enters the photoelectric modulator and the sensitive fiber ring, where the angular velocity information is detected. Then, it passes back through the photoelectric modulator and coupler and is output to the first photodetector. The other path enters the reference fiber ring and is output from the reference fiber ring to the second photodetector. The two signals are respectively preamplified and then enter a subtractor. After processing by the subtractor, the noise in the sensitive signal is canceled, and only the angular velocity information is retained. Then, the angular velocity information is output after being processed by the detection circuit consisting of an A / D module, an FPGA, a D / A module, and a waveguide driver.

[0033] It should be noted that before the compensation fiber is connected, the difference in length between the two loops and the optical path introduced by other components in the optical path will cause a delay between the sensitive signal and the reference signal. At this time, the noise in the two signals is inconsistent and cannot be canceled. Therefore, a compensation fiber is required.

[0034] In some implementations, the length of the compensation fiber is determined in the following manner:

[0035] Construct an initial gyroscope test system that does not include compensation fiber;

[0036] Based on the two channels of the multi-channel acquisition system, the output signals of the first photodetector and the second photodetector in the initial gyroscope test system are acquired according to the set sampling rate to obtain two time sequence signals;

[0037] The correlation between two time-series signals is calculated to obtain a cross-correlation sequence.

[0038] The delay between the sensitive signal and the reference signal is determined based on the cross-correlation sequence.

[0039] The optical path difference between the sensitive signal and the reference signal is determined based on the delay.

[0040] The length of the compensation fiber is determined based on the optical path difference.

[0041] In some implementations, the cross-correlation sequence between two time-series signals is calculated using the following formula:

[0042]

[0043] In the formula, x and y are the signal sequences output by the first photodetector and the second photodetector, respectively, and the length of each sequence is N, n = 0 to N; R xy (m) represents the correlation coefficient of x and y at point m, where m = -N to N.

[0044] Furthermore, for statistical purposes, the cross-correlation sequence can be shifted to obtain a cross-correlation sequence C(J) where all sampling points are greater than 0:

[0045] C(J)=R xy (JN)J=1,2,…,2N-1

[0046] The translated cross-correlation sequence is as follows Figure 4 and Figure 5 As shown in the figure, if there is no delay between the two signals, the maximum value of the cross-correlation sequence should be at the center point, i.e., J = N; if J ≠ N, it indicates that there is a delay between the two signals.

[0047] Furthermore, the length of the compensation fiber, which is the time difference between the two signals, can be calculated using the correlation between the two signals. If the delays of the two signals are the same, the sampling point with the highest correlation should appear at the midpoint of the cross-correlation curve after cross-correlation calculation; if the delays are different, the time difference can be calculated based on the distance between the maximum value point and the midpoint of the cross-correlation curve, and thus the length of the compensation fiber can be determined.

[0048] The determination of the delay between the sensitive signal and the reference signal based on the cross-correlation sequence includes:

[0049] Determine the sampling location of the sampling point with the highest correlation in the cross-correlation sequence;

[0050] Calculate the distance difference between the sampling location and the location of the central sampling point;

[0051] The delay between the sensitive signal and the reference signal is determined based on the distance difference and the sampling rate.

[0052] In some implementations, the delay between the sensitive signal and the reference signal is calculated using the following formula:

[0053]

[0054] In the formula, T is the delay between the sensitive signal and the reference signal; N is the distance difference between the sampling position of the sampling point with the highest correlation and the position of the center sampling point; and f is the sampling rate.

[0055] In some implementations, the optical path difference between the sensitive signal and the reference signal is calculated using the following formula:

[0056] S = cT

[0057] In the formula, S is the optical path difference between the sensitive signal and the reference signal; c is the speed of light in a vacuum.

[0058] In some implementations, the length of the compensation fiber is calculated using the following formula:

[0059]

[0060] In the formula, L is the length of the compensation fiber; r is the refractive index of the compensation fiber.

[0061] In some embodiments, a compensation fiber of a predetermined length is fused to the fiber between the reference fiber loop and the second photodetector.

[0062] In some embodiments, the sensitive fiber ring and the reference fiber ring are of equal length and are wrapped around the same fiber ring;

[0063] The reference fiber ring functions as both a pad fiber ring and a reference optical transmission ring, and both the sensitive fiber ring and the reference fiber ring have two pigtails.

[0064] like Figure 2 The diagram shows a schematic of a traditional fiber optic ring. In addition to the sensitive fiber ring, it also includes a thin layer of fiber padding for stress buffering and thermal stress release, ensuring structural stability. Figure 3 The diagram shows the integrated optical fiber of this application. In the diagram, the reference fiber ring replaces the original pad fiber ring, which not only provides protection but also serves as the optical path for the reference signal. Thus, by adopting an integrated design, the delay difference caused by temperature inconsistencies and the intensity difference caused by inconsistent radiation loss between the sensitive fiber ring and the reference fiber ring can be further reduced, improving the intensity noise cancellation effect during long-term use in space environments.

[0065] To demonstrate the noise reduction effect of this application, the inventors used the following parameters for verification:

[0066] The sampling frequency of the acquisition system was set to 2.5 G / s, and the number of sampling points for each detector was 100,000. Under the initial fiber reference fiber length (i.e., without the compensation fiber connected), the correlation curves of the sensitive signal and the reference signal output by the two detectors are shown in the diagram below. Figure 4 As shown:

[0067] As shown in the graph, the point with the highest correlation is point 96432, which is N = 3568 points away from the center point 100000. Based on a sampling rate of 2.5 G / s, the time delay between the two signals is:

[0068]

[0069] Considering the speed of light c is 3 × 10 8 From m / s, the optical path difference S between the two signals can be calculated to be 428.16m.

[0070] Given that the refractive index r of the delay-compensating fiber is 1.45, the length of the compensation fiber is 295.28m.

[0071] The calculated compensation fiber was spliced ​​into the test system of this application, and the correlation curves of the sensitive signal and reference signal output by the two detectors were recalculated. The results are as follows: Figure 5 As shown in the figure, after adjustment, the maximum correlation point is located at the midpoint of the sequence, and the maximum correlation value is 0.93265, indicating that the delay between the two signals is basically zero. Figure 6 The diagram shows a comparison of system noise before and after noise cancellation. As can be seen from the diagram, the method of this application can significantly remove light source noise.

[0072] In addition, the optical path difference error L between the two signals determined using the method of this application error The maximum value can be calculated using the following formula:

[0073]

[0074] Optical path difference error is the distance light travels within half the system sampling period. Based on the actual sampling rate of 2.5 Gbps, the maximum optical path difference between the sensitive signal and the reference signal after delay fiber compensation in this application will not exceed 5 cm. Therefore, the method in this application can precisely adjust the time delay between the sensitive signal and the reference signal, ensuring good intensity noise cancellation.

[0075] Furthermore, the inventors discovered that the reset error of the fiber optic gyroscope is also a key factor affecting the speed adjustment accuracy, and that the reset error is mainly related to the electrode parameters of the photoelectric modulator. Based on this, the inventors propose the following method to improve the electrode parameters of the photoelectric modulator:

[0076] Step 100: Construct a finite element simulation model of the optoelectronic modulator; the simulation model includes equivalent transverse resistance and capacitance and equivalent longitudinal resistance and capacitance.

[0077] Step 102: Based on the simulation model, calculate the equivalent resistance and capacitance parameters of the optoelectronic modulator under different electrode parameters to obtain multiple sets of equivalent resistance and capacitance parameters; the electrode parameters include electrode width and electrode spacing.

[0078] Step 104: Based on each set of equivalent resistance and capacitance parameters, determine the quantitative relationship between the drift time and drift amount of the effective modulated electrical signal on the optoelectronic modulator and the electrode parameters;

[0079] Step 106: Based on the quantitative relationship, determine the final electrode parameters of the photoelectric modulator under the set requirements; the set requirements include setting the drift amount and setting the drift time.

[0080] In this embodiment, by constructing a finite element simulation model of the optoelectronic modulator, the transient phase response of the modulator under the action of a step signal can be obtained, and the relationship between the effective modulation signal drift time and drift amount and the electrode parameters can be quantitatively determined. Thus, once the required set drift amount and set drift time are determined, the electrode parameters can be determined based on this quantitative relationship. By adjusting the electrode parameters, the RC network model parameters and modulation electric field distribution characteristics can be changed, altering the transient phase response characteristics of the modulator, suppressing the phase drift degree of the modulator, thereby reducing the gyroscope's reset error, reducing detection noise, and improving the speed adjustment accuracy of the fiber optic gyroscope.

[0081] First, regarding step 100:

[0082] like Figure 7 The figure shows a finite element simulation model of an optoelectronic modulator. As can be seen from the figure, the model includes an equivalent lateral resistor-capacitor (RC) and equivalent longitudinal resistors-capacitors (RCs) positioned on either side of the equivalent lateral RC. The equivalent lateral RC includes a lateral resistance R1 and a lateral capacitance C1, and each equivalent longitudinal RC includes a longitudinal resistance R2 and a longitudinal capacitance C2. The parallel RC groups represent the charge storage, conduction, and injection capabilities of different regions within the modulator. The stepped wave signal applied to the modulator can be considered as a step signal within the time period of each step. Figure 7 As shown, when the photoelectric modulator is subjected to a unit step signal V m (t) During modulation, the effective modulation electrical signal applied to the transverse resistor-capacitor junctions on both sides of the optical transmission channel is V. mt (t).

[0083] For step 102, the following are included:

[0084] Determine the lithium niobate crystal parameters of the optoelectronic modulator;

[0085] Set multiple different sets of electrode parameters;

[0086] The electrode parameters are iterated over. For each set of electrode parameters encountered, the following steps are performed: the set of electrode parameters and the lithium niobate crystal parameters are used as input to perform electric field distribution simulation calculation on the simulation model to obtain the equivalent resistance and capacitance parameters under the set of electrode parameters; this process is repeated until all electrode parameters are traversed to obtain multiple sets of equivalent resistance and capacitance parameters.

[0087] In this step, the electrode parameters for each group can be determined according to the simulation requirements. For example... Figure 8 The figure shows the variation curves of longitudinal resistance R2 and longitudinal capacitance C2 for different electrode widths. It can be seen from the figure that the modulator can be equivalent to a combination of a large resistor and a small capacitor, with its longitudinal equivalent resistance R2 on the order of tens of TΩ and its longitudinal equivalent capacitance C2 on the order of tens of pF. Furthermore, as the electrode width increases, the longitudinal resistance gradually decreases, while the longitudinal capacitance increases approximately linearly.

[0088] like Figure 9 As shown, the transverse resistance and capacitance parameters vary with the electrode width W. e The graph shows the variation curves. As can be seen from the graph, the lateral resistance R1 is almost linearly proportional to the electrode width, with a value in the hundreds of TΩ range, nearly an order of magnitude larger than the longitudinal resistance R2. This ensures that most of the voltage division of the modulated signal applied to the modulator is distributed across the optical transmission channel, guaranteeing high modulation efficiency. The lateral capacitance C1 gradually decreases with increasing electrode width, and its value is an order of magnitude smaller than the longitudinal capacitance C2. Compared to the electrode width, the electrode spacing has a smaller impact on the lateral resistance and capacitance parameters.

[0089] For step 104, the following are included:

[0090] Based on the simulation model, the calculation formula for the effective modulation electrical signal loaded on both sides of the optical transmission channel when the optoelectronic modulator is modulated by a unit step signal is determined; the calculation formula consists of the steady-state part and the voltage drift part of the effective modulation electrical signal.

[0091] Substitute each set of equivalent resistance and capacitance parameters into the calculation formula to obtain the corresponding drift time and DC drift amount;

[0092] The variation curves of drift time, DC drift amount and electrode parameters are calculated to obtain the quantitative relationship between the drift time and drift amount of the effective modulated electrical signal and the electrode parameters.

[0093] In this step, the formula for calculating the effective modulated electrical signal is:

[0094] V mt (t)=V1+V2(t)

[0095]

[0096] In the formula, V mt V(t) represents the effective modulated electrical signal applied to both sides of the optical transmission channel; V1 and V2(t) represent the steady-state part and voltage drift part of the effective modulated electrical signal, respectively; R1 and C1 are the transverse resistance and transverse capacitance of the optoelectronic modulator, respectively; R2 and C2 are the longitudinal resistance and longitudinal capacitance of the optoelectronic modulator, respectively; τ is a time constant, which characterizes the drift time required for the signal to reach a steady state.

[0097] In the above formula, the effective modulated electrical signal V mt The equation (t) consists of two parts. The first part is the steady-state value V1, which determines the modulation efficiency of the modulator. The second part is the voltage drift caused by capacitors C1 and C2, where τ is a time constant, representing the time required for the signal to reach a steady state, and is an important cause of DC drift in the modulator. By changing the equivalent capacitances C1 and C2 of the modulator, the voltage drift amplitude in the above equation can be changed, thus suppressing the DC drift phenomenon of the modulator.

[0098] By substituting each set of equivalent resistance and capacitance parameters into the voltage drift section using the above calculation formula, the DC drift amount and drift time of the signal can be obtained.

[0099] Based on the calculated data, the drift process curves of the effectively modulated electrical signal with different electrode widths can be plotted, such as... Figure 10 As shown in the figure, the electrode width has a more significant impact on the drift of the electrical signal. As the electrode width increases, the amplitude of the electrical signal drift gradually decreases, while the difference in the settling time is not significant.

[0100] In addition, the effective modulation of the electrical signal drift change ΔV over 1 second is used. drift The ratio of the voltage to the steady-state voltage Vs characterizes the amount of drift in the electrical signal, and this drift varies with the electrode width as follows: Figure 11 As shown in the figure. It can be seen from the figure that a larger electrode spacing G... e The electrical signal drift corresponding to the electrode width is smaller, and the effect of electrode width is greater. For example, increasing the electrode width from the conventional 20μm to 25μm can reduce the change in electrical signal drift by about 35% per second.

[0101] Finally, regarding step 106:

[0102] Once the quantitative relationship between drift amount, drift time, and electrode parameters is established, it is only necessary to determine the set drift amount and set drift time according to actual needs. Then, the electrode spacing and width can be determined based on this quantitative relationship, yielding the optimal electrode parameters. By using these optimal electrode parameters, the distribution characteristics of the modulation electric field can be improved, and the gyroscope's reset error can be suppressed.

[0103] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0104] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fiber optic gyroscope testing system, characterized in that, include: The system comprises a light source, a coupler with at least four ends, a sensitive optical path, a reference optical path, a subtractor, an A / D module, an FPGA, a D / A module, and a waveguide driver connected in sequence; the light emitted from the light source is split into two paths by the coupler and then enters the sensitive optical path and the reference optical path respectively. The sensitive optical path includes a photoelectric modulator, a sensitive fiber optic ring, the coupler, a first photodetector, and a first preamplifier connected in sequence; the output terminal of the waveguide driver is communicatively connected to the photoelectric modulator. The reference optical path includes a reference fiber ring, a second photodetector, and a second preamplifier connected in sequence, and a compensation fiber of a preset length is connected in the reference optical path to make the optical path of the sensitive optical path and the reference optical path equal. The outputs of the first preamplifier and the second preamplifier are respectively connected to the input of the subtractor; The subtractor is used to subtract the signal output by the first preamplifier from the signal output by the second preamplifier to obtain a noise-removed photoelectric signal. The length of the compensation fiber is determined as follows: Construct an initial gyroscope test system that does not include compensation fiber; Based on the two channels of the multi-channel acquisition system, the output signals of the first photodetector and the second photodetector in the initial gyroscope test system are acquired according to the set sampling rate to obtain two time sequence signals; The correlation between two time-series signals is calculated to obtain a cross-correlation sequence. The delay between the sensitive signal and the reference signal is determined based on the cross-correlation sequence. The optical path difference between the sensitive signal and the reference signal is determined based on the delay. The length of the compensation fiber is determined based on the optical path difference. The determination of the delay between the sensitive signal and the reference signal based on the cross-correlation sequence includes: Determine the sampling location of the sampling point with the highest correlation in the cross-correlation sequence; Calculate the distance difference between the sampling location and the location of the central sampling point; The delay between the sensitive signal and the reference signal is determined based on the distance difference and the sampling rate. The delay between the sensitive signal and the reference signal is calculated using the following formula: In the formula, T The delay between the sensitive signal and the reference signal; N This is the distance difference between the sampling location of the sampling point with the highest correlation and the location of the central sampling point; f The sampling rate.

2. The system according to claim 1, characterized in that, The optical path difference between the sensitive signal and the reference signal is calculated using the following formula: In the formula, S The optical path difference between the sensitive signal and the reference signal; c It is the speed of light in a vacuum.

3. The system according to claim 2, characterized in that, The length of the compensation fiber is calculated using the following formula: In the formula, L To compensate for the length of the optical fiber; r To compensate for the refractive index of the optical fiber.

4. The system according to claim 1, characterized in that, The sensitive fiber ring and the reference fiber ring are of equal length and are wrapped around the same fiber ring; The reference fiber ring functions as both a pad fiber ring and a reference optical transmission ring, and both the sensitive fiber ring and the reference fiber ring have two pigtails.

5. The system according to claim 1, characterized in that, The compensation fiber of the preset length is fused to the fiber between the reference fiber ring and the second photodetector.

6. The system according to claim 1, characterized in that, The electrode parameters of the photoelectric modulator are determined in the following manner: A finite element simulation model of an optoelectronic modulator is constructed; the simulation model includes equivalent transverse resistance and capacitance and equivalent longitudinal resistance and capacitance. Based on the simulation model, the equivalent resistance and capacitance parameters of the optoelectronic modulator under different electrode parameters are calculated to obtain multiple sets of equivalent resistance and capacitance parameters; the electrode parameters include electrode width and electrode spacing. Based on each set of equivalent resistance and capacitance parameters, a quantitative relationship is determined between the drift time and drift amount of the effective modulated electrical signal on the photoelectric modulator and the electrode parameters. Based on the quantitative relationship, the final electrode parameters of the photoelectric modulator under the set requirements are determined; the set requirements include the set drift amount and the set drift time.

7. The system according to claim 6, characterized in that, Based on the simulation model, the equivalent resistance and capacitance parameters of the photoelectric modulator under different electrode parameters are calculated respectively, resulting in multiple sets of equivalent resistance and capacitance parameters, including: Determine the lithium niobate crystal parameters of the photoelectric modulator; Set multiple different sets of electrode parameters; The electrode parameters are iterated over. For each set of electrode parameters encountered, the following steps are performed: the set of electrode parameters and the lithium niobate crystal parameters are used as input to perform electric field distribution simulation calculation on the simulation model to obtain the equivalent resistance and capacitance parameters under the set of electrode parameters; this process is repeated until all electrode parameters are traversed to obtain multiple sets of equivalent resistance and capacitance parameters.

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