Method for stable control of silicon photon-ic gyro under fast temperature variation and silicon photon-ic gyro

Abstract

The application provides a silicon photon gyroscope stable control method and silicon photon gyroscope under a rapid temperature changing condition, and the stable control method comprises the following steps: setting a light source frequency control digital interval; controlling the light source temperature to make the light source center frequency enter a resonance valley, and recording the valley entering temperature; collecting the CW and CCW resonance signals output after the light source enters the resonance cavity, and calculating the sum of the clockwise and counterclockwise resonance frequency and the light source center frequency deviation; and calculating the feedback control light source current and temperature according to the light source frequency control digital interval where the sum of the frequency deviation is located. Through the adaptive control of the light source current and temperature, the light source center frequency can quickly track the resonance frequency of the resonance cavity under the rapid temperature changing condition, the stable control of the gyroscope is realized, and the gyroscope output accuracy is improved.

Description

Technical Field

[0001] This invention belongs to the field of optical sensing technology, specifically relating to a method for stabilizing and controlling a silicon photonic gyroscope under rapid temperature change conditions, and a silicon photonic gyroscope. Background Technology

[0002] With technological advancements and expanding applications, optical gyroscopes are gradually moving towards miniaturization and lower cost, posing significant challenges to the miniaturization and cost reduction of traditional fiber optic gyroscopes. In recent years, breakthroughs in silicon-based integrated optical chips have led to their widespread application in the communications field, providing a new approach to the integration and miniaturization of optical gyroscopes – the silicon photonic gyroscope. This replaces the discrete optical components of traditional fiber optic gyroscopes with silicon-based integrated transceiver modulation chips, and replaces traditional fiber optic loops with on-chip silicon-based resonant cavity chips. This significantly reduces size, weight, cost, and power consumption, making silicon photonic gyroscopes an important development direction for inertial devices.

[0003] Silicon photonic gyroscopes typically operate in harsh environments, with typical operating temperatures ranging from -45°C to 65°C and a temperature rate of 1°C / min. Some extreme applications even reach -55°C to 85°C, with a temperature rate as high as 5°C / min. Under these conditions, stable operation of silicon photonic gyroscopes is extremely difficult. The specific analysis is as follows: The operation of silicon photonic gyroscopes is based on the rapid and stable tracking of the resonant frequency of the resonant cavity chip by the laser frequency. However, traditional light sources generally have a large temperature-center frequency drift, typically as high as GHz / °C. The temperature-resonant frequency of the resonant cavity chip is also usually as high as GHz / °C. The asymmetry between the center frequency of the light source and the resonant frequency drift means that the center frequency of the light source cannot track the resonant frequency of the silicon-based resonant cavity quickly, stably, and in real time. Once stable tracking is not possible, it often causes gyroscope output errors. Therefore, traditional silicon photonic gyroscopes are difficult to adapt to engineering applications under conditions of large temperature variations in resonant frequency. There is an urgent need for a method and device that can achieve stable control under rapid temperature changes and ensure that the gyroscope accurately outputs the carrier rotation speed signal. Summary of the Invention

[0004] To address the technical problem that gyroscopes in the prior art are prone to output errors under rapid temperature changes, this invention provides a method for stabilizing and controlling a silicon photonic gyroscope under rapid temperature changes, as well as a silicon photonic gyroscope. This method adaptively controls the light source current and temperature, enabling the center frequency of the light source to quickly track the resonant frequency of the resonant cavity under rapid temperature changes, thereby achieving stable gyroscope control and improving the gyroscope output accuracy.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] This invention provides a method for stabilizing and controlling a silicon photonic gyroscope under rapid temperature changes, comprising the following steps:

[0007] S1. Set the digital range for light source frequency control. The digital range for light source frequency control includes, in order of frequency from low to high, a closed-loop range under temperature, a linear closed-loop range for drive current, and a closed-loop range under temperature.

[0008] S2. Determine whether the center frequency of the light source has entered the resonance valley. If it has, record the temperature at this time as the initial temperature of the light source. Otherwise, control the temperature of the light source to be linearly accumulated based on the upper working extreme point of the closed loop interval at the temperature, until the center frequency of the light source enters the resonance valley. Record the temperature at this time as the initial temperature of the light source.

[0009] S3. Collect the CW resonant signal and CCW resonant signal output after the light source enters the resonant cavity, and calculate the sum of the deviations D of the clockwise and counterclockwise resonant frequencies from the center frequency of the light source. 和 ;

[0010] S4. If D 和 If it is located in the linear closed-loop region of the drive current, then according to D 和 Feedback control of the light source current; if D 和 If it lies within the closed-loop temperature range, then according to D... 和 Adjust the temperature of the light source so that D 和 Located within the linear closed-loop region of the drive current; if D 和 If it is located in the closed-loop region at temperature, then according to D 和 Adjust the temperature of the light source so that D 和 It is located in the linear closed-loop region of the drive current.

[0011] Furthermore, in step S1, the method for setting the linear closed-loop interval of the driving current is as follows:

[0012] The frequency tuning range corresponding to the linear closed-loop interval of the drive current is calculated as follows:

[0013]

[0014] Among them, V DAC1 K is the full-scale control voltage of the current-controlled DAC. 压控电流源 K is the transfer coefficient of the voltage-controlled current source. 电流-频率 D is the current-frequency tuning coefficient of the light source. i_max D i_min These are the upper and lower operating extreme points of the current linear closed-loop interval, respectively, and a is the number of bits of the current-controlled DAC;

[0015] According to F 电流 To determine D, at least one complete resonance valley of the resonant cavity must be covered. i_max D i_min Values;

[0016] The methods for setting the closed-loop interval at the specified temperature and the closed-loop interval above the specified temperature are as follows:

[0017] Based on the fact that the lower operating extreme point of the upper closed-loop interval at temperature has the same frequency as the upper operating extreme point of the linear closed-loop interval of the driving current, and the upper operating extreme point of the closed-loop interval at temperature has the same frequency as the lower operating extreme point of the linear closed-loop interval of the driving current, calculate the upper and lower operating extreme points of the closed-loop interval at temperature and the upper closed-loop interval at temperature:

[0018]

[0019]

[0020] Among them, D T_max D T_min These represent the lower and upper operating extreme points of the closed-loop interval at temperature and the closed-loop interval above temperature, respectively. DAC2 K is the full-scale control voltage of the temperature control DAC. 温度-频率 is the light source temperature-frequency tuning coefficient, and b is the number of bits in the temperature-controlled DAC.

[0021] Furthermore, the D i_max D i_min The selected values ​​ensure that the closed-loop intervals at different temperatures and the closed-loop intervals above and below the temperature limit are symmetrical about the linear closed-loop interval of the drive current. This configuration allows for rapid setting of the digital range for light source frequency control, optimizing the control rate of light source temperature and current.

[0022] Furthermore, step S4 specifically includes the following steps:

[0023] If D i_min <D 和 <D i_max Then the light source current is:

[0024]

[0025] Where i0 is the initial current setting of the light source, V DAC1 K is the full-scale control voltage of the current-controlled DAC. 压控电流源 K is the transfer coefficient of the voltage-controlled current source. 电流-频率 D is the current-frequency tuning coefficient of the light source. i_max D i_min These are the upper and lower operating extreme points of the current linear closed-loop interval, respectively, and a is the number of bits of the current-controlled DAC;

[0026] If D 和 ≥D i_max Then the temperature of the light source is:

[0027]

[0028] If D 和 ≤D i_min Then the temperature of the light source is:

[0029]

[0030] Where T0 is the initial temperature of the light source when entering the resonance valley, and V DAC2 K is the full-scale control voltage of the temperature control DAC. 温度-频率 is the light source temperature-frequency tuning coefficient, and b is the number of bits in the temperature-controlled DAC;

[0031] By adjusting the temperature of the light source, D 和 It is located in the linear closed-loop region of the drive current and performs current closed-loop control.

[0032] Furthermore, before step S2, there are also steps of powering on the gyroscope and judging the reset signal. If the reset signal is set high, the CW resonant signal and CCW resonant signal in the gyroscope register are cleared.

[0033] The initial current setting of the light source is the midpoint of the linear closed-loop range of the drive current.

[0034] Furthermore, the silicon photonic gyroscope stabilization control method further includes frequency compensation and intensity compensation steps:

[0035] S5. Apply a modulated square wave signal to the modulator, demodulate the interference signal of the light source through the resonant cavity, and output the gyroscope speed before compensation.

[0036] S6. Calculate frequency compensation parameters, including

[0037] Current-frequency compensation coefficient C i-f :

[0038]

[0039] Temperature-frequency compensation coefficient C T-f :

[0040]

[0041] Where A is the area of ​​the resonant cavity, K 电流_频率 Let λ be the current-frequency tuning coefficient of the light source, n be the refractive index of the resonant cavity, λ be the wavelength of the light in the resonant cavity, L be the cavity length, and K be the current-frequency tuning coefficient of the light source. 温度_频率 The temperature-frequency tuning factor of the light source;

[0042] S7. The gyroscope rotation speed after frequency compensation is:

[0043] D 转速_f补偿 =D 转速_补偿前 +iCi_f +TC T_f

[0044] Among them, D 转速_补偿前 The gyroscope rotation speed before frequency compensation is given, i is the current, and T is the current temperature.

[0045] S8. Calculate strength compensation parameters, including

[0046] Current-intensity compensation coefficient C i-I :

[0047]

[0048] Temperature-strength compensation coefficient C T-I :

[0049]

[0050] Among them, K 电流_强度 α is the current-intensity tuning coefficient of the light source. C For the coupler loss connecting the resonant cavity, α L ε is the resonant cavity loss, ε is the splitting ratio of the two couplers connecting the resonant cavity, FSR is the free spectral linewidth of the resonant cavity, f is the center frequency of the light source, j is the imaginary unit, and K is the resonant cavity loss. 温度_强度 This refers to the temperature-intensity tuning factor of the light source.

[0051] S9. The gyroscope rotation speed after intensity compensation is:

[0052] D 转速_I补偿 =D 转速_f补偿 +iC i_I +TC T_I

[0053] Among them, D 转速_I补偿 This represents the gyroscope rotation speed after frequency compensation.

[0054] The present invention also provides a silicon photonic gyroscope for rapid temperature changes, comprising:

[0055] An optical path module includes a light source, detectors PD1, PD2, and PD3, couplers C1, C2, and C3, a modulator, and a resonant cavity. The light source outputs light to port a of coupler C1. Ports b and c of coupler C1 are connected to the input ports of detector PD1 and modulator, respectively. The two output ports of the modulator are connected to ports a of couplers C2 and C3, respectively. Ports b of couplers C2 and C3 are connected to detectors PD2 and PD3, respectively. Ports c and d of couplers C2 and C3 are connected to the upper and lower sets of input and output ports of the resonant cavity, respectively. Detector PD1 detects the dual-beam interference signal filtered by the resonant cavity, and detectors PD2 and PD3 detect the transmitted CW and CCW resonant signals of the resonant cavity.

[0056] The circuit is used for signal processing and control of the silicon photonic gyroscope, including a modulation signal generation and compensation output module, a speed demodulation module, and a light source control module.

[0057] The modulation signal generation and compensation output module is used to generate a modulation signal, demodulate the CW and CCW resonant signals, calculate the sum of the frequency difference between the center frequency of the light source and the frequency difference between the two resonant signals, and calculate the current and temperature of the light source feedback control.

[0058] The light source control module adjusts the light source current and temperature based on the current and temperature information fed back from the light source.

[0059] The speed demodulation module is used to receive dual-beam interference signals and demodulate them to generate gyroscope speed.

[0060] Furthermore, the modulation signal generation and compensation output module is also used to perform frequency compensation and intensity compensation calculations on the calculated gyroscope rotation speed.

[0061] Furthermore, the light source is a broadband light source.

[0062] The beneficial effects of this invention compared to the prior art are as follows:

[0063] This invention proposes a silicon photonic gyroscope stabilization control method based on adaptive control of light source current / temperature. It utilizes dual detectors integrated on a silicon photonic chip to detect CW and CCW resonant signals, achieving frequency and intensity detection. Using these as inputs, a control boundary detection algorithm is introduced into the closed-loop control of the silicon photonic gyroscope, enabling stable control under rapid temperature variations. This method combines the high precision of current control with the wide range of temperature control, providing precise and stable frequency control under rapid temperature changes and suppressing gyroscope output errors introduced by temperature variations.

[0064] This invention effectively tracks the sum of the difference between the center frequency of the light source and the resonant frequency of the CW resonant cavity and the resonant frequency of the CCW resonant cavity by controlling the dual parameters of temperature and current, thus avoiding the error introduced by locking the resonant frequency of a single-channel resonant cavity.

[0065] This invention achieves effective suppression of coherent noise in traditional resonant gyroscopes by introducing a dual-coupled transmission resonant cavity into the optical path structure and based on a broadband resonance scheme.

[0066] The compensation algorithm of this invention integrates frequency compensation and intensity compensation methods. It takes the CW resonant signal and CCW resonant signal as inputs to obtain frequency compensation parameters and intensity compensation parameters, respectively. By combining the two compensation methods, it effectively suppresses intensity and frequency errors introduced during broadband light source tuning.

[0067] The frequency compensation and intensity compensation of this invention adopt a compensation formula based on the characteristic parameters of the resonant cavity. Compared with the traditional modeling compensation scheme, it has the technical characteristics of simple algorithm and accurate model, which is conducive to improving the compensation accuracy, response speed, and accuracy of silicon photonic gyroscope while ensuring its bandwidth. Attached Figure Description

[0068] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0069] Figure 1 A schematic diagram of a silicon photonic gyroscope suitable for rapid temperature changes is provided for a specific embodiment of the present invention;

[0070] Figure 2 A schematic diagram of the silicon photonic gyroscope circuit module provided in a specific embodiment of the present invention;

[0071] Figure 3 A schematic diagram of the digital range for controlling the light source frequency provided in a specific embodiment of the present invention;

[0072] Figure 4 This is a schematic diagram illustrating the resonant valley and valley entry determination of a resonant cavity, provided for a specific embodiment of the present invention. Detailed Implementation

[0073] Specific embodiments of the present invention will now be described in detail. In the following description, specific details are set forth for purposes of explanation and not limitation, in order to aid in a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments departing from these specific details.

[0074] It should be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution of the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0075] As one aspect of the present invention, a silicon photonic gyroscope suitable for rapidly changing temperature conditions is provided, the silicon photonic gyroscope structure being as follows: Figure 1 As shown, it mainly includes an optical path module and a circuit module. The optical path module consists of a light source, detectors PD1-PD3, couplers C1-C3, a modulator, and a waveguide resonant cavity. The main function of the light source is to emit light. Detector PD1 detects the rotational speed signal before gyroscope compensation by detecting the intensity of the dual-beam interference signal. The modulator modulates the signal to enhance the sensitivity of the silicon photonic gyroscope. Couplers C2-C3 and the waveguide resonant cavity together constitute the silicon photonic resonant cavity structure. Detectors PD2 and PD3 are the transmission outputs of the waveguide resonant cavity, reflecting the difference between the center frequency of the light source and the center frequency of the waveguide resonant cavity, thereby indirectly obtaining the temperature change of the silicon photonic gyroscope.

[0076] The circuit module mainly implements signal processing and control of the silicon photonic gyroscope, including a modulation signal generation and compensation output module, a light source control module, and a speed demodulation module, such as... Figure 2 As shown.

[0077] 1. The modulation signal generation and compensation output module includes:

[0078] (1) Modulation signal control unit, used to control the generation of modulation square wave signal and closed-loop sawtooth wave signal. The modulation square wave signal is applied to the modulator as a modulation signal, and the closed-loop sawtooth wave signal is applied to the modulator according to the gyroscope speed compensation information for closed-loop control.

[0079] (2) Modulation square wave and closed-loop sawtooth wave generation unit, mainly composed of waveform hardware circuits, such as DA converter, operational amplifier and matching resistors and capacitors.

[0080] (3) The demodulation unit for CW and CCW resonant signals mainly realizes the demodulation of the frequency deviation between the center frequency of the light source and the CW resonant signal and the CCW resonant signal. By calculating the sum of the two frequency differences, the magnitude of the frequency drift caused by temperature change can be obtained.

[0081] (4) Interval determination unit, used to make digital interval determination on the sum of frequency differences. Based on the determination result, calculate the feedback control drive current i and the die temperature T. By making comprehensive use of the wide range tuning advantage of die temperature and the high precision tuning advantage of drive current, the center frequency can achieve closed-loop tracking of the sum of frequency deviations of CW and CCW resonant signals.

[0082] (5) Frequency compensation unit, used to calculate frequency compensation parameters and perform frequency compensation on the gyroscope speed.

[0083] (6) Strength compensation unit, used to calculate strength compensation parameters and perform strength compensation on the gyroscope speed.

[0084] 2. Speed ​​demodulation module, used to receive the PD1 signal from the detector and demodulate it to generate the gyroscope speed before compensation.

[0085] 3. Light source control module, used to apply the calculated feedback control current and temperature to the light source, including:

[0086] (1) Current control unit, including DAC1 and voltage-controlled current source. The current control unit is a hardware circuit that realizes voltage to current.

[0087] (2) Temperature control unit, including DAC2, realizes the conversion of digital signal of light source temperature into analog signal.

[0088] In this invention, the CW and CCW resonant signals are the resonant signals transmitted clockwise and counterclockwise through the resonant cavity, respectively.

[0089] The present invention provides a silicon photonic gyroscope suitable for rapidly changing temperature conditions, which has the following characteristics:

[0090] 1) The resonant optical path structure of "wide spectrum light source + dual coupler" is adopted, which is beneficial to improving the accuracy of the gyroscope.

[0091] Couplers C2 and C3 in the figure, together with the silicon-based waveguide resonant cavity, constitute a transmission resonant structure. Clockwise and counterclockwise light are frequency-selectively filtered, and the filtered light undergoes dual-beam interference on the two interference arms of the modulator. After passing through coupler C1, the light reaches detector PD1. The intensity of the interference light on detector PD1 is proportional to the rotational speed. By demodulating the rotational speed using the interference light intensity, the magnitude of the rotation is obtained. This rotational information is then applied to the modulation signal generation and compensation module to achieve closed-loop rotational speed control for the gyroscope. In this invention, a broadband light source scheme is used to effectively suppress various coherent noises introduced by narrow-linewidth lasers in traditional silicon photonic gyroscopes, thereby improving the gyroscope's accuracy.

[0092] 2) The silicon photonic chip integrates dual detectors, which enables the center frequency of the light source to always track changes in the external temperature.

[0093] Detectors PD2 and PD3 are also integrated on the silicon photonic chip. By real-time detection of the sum of the CW resonant signals and CCW resonant signals on detectors PD2 and PD3, the magnitude of frequency drift caused by temperature changes can be obtained. Dual-parameter control of temperature and current is performed in the modulation signal generation and compensation module to effectively track the center frequency of the light source to the exact midpoint between the CW resonant cavity resonant frequency and the CCW resonant cavity resonant frequency. This ensures that the center frequency of the light source always follows the change of the resonant cavity resonant frequency with temperature, thereby suppressing the gyroscope output error introduced by large-scale, high-rate temperature changes.

[0094] 3) It integrates frequency compensation and intensity compensation units to effectively compensate for errors introduced by temperature and current tuning.

[0095] The modulation signal generation and compensation module also integrates frequency compensation and intensity compensation units. The frequency compensation unit mainly performs output frequency compensation based on the frequency compensation parameter formula, the current current i, and the current temperature T. The intensity compensation unit performs output intensity compensation based on the intensity compensation parameter formula, the current current i, and the current temperature T. Through these two compensation methods, the intensity-type and frequency-type output errors introduced by the temperature and current tuning of the light source in the silicon photonic gyroscope are effectively suppressed.

[0096] As another aspect of the present invention, a method for stabilizing and controlling a silicon photonic gyroscope under rapid temperature changes is provided, comprising the following steps:

[0097] 1. Set the digital range for light source frequency control

[0098] The digital operating range of the silicon photonic gyroscope control circuit under rapid temperature change conditions is as follows: Figure 3 As shown in the figure, the right coordinate represents the frequency tuning range of the light source, and the left coordinate corresponds to the digital value of the light source temperature / current control DAC. It should be noted that in this embodiment, to simplify calculations, the DAC bits for the light source current control unit and the temperature control unit are the same, both being 16 bits. 16 =65536.

[0099] The digital range for light source frequency control mainly includes the linear closed-loop range of the drive current and the upper / lower closed-loop range of the temperature. (Setting D...) i_max Digital quantity and D i_min The digital values ​​represent the upper and lower operating extreme points of the current linear closed-loop interval, respectively, and D is set. i_min ~D i_max The digital quantity is the linear closed-loop range of the drive current, according to the control range V of the current-controlled DAC (DAC1). DAC1 And the transfer coefficient K of the voltage-controlled current source 压控电流源 Current-frequency tuning coefficient K 电流-频率The frequency tuning range corresponding to the linear closed-loop interval of the drive current can be obtained as follows:

[0100]

[0101] Among them, V DAC1 K is the full-scale control voltage of the current-controlled DAC. 压控电流源 K is the transfer coefficient of the voltage-controlled current source. 电流-频率 D is the current-frequency tuning coefficient of the light source. i_max D i_min These are the upper and lower operating extreme points of the linear closed-loop current range, respectively.

[0102] By setting D respectively i_max and D i_min This ensures that the linear closed-loop interval of the driving current at least covers the complete resonant valley range F of the first-order resonant cavity. i_max (like Figure 4 As shown), that is, satisfying: F 电流 Can cover -F i_max ~F i_max area.

[0103] By using the above method for setting the current linear closed-loop interval, the control accuracy corresponding to the minimum position of the current linear closed-loop interval can be achieved as follows:

[0104]

[0105] According to formula (2), the control accuracy corresponding to the minimum bit of the current linear closed loop is usually in the range of several kHz to tens of kHz. In fact, it takes into account the output rate of the DAC, which is as high as tens of MHz. By averaging the output multiple times, the current control accuracy of the current linear closed loop region can be significantly improved to the level of several Hz to tens of Hz.

[0106] Set 0~D T_min The digital quantity is the closed-loop interval at temperature, D T_max The 65536 digital value represents the closed-loop temperature range, combined with the full-scale control range V of the temperature-controlled DAC (DAC2). DAC2 Temperature-frequency tuning coefficient K 温度-频率 Based on these parameters, the frequency tuning range for temperature control can be obtained as follows:

[0107]

[0108] Among them, D T_max Digital quantity and D T_minThe digital values ​​represent the lower operating extremum of the closed-loop interval above temperature and the upper operating extremum of the closed-loop interval below temperature, respectively. To achieve full coverage of the frequency tuning range and avoid uncontrollable special elements (ensuring the frequencies corresponding to the upper and lower closed-loop intervals above and below temperature are continuous with the frequency range corresponding to the linear closed-loop interval below current), D is determined... i_max and D i_min After determining the value, D is obtained according to formulas (4) and (5) respectively. T_max and D T_min value:

[0109]

[0110]

[0111] D set in the above manner T_max and D T_min This allows the upper / lower closed-loop temperature range to at least cover the frequency drift introduced by the resonant cavity under temperature changes of -55℃ to 75℃.

[0112] The temperature control range design covers most engineering applications. Through precise subdivision of the current and temperature tuning ranges, it comprehensively utilizes the high precision and fast response frequency tuning characteristics of the drive current, as well as the wide tuning range of the die temperature.

[0113] II. The procedure flow for the stabilization control method of silicon photonic gyroscope under rapid temperature change conditions is as follows:

[0114] S001: Circuit powered on.

[0115] The signal detection circuit is powered on;

[0116] S002: Reset signal determination:

[0117] If the reset signal is high, the program initializes and the register data in the CW / CCW resonant signal demodulation unit is cleared; if it is low, the program continues to wait for the reset signal.

[0118] S003: Resonance frequency valley determination:

[0119] Valley entry determination is performed based on the CW resonant signal on detector PD2 (or the CCW resonant signal on detector PD3). The determination rule is to compare the voltage of detector PD2 with the standard comparison level. If the voltage of detector PD2 is above the standard comparison level, the center frequency of the light source is considered to be outside the valley; otherwise, the center frequency of the light source is considered to be within the resonance valley range. If it is determined that the light source has not yet entered the resonance valley range, the standard comparison voltage is set low, and the temperature control DAC (DAC2) is set to D. T_min In D T_minBased on this, the temperature digital value is linearly accumulated until the center frequency of the light source enters the resonant valley range. The standard comparison voltage is set high, and at this time the temperature control DAC maintains the current temperature T0 and is controlled by the drive current.

[0120] S004: Resonant signal demodulation:

[0121] Once the standard comparison voltage is set high, it indicates that the resonance valley range has been entered. For both the CW and CCW resonant signals, frequency difference demodulation of the CW and CCW signals is directly performed to obtain the frequency difference f between the light source center frequency and the CW resonant frequency. cw The frequency difference f between the light source frequency and the CCW resonant frequency ccw Demodulation value D fcw D fccw The data is stored in the CW demodulation register and the CCW demodulation register, respectively.

[0122] S005: Closed-loop resonant frequency under rapid temperature changes:

[0123] After demodulation is complete, perform f cw f ccw Sum value solution (using the frequency difference f) cw Frequency difference f ccw All are absolute values, i.e., D 和 =D fcw +D fccw Then for D 和 Perform interval determination:

[0124] ① If we determine D 和 Located in the linear closed-loop region of the drive current, i.e., D i_min <D 和 <D i_max Then directly based on D 和 The numerical feedback control of the drive current is used to obtain the current drive current i, as shown in formula (6), where i0 is the initial set current. By continuously adjusting the drive current, the center frequency of the light source is locked to the sum of the CW resonant signal and the CCW resonant signal. Specifically, this is achieved by applying current control pins to the light source.

[0125]

[0126] Where i0 is the initial current setting of the light source, V DAC1 K is the control voltage for the current-controlled DAC. 压控电流源 K is the transfer coefficient of the voltage-controlled current source. 电流-频率 D is the current-frequency tuning coefficient of the light source. i_max D i_min These are the upper and lower operating extreme points of the linear closed-loop current range, respectively.

[0127] ② If it is determined to be within the closed-loop temperature range, i.e., D 和 ≥D i_max If the temperature is rising rapidly, it is necessary to pull it into the linear closed-loop range of the drive current through temperature control. At this time, the corresponding die temperature T is set as shown in formula (7), which is specifically achieved by applying the temperature control pin of the light source.

[0128]

[0129] Where T0 is the initial temperature of the light source when entering the resonance valley, and V DAC2 K is the full-scale control voltage of the temperature control DAC. 温度-频率 This is the temperature-frequency tuning coefficient of the light source.

[0130] When D is controlled by the die temperature 和 Once the linear closed-loop range of the driving current is reached, the driving current i is controlled according to formula (6) until the center frequency of the light source is locked to the sum of the CW resonant signal and the CCW resonant signal.

[0131] ③ If it is determined to be within the closed-loop region at temperature, i.e., D 和 ≤D i_min If the temperature is rapidly decreasing, it is necessary to pull it into the linear closed-loop range of the drive current through temperature control. The corresponding temperature T is set as shown in formula (8):

[0132]

[0133] When D is controlled by the die temperature 和 Once the linear closed-loop range of the driving current is reached, the driving current i is controlled according to formula (6) until the center frequency of the light source is locked to the sum of the CW resonant signal and the CCW resonant signal.

[0134] S006: Demodulation of interference signal before compensation:

[0135] First, the modulation signal generation unit generates a modulated square wave signal with a frequency of f1, which is then applied to the modulation electrode of the phase modulator. During this process, the interference signal demodulation module performs digital correlation detection on the output signal of detector PD1 to achieve interference signal demodulation. The demodulation frequency is f1, and the demodulated output is D. 转速_补偿前 This refers to the gyroscope speed output before compensation;

[0136] S007: Frequency compensation parameter calculation:

[0137] Based on the relationship between the current i and the frequency K given by the light source 电流_频率 Obtain the current-frequency compensation coefficient C i-f as follows:

[0138]

[0139] Where A is the area of ​​the resonant cavity, K 电流_频率 λ is the current frequency tuning coefficient of the light source, n is the refractive index of the resonant cavity, λ is the wavelength of the resonant cavity light, and L is the cavity length of the resonant cavity.

[0140] Based on the relationship between temperature T and frequency K given by the light source 温度_频率 Obtain the temperature-frequency compensation coefficient C T-f as follows:

[0141]

[0142] Among them, K 温度_频率 is the current frequency tuning coefficient of the light source.

[0143] S008: Frequency Compensation

[0144] The D signal is output by the interference signal demodulation module. 转速_补偿前 As input, along with the current drive current i and the current die temperature T, the frequency compensation unit calculates the speed output signal after frequency compensation, as shown in formula (11):

[0145] D 转速_f补偿 =D 转速_补偿前 +iC i_f +TC T_f (11)

[0146] S009: Calculation of strength compensation parameters:

[0147] Based on the relationship between the driving current i and the intensity K given by the light source 电流_强度 And the current-intensity compensation coefficient C is obtained from the resonant cavity transfer function. i-I as follows:

[0148]

[0149] Among them, K 电流_强度 α is the tuning coefficient for the light source current intensity. C For the losses of couplers C2 and C3, α L ε is the waveguide resonant cavity loss, ε is the splitting ratio of coupler C2 and coupler C3, FSR is the free spectral linewidth of the resonant cavity, f is the center frequency of the light source, and j is the imaginary unit.

[0150] Based on the relationship between the set temperature T and intensity K given by the light source 温度_强度 And the temperature-intensity compensation coefficient C is obtained from the resonant cavity transfer function. T-I as follows:

[0151]

[0152] Among them, K 温度_强度 is the temperature intensity tuning factor of the light source.

[0153] S010: Strength Compensation

[0154] Output D from the frequency compensation unit 转速_f补偿 As input, along with the current drive current i and the current die temperature T, the speed output signal after frequency compensation is calculated in the strength compensation unit. The calculation formula is shown in formula (14):

[0155] D 转速_I补偿 =D 转速_f补偿 +iC i_I +TC T_I (14)

[0156] The V involved in this embodiment DAC1 V DAC2 K is a metric parameter for DAC. 电流-频率 K 温度-频率 K 电流_强度 K 温度_强度 The specifications of the light source can all be determined from the technical manual.

[0157] The features described and / or illustrated above with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, and / or in combination with or in lieu of features in other embodiments.

[0158] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, components, or combinations thereof.

[0159] Many features and advantages of these embodiments are apparent from this detailed description, and therefore the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since many modifications and alterations will readily occur to those skilled in the art, the embodiments of the invention are not intended to be limited to the precise structures and operations illustrated and described, but rather to encompass all suitable modifications and equivalents falling within their scope.

[0160] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0161] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. A method for stabilizing and controlling a silicon photonic gyroscope under rapidly varying temperature conditions, characterized in that, Includes the following steps: S1. Set the digital range for light source frequency control. The digital range for light source frequency control includes, in order of frequency from low to high, a closed-loop range under temperature, a linear closed-loop range for drive current, and a closed-loop range under temperature. S2. Determine whether the center frequency of the light source has entered the resonance valley. If it has, record the temperature at this time as the initial temperature of the light source. Otherwise, control the temperature of the light source to be linearly accumulated based on the upper working extreme point of the closed loop interval at the temperature, until the center frequency of the light source enters the resonance valley. Record the temperature at this time as the initial temperature of the light source. S3. Collect the CW resonant signal and CCW resonant signal output after the light source enters the resonant cavity, and calculate the sum of the deviations between the clockwise and counterclockwise resonant frequencies and the center frequency of the light source. ; S4. If If it is located in the linear closed-loop region of the drive current, then according to Feedback control of the light source current; if If it is located in the closed-loop temperature range, then according to Adjust the temperature of the light source so that Located within the linear closed-loop region of the drive current; if If it is located within the closed-loop region at temperature, then according to Adjust the temperature of the light source so that It is located in the linear closed-loop region of the drive current.

2. The stability control method according to claim 1, characterized in that, In step S1, the method for setting the linear closed-loop interval of the driving current is as follows: The frequency tuning range corresponding to the linear closed-loop interval of the drive current is calculated as follows: ,in, K is the full-scale control voltage of the current-controlled DAC. 压控电流源 K is the transfer coefficient of the voltage-controlled current source. 电流-频率 This is the light source current-frequency tuning coefficient. , These are the upper and lower operating extreme points of the linear closed-loop current range, respectively. The number of bits for the current-controlled DAC; in accordance with The design must cover at least one complete resonant valley of the resonant cavity to determine , Values; The methods for setting the closed-loop interval at the specified temperature and the closed-loop interval above the specified temperature are as follows: Based on the fact that the lower operating extreme point of the upper closed-loop interval at temperature has the same frequency as the upper operating extreme point of the linear closed-loop interval of the driving current, and the upper operating extreme point of the closed-loop interval at temperature has the same frequency as the lower operating extreme point of the linear closed-loop interval of the driving current, calculate the upper and lower operating extreme points of the closed-loop interval at temperature and the upper closed-loop interval at temperature: , ,in, , These represent the lower and upper operating extreme points of the closed-loop interval at temperature and the upper closed-loop interval at temperature, respectively. K is the full-scale control voltage of the temperature control DAC. 温度-频率 This is the temperature-frequency tuning factor of the light source. The number of bits for temperature-controlled DACs.

3. The stability control method according to claim 2, characterized in that, The , The value is chosen to make the closed-loop interval at temperature and the closed-loop interval above temperature symmetrical about the linear closed-loop interval of the driving current.

4. The stability control method according to claim 2, characterized in that, Step S4 specifically includes the following steps: like Then the light source current is: ,in, Set the initial current for the light source. K is the full-scale control voltage of the current-controlled DAC. 压控电流源 K is the transfer coefficient of the voltage-controlled current source. 电流-频率 This is the light source current-frequency tuning coefficient. , These are the upper and lower operating extreme points of the linear closed-loop current range, respectively. The number of bits for the current-controlled DAC; like Then the temperature of the light source is: , like D 和 ≤ D i_min， The temperature of the light source is: ,in, The initial temperature of the light source when entering the resonance valley. K is the full-scale control voltage of the temperature control DAC. 温度-频率 This is the temperature-frequency tuning factor of the light source. The number of bits for temperature-controlled DAC; By adjusting the temperature of the light source, It is located in the linear closed-loop region of the drive current and performs current closed-loop control.

5. The stability control method according to claim 4, characterized in that, The initial current setting of the light source is the midpoint of the linear closed-loop range of the drive current.

6. The stability control method according to claim 1, characterized in that, Before step S2, there are also steps of powering on the gyroscope and judging the reset signal. If the reset signal is set high, the CW resonant signal and CCW resonant signal in the gyroscope register are cleared.

7. The stability control method according to claim 1, characterized in that, It also includes frequency compensation and intensity compensation steps, as detailed below: S5. Apply a modulated square wave signal to the modulator, demodulate the interference signal of the light source through the resonant cavity, and output the gyroscope speed before compensation. S6. Calculate frequency compensation parameters, including Current-frequency compensation coefficient C i-f : , Temperature-frequency compensation coefficient C T-f : Where A is the resonant cavity area, K 电流_频率 Let be the current-frequency tuning coefficient of the light source, and n be the refractive index of the resonant cavity. Where is the wavelength of the resonant cavity light, L is the cavity length, and K is the resonant cavity length. 温度_频率 The temperature-frequency tuning factor of the light source; S7. The gyroscope rotation speed after frequency compensation is: Among them, D 转速_补偿前 The gyroscope rotation speed before frequency compensation is given, i is the current, and T is the current temperature. S8. Calculate the strength compensation parameters, including: Current-intensity compensation coefficient C i-I : ; Temperature-strength compensation coefficient C T-I : ,in, This is the light source current-intensity tuning factor. For the coupler loss connecting the resonant cavity, For resonant cavity loss, The splitting ratio of the two couplers connecting the resonant cavity is given by , FSR is the free spectral linewidth of the resonant cavity, f is the center frequency of the light source, and j is the imaginary unit. This refers to the temperature-intensity tuning factor of the light source. S9. The gyroscope rotation speed after intensity compensation is: ,in, This represents the gyroscope rotation speed after frequency compensation.

8. A silicon photonic gyroscope for rapidly varying temperatures, characterized in that, The silicon photonic gyroscope employs the stabilization control method according to any one of claims 1 to 7, comprising: The optical path includes a light source, detectors PD1, PD2, and PD3, couplers C1, C2, and C3, a modulator, and a resonant cavity. The light source outputs light to port a of coupler C1. Ports b and c of coupler C1 are connected to the input ports of detector PD1 and modulator, respectively. The two output ports of the modulator are connected to ports a of couplers C2 and C3, respectively. Ports b of couplers C2 and C3 are connected to detectors PD2 and PD3, respectively. Ports c and d of couplers C2 and C3 are connected to the upper and lower sets of input and output ports of the resonant cavity, respectively. Detector PD1 detects the dual-beam interference signal filtered by the resonant cavity. Detectors PD2 and PD3 detect the transmitted CW and CCW resonant signals of the resonant cavity. The circuit is used for signal processing and control of the silicon photonic gyroscope, including a modulation signal generation and compensation output module, a speed demodulation module, and a light source control module. The modulation signal generation and compensation output module is used to generate a modulation signal, demodulate the CW and CCW resonant signals, calculate the sum of the frequency difference between the center frequency of the light source and the frequency difference between the two resonant signals, and calculate the current and temperature of the light source feedback control. The light source control module adjusts the light source current and temperature based on the current and temperature information fed back from the light source. The speed demodulation module is used to receive dual-beam interference signals and demodulate them to generate gyroscope speed.

9. The silicon photonic gyroscope according to claim 8, characterized in that, The modulation signal generation and compensation output module is also used to perform frequency compensation and intensity compensation calculations on the calculated gyroscope rotation speed.

10. The silicon photonic gyroscope according to claim 8, characterized in that, The light source is a broadband light source.

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