CN103968821A - Two-way resonant optical gyroscope - Google Patents

Abstract

The present invention relates to a high-precision resonant optical gyroscope, specifically a dual-channel resonant optical gyroscope, comprising a first circulator CIR1, a second coupler C2, a data acquisition module, a third coupler C3 and a second photodetector PD2, The third port of the first circulator CIR1 is connected to the first input end of the third coupler C3 through an optical fiber, the second output end of the second coupler C2 is connected to the second input end of the third coupler C3, and the third coupling The output end of the device C3 is connected with the input end of the second photodetector, and the output end of the second photodetector is connected with the acquisition port of the data acquisition module; The simple harmonic superposition can form the optical synthesis principle of the beating phenomenon, and a dual-channel resonant optical gyroscope is provided. The optical gyroscope is convenient to measure the frequency difference, the gyroscope contains fewer photoelectric devices, the measured frequency difference is accurate, and there is no detection lock-up threshold area.

Description

Dual-channel resonant optical gyroscope

technical field

The invention relates to a high-precision resonant optical gyroscope, in particular to a dual-channel resonant optical gyroscope.

Background technique

Resonant optical gyroscope is a new type of angular velocity sensor with small size, low power consumption, high precision and high reliability developed after MEMS gyroscope, laser gyroscope and interferometric fiber optic gyroscope. Driven by major programs and projects such as national deep space exploration, weapon precision guidance, and Beidou navigation, the characteristics of high sensitivity, miniaturization, high stability, and high overload resistance have become the development trend of resonant optical gyroscopes, and the accuracy of signals Detection is a top priority in achieving these metrics.

The resonant optical gyroscope uses the Sagnac effect principle to measure the rotational angular velocity of the measured carrier. Specifically, the frequency of the beam emitted by the tunable narrow-linewidth light source (beam frequency less than 1KHz) inside the optical gyroscope is locked by the feedback control circuit on the feedback branch. At the center frequency of the intrinsic transmission peak of the fiber ring resonator, the amplitude change of the photoelectric detection caused by the rotation of the optical gyro strapdown carrier is converted according to the amplitude change to obtain the forward and reverse beams in the fiber ring resonator. The frequency difference between them is converted by the obtained frequency difference, so as to measure the rotational angular velocity of the measured moving carrier. Since the traditional resonant optical gyro detects the angular velocity through the frequency difference generated by rotation, the frequency difference needs to be converted from the change of the photoelectric detection amplitude, and the photoelectric detection amplitude must be obtained by modulating and demodulating the beam, so the traditional resonant The modulator, demodulator and some auxiliary optoelectronic devices are needed inside the optical gyroscope. These devices themselves are affected by vibration and white noise during the rotation process, resulting in low detection accuracy of the gyroscope. At the same time, the existence of these devices leads to a lock-up in the gyroscope detection. In the threshold area, that is, the gyroscope cannot detect extremely slow or high-speed rotation signals, and its detection range is greatly limited.

Contents of the invention

In order to solve the problems of low detection accuracy and limited detection range of the existing resonant optical gyroscope, the invention provides a dual-channel resonant optical gyroscope.

The present invention is realized by adopting the following technical scheme: a dual-channel resonant optical gyroscope, including an isolation collimation chip tunable light source FL, the output end of the isolation collimation chip tunable light source FL is connected to the input end of the optical isolator ISO through an optical fiber , the output end of the optical isolator ISO is connected to the input end of the first coupler C1 through an optical fiber, the first output end of the first coupler C1 is connected to the input end of the phase modulator PM through an optical fiber, and the output end of the phase modulator PM Connect to the first port of the first circulator CIR1 through an optical fiber, and connect the second port of the first circulator CIR1 to the first port of the fourth coupler C4 through an optical fiber;

The second output end of the first coupler C1 is connected to the first port of the second circulator CIR2 through an optical fiber, and the second port of the second circulator CIR2 is connected to the second port of the fourth coupler C4 through an optical fiber, and the fourth coupling The third port and the fourth port of the device C4 are connected to the input port of the optical fiber and the optical fiber ring resonator FRR;

The third port of the second circulator CIR2 is connected to the input end of the second coupler C2 through an optical fiber, the first output end of the second coupler C2 is connected to the input end of the first photodetector PD1 through an optical fiber, and the first photodetector The output end of the PD1 is connected to the input end of the lock-in amplifier LIA through an optical fiber, and the output end of the lock-in amplifier LIA is connected to the input end of the feedback control circuit FBC through a signal line, and the output end of the feedback control circuit FBC and the isolation collimation chip can be The feedback terminal connection of the tuning light source FL;

It also includes a data acquisition and processing module, a third coupler C3 and a second photodetector PD2, the third port of the first circulator CIR1 is connected to the first input end of the third coupler C3 through an optical fiber, and the second coupler C2 The second output terminal is connected to the second input terminal of the third coupler C3, the output terminal of the third coupler C3 is connected to the input terminal of the second photodetector PD2, and the output terminal of the second photodetector is connected to the data acquisition and processing module The collection port connection.

When working, the light beam emitted by the tunable light source FL of the isolation and collimation chip passes through the optical isolator ISO and the first beam splitter C1, and is divided into two beams of light with equal power and zero frequency difference, one of which passes through After the phase modulator PM and the first circulator CIR1, the fourth coupler C4 enters the fiber ring resonator FRR, and forms a counterclockwise beam in the fiber ring resonator FRR, and another beam of light passes through the second circulator CIR2, The fourth coupler C4 enters the fiber ring resonator FRR, forms a clockwise beam in the fiber ring resonator FRR, and the counterclockwise beam goes around in the fiber ring resonator FRR, and finally passes through the fourth coupler C4, the second The circulator CIR2 and the second coupler C2 enter the first photodetector PD1, and then enter the feedback terminal of the tunable light source FL through the lock-in amplifier LIA and the feedback control circuit FBC, and perform frequency modulation on the tunable light source FL of the isolated collimation chip, so that The frequency of the beam output by the isolated collimation chip tunable light source FL is locked at the center frequency of the transmission spectrum peak of the fiber ring resonator FRR; the clockwise beam and the counterclockwise beam go around in the fiber ring resonator FRR and then couple at the third Superimposed at the coupler C3, the superimposed beam enters the second photodetector PD2 for photoelectric conversion, and the converted electrical signal is stored in the data acquisition module; after the clockwise beam and the counterclockwise beam are superimposed by the third coupler C3, a beating phenomenon occurs , forming a beat frequency signal, the beat frequency signal is stored in the data acquisition and processing module, the wavelength of the beat frequency signal is measured by the data acquisition and processing module, and the data acquisition and processing module then according to the formula , the frequency difference between the two beams can be calculated, and the rotational angular velocity of the measured object can be obtained according to the frequency difference. The optical gyroscope does not need modulators, demodulators and some auxiliary devices inside, and will not be vibrated during the rotation process. , The influence of signal white noise reduces the detection accuracy of the gyroscope, and there is no detection blocking threshold area.

The program for calculating the frequency difference in the data acquisition and processing module is well known to those skilled in the art.

The present invention provides a simple dual-channel resonant optical gyroscope based on the principle of optical synthesis that the superposition of simple harmonic waves propagating in the same direction with small frequency differences and the same speed can form a beating phenomenon. The frequency difference is convenient, the gyroscope contains fewer photoelectric devices, the measured frequency difference is accurate, and there is no detection blocking threshold area, which solves the problems of low sensitivity and limited detection range of the existing resonant optical gyroscope.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Figure 2 is a waveform diagram of the beat frequency signal detected by the oscilloscope.

Fig. 3 is a schematic diagram of the calculated frequency difference.

Detailed ways

Dual-channel resonant optical gyro, including an isolated collimation chip tunable light source FL, the output end of the isolated collimation chip tunable light source FL is connected to the input end of the optical isolator ISO through an optical fiber, and the output end of the optical isolator ISO is connected through an optical fiber and The input end of the first coupler C1 is connected, the first output end of the first coupler C1 is connected to the input end of the phase modulator PM through an optical fiber, and the output end of the phase modulator PM is connected to the first end of the first circulator CIR1 through an optical fiber. Port connection, the second port of the first circulator CIR1 is connected to the first port of the fourth coupler C4 through an optical fiber;

The second output end of the first coupler C1 is connected to the first port of the second circulator CIR2 through an optical fiber, and the second port of the second circulator CIR2 is connected to the second port of the fourth coupler C4 through an optical fiber, and the fourth coupling The third port and the fourth port of the device C4 are connected to the input port of the optical fiber and the optical fiber ring resonator FRR;

The third port of the second circulator CIR2 is connected to the input end of the second coupler C2 through an optical fiber, the first output end of the second coupler C2 is connected to the input end of the first photodetector PD1 through an optical fiber, and the first photodetector The output end of the PD1 is connected to the input end of the lock-in amplifier LIA through an optical fiber, and the output end of the lock-in amplifier LIA is connected to the input end of the feedback control circuit FBC through a signal line, and the output end of the feedback control circuit FBC and the isolation collimation chip can be The feedback terminal connection of the tuning light source FL;

It also includes a data acquisition and processing module, a third coupler C3 and a second photodetector PD2, the third port of the first circulator CIR1 is connected to the first input end of the third coupler C3 through an optical fiber, and the second coupler C2 The second output terminal is connected to the second input terminal of the third coupler C3, the output terminal of the third coupler C3 is connected to the input terminal of the second photodetector, and the output terminal of the second photodetector is connected to the data acquisition processing module. Acquisition port connection.

Claims (1)

1. two-way resonance type optical gyroscope, comprise isolation collimation chip tunable optical source FL, the output terminal of isolation collimation chip tunable optical source FL is connected with the input end of optical isolator ISO by optical fiber, the output terminal of optical isolator ISO is connected with the input end of the first coupling mechanism C1 by optical fiber, the first output terminal of the first coupling mechanism C1 is connected with the input end of phase-modulator PM by optical fiber, the output terminal of phase-modulator PM is connected with the first port of the first circulator CIR1 by optical fiber, the second port of the first circulator CIR1 is connected with the first port of the 4th coupling mechanism C4 by optical fiber,

The second output terminal of the first coupling mechanism C1 is connected with the first port of the second circulator CIR2 by optical fiber, the second port of the second circulator CIR2 is connected with the second port of the 4th coupling mechanism C4 by optical fiber, and the 3rd port of the 4th coupling mechanism C4 is all connected with the input port of fiber annular resonant cavity FRR by optical fiber with the 4th port;

The 3rd port of the second circulator CIR2 is connected with the input end of the second coupling mechanism C2 by optical fiber, the first output terminal of the second coupling mechanism C2 is connected with the input end of the first photoelectric detector PD 1 by optical fiber, the output terminal of the first photoelectric detector PD 1 is connected with the input end of lock-in amplifier LIA by optical fiber, the output terminal of lock-in amplifier LIA is connected with the input end of feedback control circuit FBC by signal wire, and the output terminal of feedback control circuit FBC is connected with the feedback end of isolation collimation chip tunable optical source FL;

Characterized by further comprising digital sampling and processing, the 3rd coupling mechanism C3 and the second photoelectric detector PD 2, the 3rd port of the first circulator CIR1 is connected with the first input end of the 3rd coupling mechanism C3 by optical fiber, the second output terminal of the second coupling mechanism C2 is connected with the second input end of the 3rd coupling mechanism C3, the output terminal of the 3rd coupling mechanism C3 is connected with the input end of the second photodetector, and the collection port of the output terminal of the second photodetector and digital sampling and processing is connected.