Parameter Optimization of the Resonator of Resonant Photonic Crystal Fiber Optic Gyroscope Under Dynamic Conditions
Zhuo Wang, Guochen Wang and Wei Gao, Harbin Institute of Technology, China
Location: Big Sur
Parameter optimization of the resonator of resonant photonic crystal fiber optic gyroscope under dynamic conditions
(Importance of optimization of parameters)
The design and production process of photonic crystal fiber (PCF) is becoming increasingly mature, and the fiber is more and more widely used. In recent years, PCF is used in fiber optic gyroscope depending on its low noise and other advantages. The resonator fiber optic gyroscope (RFOG) provide an alternative for small size and low cost inertial sensor and inertial measurement units because of short length of fiber. As the core device of resonator photonic crystal fiber optic gyroscope, the performance of PCF resonator directly determines the accuracy of gyro, so the design and optimization of parameters of resonator is a very important step before gyroscope is applied.
(Importance of dynamic test)
The process that gyroscope is applied to the actual environment is equivalent to that the resonator is in the process of dynamic scanning, so it is necessary to carry out dynamic test of the resonator in advance. Correspondingly, it is necessary to adjust the parameters of resonator according to the dynamic test results to achieve good resonant characteristics and output results
(Innovation of this article)
In previous papers, the optimization of parameters of resonator was done under static conditions, which did not take into account the process of dynamic scanning and the effect of the modulation and demodulation. From the perspective of parameter optimization, for the first time, the laser scanning process is combined with the sinusoidal modulation process to carry out dynamic test in this paper. According to the test results, the parameters of the resonator are adjusted constantly in turn to optimize test results. In previous paper, the dynamic test of the resonator is focused on the general polarization maintaining fiber resonator. From the perspective of dynamic test of resonator, for the first time, the dynamic characteristics of PCF resonator are studied.
This paper analyzes the modulation and demodulation characteristics of resonator photonic crystal fiber optic gyroscope based on dynamic test system and optimizes parameters of resonator according to above characteristics. The analysis of modulation and demodulation characteristics includes: the modulation waveform with or without overshoot, resonant depth and finesse of resonant curve, as well as the slope of the demodulation curve. Several important parameters of the resonator are analyzed based on the modeling and theoretical simulation of the resonator dynamic test system, which include the total loss of the fiber ring resonator, the coupling coefficient and insertion loss of the coupler and the length of fiber.According to the simulation results, the basic principle of the optimization of the resonator is determined. Then the experimental results of the modulation and demodulation test are validated and compared with the theoretical analysis, and the parameters of resonator are adjusted gradually to make the modulation and demodulation characteristics optimal. Finally, the resonator optimized by the theoretical analysis method in the previous articles are compared with our new method.
(Results and Conclusion)
Firstly, the modulation and demodulation characteristics of the resonator are better in this method. The resonant depth and finesse are increased, and the sensitivity of gyro is increased by about 10%, which is conducive to improve the gyro accuracy. Secondly, the influence of coupler insertion loss is low for modulation and demodulation characteristics, while the total loss of fiber ring resonator, coupling coefficient of coupler and the length of fiber will cause a greater impact on final results. According to the simulation and experimental results analysis, the coupling coefficient of coupler and the length of fiber should be chosen appropriately to improve the sensitivity of the system and the loss of resonator should be reduced as far as possible. Thirdly, under the dynamic condition, the results of parameters optimized through this method is different from the result acquired by previous theoretical analysis. The coupling parameters and the length of fiber should be increased slightly comparing with the previous method, which is helpful to improve the performance of the gyroscope.