光纤陀螺仪调制相位的畸变误差特性分析

干涉型数字闭环光纤陀螺中,多功能集成光学芯片(IOC)是非常关键的器件,其主要作用之一是相位调制,用于产生π/2相位偏置及产生补偿外部Sagnac相移的相位.由于IOC接收到的电场调制信号频率较高,存在多次谐波并且易受外部辐射干扰,从而导致调制相位畸变,对光纤陀螺的零偏和漂移有很大的影响.为了减小IOC调制相位畸变特性对光纤陀螺性能的影响,从理论上探讨引起调制相位畸变的因素,针对不同的误差因素而采取相应的措施来抑制并隔离误差;通过采取各种措施改善方波、阶梯波的信号质量,使IOC输出的相位畸变程度达到最小.测试结果表明,光纤陀螺中优化之后的相位调制系统满足高精度数字闭环光纤陀螺的指标要求.

Abstract：

Multi-function integrated optical chip (IOC) is an important component in the close-loop interference fiber optic gyroscope(IFOG)system. One of the main functions of IOC is the modulation of phase which includes the bias of phase in creating π/2 square waves and Sagnac phase biased by ladder waves in IFOG. Because the modulation signal of the electric field sent to integral optical chip has the characteristic of high frequency, there exists multiple harmonic waves and it is easily disturbed by external eradiation which induces modulation phase distortion and has great effect on drift and zero-bias. In order to reduce the effect of phase distortion of the integrated optical chip on the performance of FOG, focusing on the factors causing different phase errors in IOC, corresponding measures are taken to suppress and isolate the errors, adopting all means to improve the signal quality of square waves and ladder waves, reducing the modulation phase distortion to the lowest extent. The experimental results show that the optimized phase modulation system can meet the requirements of high precision IFOG.

Analysis on the Error Characteristic of Modulated Phase Distortion in Fiber Optic Gyroscope

Multi-function integrated optical chip (IOC) is an important component in the close-loop interference fiber optic gyroscope(IFOG)system. One of the main functions of IOC is the modulation of phase which includes the bias of phase in creating π/2 square waves and Sagnac phase biased by ladder waves in IFOG. Because the modulation signal of the electric field sent to integral optical chip has the characteristic of high frequency, there exists multiple harmonic waves and it is easily disturbed by external eradiation which induces modulation phase distortion and has great effect on drift and zero-bias. In order to reduce the effect of phase distortion of the integrated optical chip on the performance of FOG, focusing on the factors causing different phase errors in IOC, corresponding measures are taken to suppress and isolate the errors, adopting all means to improve the signal quality of square waves and ladder waves, reducing the modulation phase distortion to the lowest extent. The experimental results show that the optimized phase modulation system can meet the requirements of high precision IFOG.