北京航空航天大学 仪器科学与光电工程学院, 北京 100191
激光器是谐振式光纤陀螺(RFOG)的重要组成部分, 其光学噪声严重地限制了RFOG的输出精度。通过建立激光器偏振特性的数学模型, 分析了激光器的偏振消光比、对轴误差和偏振本征态相位差对RFOG性能的影响, 并通过实验验证了模型的正确性。此外, 提出一种基于强度调制基频解调信号的方案, 以补偿RFOG中非理想偏振态的振幅波动。实验表明, 利用该方案可将非理想偏振态下振幅波动引起的陀螺输出波动减小12dB以上。
谐振式光纤陀螺 激光器偏振特性 噪声补偿 声光移频器 标度因数非线性度 resonator fiber optic gyroscope polarization characteristic of laser noise compensation acoustooptic modulator scale factor nonlinearity
Author Affiliations
Abstract
School of Instrumentation Science and Opto-electronics Engineering, Beihang University, Beijing 100191, China
Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 dB additionally by the cavity and the total intensity suppression ratio can reach 115.74 dB. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.
060.2800 Gyroscopes 010.1350 Backscattering 060.2370 Fiber optics sensors 120.4640 Optical instruments Chinese Optics Letters
2018, 16(1): 010608
