IFOG中相位调制器的残余强度调制及其测量

利用开环正弦波调制解调方法,推导了铌酸锂相位调制器的残余强度调制(简称RIM)对干涉型光纤陀螺(简称IFOG)信号的影响,指出在调制频率漂移或光纤环渡越时间变化时RIM可导致陀螺的零偏和噪声增大.对典型条件的计算表明,0.01°/h的IFOG容许的最大RIM为13ppm,0.1°/h的中低精度IFOG则为81ppm.提出利用锁相放大器精确测量相位调制器RIM的方法,并对国产器件进行测量,结果表明,器件RIM指标可在中低精度IFOG中应用.

Residuary intensity modulation of the phase modulator in IFOG and its measurement

The effect of the Residuary Intensity Modulation (RIM) of the phase modulators on Interferometric Fiber Optic Gyroscope (IFOG) was reasoned out by the deduction of interference signal with sin wave modulation of IFOG in open loop operation. It is pointed out that the RIM can generate signal bias or increase noise in the case of the variation of either the modulation frequency or the transition time of the light in the fiber loop. For 0.01 degree per hour of the high-resolution IFOGs, the allowable max RIM value is 13ppm in a typical calculation. As for 0.1 degree per hour IFOGs, the requirement of RIM value is below 81ppm in another typical condition. The precise measurement method of the RIM value with a phase lock amplifier was proposed and applied on a homemade phase modulator. Its RIM value meets the requirements of middle-resolution IFOG.