光纤陀螺(IFOG)用相位调制器的残余强度调制(RIM)直接影响标度因子稳定性。对Y波导调制器残余强度调制特性进行了实验测试,根据测试结果给出了残余强度调制特性的近似公式。对开环光纤陀螺,在调制器存在内静电压时,残余强度调制对标度因子稳定性影响的大小与调制器两分支残余强度调制系数的差和内静电压成正比; 对数字闭环方式,残余强度调制不仅直接影响标度因子稳定性,也影响由2π复位环路确定的调制信号最高电压而间接影响标度因子稳定性,影响的大小与调制器两分支残余强度调制系数的差成正比,但与电光系数成反比。提出的三时隙解调方法不仅能消除残余强度调制的直接影响,也能消除通过2π复位环路的间接影响。

The residual intensity modulation (RIM) of a Y-waveguide modulator used in an interferometric fiber optic gyroscope (IFOG) directly impacts the stability of IFOG’s scale factor, RIM is tested, and based on above results, RIM’s characteristic formula is given. RIM deteriorates the scale factor stability of an open-loop IFOG when there is inner static voltage in the modulator. The deterioration is proportional to the inner static voltage and α2－α1, the difference of RIM’s coefficient between the two branches of the modulator. For a close-loop IFOG, RIM deteriorates its scale factor stability not only directly but also indirectly through 2π-replacement loop that determines the peak voltage of modulation signals. The deterioration is proportional to α2－α1, but inversely proportional to the modulator’s electro-optic coefficient. A demodulation method employing three time slots is suggested that can completely remove the direct and indirect deterioration.