集成光学相位调制器相位漂移补偿方法研究

铌酸锂集成光学相位调制器是数字闭环光纤陀螺的核心器件.其半波电压随温度的变化和调制解调电路反馈通道增益的变化直接影响相位调制器调制特性,产生相位漂移,从而影响了标度因数的稳定性.为了补偿相位调制器的相位漂移,提高标度因数的稳定性,提出引入了第2反馈回路的四状态偏置调制方法,给出了偏置调制方程,并分析了偏置相位的选择对系统信噪比的影响.对采用四状态调制的光纤陀螺进行测试,所得标度因数稳定性比单闭环方波调制方案提高了近一倍.结果证明,该方法对光纤陀螺标度因数稳定性的提高是有效的,具有重要意义.

Compensation for phase drift in an integrated optical phase modulator

A lithium niobate integrated optical phase modulator is the key device in a digital closed-loop fiber optic gyroscope.However,changes to its halfwave voltage with changes in temperature cause subsequent variations of gain in the feedback loop of the modulation/demodulation circuit,directly affecting the modulation performance of the phase modulator and generating phase drift,thus reducing scale factor stability.In order to compensate for phase drift and improve scale factor stability,a four-state bias modulation method with a second feedback loop was developed.Bias modulation equations are presented in this paper.The effects of bias-phase selection on the SNR are then analyzed.A test for FOG(fibre optic gyroscope) was conducted using the proposed four-state bias modulation method.It indicated that the stability of the scale factor with the proposed method is approximately double that of the single closed-loop method.These results show that this method is significant and effective for improving scale factor stability.