无源环形谐振腔(Passive ring resonator,PRR)是谐振式光学陀螺(Resonator optic gyros, ROG)的核心敏感器件,其光学传递函数的半峰全宽是决定陀螺标度因子的重要因素之一。根据多光束干涉理论,耦合系数将通过对反射式无源环形谐振腔的半峰全宽的作用而影响陀螺的标度因子。根据耦合模理论和调频检测原理,以标度因子最优为判据,推导了一般情形下耦合系数对标度因子的影响,论证了最佳耦合系数的存在与确定方法,并进行了仿真验证。结果表明,光纤陀螺中5%左右的最佳耦合系数取值不具有普遍意义,为较高波导传输损耗的聚合物集成光学陀螺结构优化提供一种新的思路。

Passive ring resonator (PRR) is the critical sensing component of a resonator optic gyroscope (ROG) and the scale factor of a resonator optic gyroscope is mainly determined by the coupling coefficient through the full width at half maximum of the passive ring resonators transfer function. A method to determine the optimal value of coupling coefficient is elaborated based on the theory of coupled-mode theory and frequency-modulation (FM) spectroscopy. Finally, emulation results is given to verify the method and prove that the value of about 5% is only correct in the situation of fiber optic gyros (FOG).