谱分裂对集成光学陀螺灵敏度影响

Influence of splitting phenomenon in resonance peaks on integrated optic gyroscope’s sensitivity

为寻求谐振式集成光学陀螺可实现灵敏度的优化,基于调频光谱原理,应用双频率组合调制的闭环控制结构,在对通过陀螺核心敏感器件谐振腔的结构参数优化、调制频率选择等措施实现决定于谐振腔谐振特性一阶微分最大值的最佳灵敏度情形的理论分析基础上,研究了谐振峰分裂对陀螺灵敏度的影响。相关实验表明,对于给定结构的谐振式集成光学陀螺,理论上的最佳参数,并不能保证理论最佳灵敏度的实现。通过双频率组合调制下无源环形谐振腔谐振特性的测量,发现了谐振腔谐振峰分裂现象,分裂程度随腔长增加而趋明显;谐振峰的分裂,导致透射谱展宽;透射谱展宽后一阶微分谱最大值的下降,将使陀螺灵敏度随之劣化。为应对这种劣化,需要对系统调制频率进行相应调整,并控制腔长,以抑制峰分裂程度,进而控制对陀螺灵敏度的影响。

For the sake of performance optimization for a resonant integrated optical gyroscope（R-IOG）, some optimizing methods were theoretically analyzed based on closed-loop frequency modulation spectroscopy and verified experimentally. These methods include： Selecting suitable structure parameters for the passive ring resonator （PRR）, which works as the gyroscope core sensing ring in an R-IOG; determining the appropriate modulation frequency. Experiment results shown that even if the optimum parameters determined theoretically were satisfied for the R-IOG, its realized sensitivity was inferior to the optimum sensitivity determined theoretically. By experiment, we found the splitting phenomenon of resonance peaks in the PRR under two-frequency modulation condition, and analyzed the mechanism of this deterioration of optimum sensitivity. To solve the problem that the splitting phenomenon would be more serious with longer cavity length and degrade the sensitivity, some measures were given to restrain the deterioration, including adjusting the modulation frequency, controlling the cavity length. The test results show that the effects on sensitivity are significantly reduced by the aforementioned measures.