利用复模式耦合模理论分析了基于闪耀光纤布拉格(Bragg)光栅功率检测的折射计中不同设计参数对折射计性能的影响。利用完全匹配层(PML)技术简化了辐射模分析模型。分析结果表明,随着光栅倾斜角度的增大,折射计的感应范围向折射率较小的方向移动。随着光栅长度以及折射率调制强度的增大,折射计的灵敏度增大,但折射率感应范围不变。同时这种折射计具有偏振依赖性,随着光栅倾斜角的增大偏振依赖性提高。因此在这种传感系统中需要引入精确且稳定的偏振控制。

The power-referenced refractometer based on tilted fiber Bragg grating is investigated theoretically by complex mode coupled mode theory. The use of perfectly matched layer (PML) technique simplifies the radiation mode model. The numerical results show that with the increase of tilted angle,the sensing range shifts to smaller refractive index region. With the increase of the grating length and the index modulation strength,the sensitivity of the refractometer increases,but sensing range unchanged. This refractometer is polarization dependent,and the polarization dependency raise with the increase of grating tilted angle. Therefore,precise and stable polarization control is essential for such kind of sensing system.