重构多信道光纤光栅的改进离散层析算法

Improved Discrete Layer-peeling Method for the Reconfiguration of Multi-channel Fiber Bragg Grating

对重构多信道光纤光栅的离散层析算法进行了优化.在各信道加入相移的基础上,运用非线性最小二乘法对耦合系数进行高斯曲线拟合,降低了折射率调制深度的最大值且可以将剧烈变化的折射率调制深度平滑化.仿真表明,较之改进前的折射率调制最大值(0.001 3),利用新算法在折射率调制最大值为0.000 5时成功设计了一个8信道光纤光栅,极大地降低了对光纤光敏性的要求.同时,折射率调制曲线的平滑化降低了光栅的实际刻写难度.

The discrete layer-peeling method for designing multi-channel fiber Bragg grating was optimized.Through the new method,after inserting different phase changes at different channels,the coupling coefficients was then fitted by Gaussian function to get a lower and more smooth refractive index modulation.The simulation results show that a 8-channel fiber Bragg grating is successfully designed using the proposed method with the maximum refractive index modulation of 0.000 5,much lower than that of traditional DLP method（0.001 3）,which decreases the requirement of fiber′s optical sensitivity.And,the difficulty of inscribing a fiber grating was reduced by smoothing the refractive index modulation.