紫外写入光纤光栅用亚μm相位掩模板制作误差容限分析

Analysis on Tolerance for Fabrication Error of Phase Mask for UV written Fiber Bragg Grating

本文采用电磁波标量衍射理论研究了紫外写入光纤光栅用亚μｍ相位掩模的近场衍射特性，并据此得出了零级衍射抑制的条件，采用数值模拟方法研究了相位掩模制作误差对零级衍射抑制的影响。分析表明，为使零级衍射效率小于５％，相位掩模的刻槽深度和占空比制作误差必须控制在｜Δｈ｜＜３８ｎｍ和｜Δｆ｜＜０．１１的范围内。

The near field diffraction characteristics of the phase mask for UV written fiber Bragg grating is investigated using electromagnetic wave scalar diffraction theory.The condition for zero order diffraction depression is obtained and the effects of fabrication error of phase mask on zero order diffraction depression are simulated numerically.The result shows that the groove depth and duty cycle error of phase mask must be controlled within the range of |Δh| <38nm and |Δf| <0.11 respectively in order to make the zero order diffraction efficiency less than 5%.