相位掩模板接缝相差对光栅时延纹波的影响

Impact of Phase Masks′ Stitching Errors on the Time Delay Ripple of the Chirped Fiber Bragg Grating

电子束刻蚀啁啾相位掩模板采用的是分步啁啾法,而掩模板制造过程中分步之间的接缝误差是啁啾光纤光栅产生时延纹波的一个重要因素。该文以分步步长1 mm,总长度140 mm的相位掩模板为例,理论分析和比较了不同接缝误差对啁啾光纤光栅时延纹波的影响。分析表明,最大相位误差为0.05 rad和0.08 rad时,光栅时延纹波的统计平均分别为14.491 ps和22.38 ps。进行相关试验研究以上相位掩模板写入光栅的时延特性,得出结论与理论分析一致。

The chirped electron-beam written phase mask is fabricated by step-chirped method. The step-chirped phase mask is a useful and powerful device for realizing a nonlinearly or linearly stepwise chirped fiber grating with a broad bandwidth. But the stitching errors of electron-beam written phase masks always occur between neighboring sections. The stitching errors can badly impact on the time delay ripple of chirped fiber Bragg gratings （FBGs）. The 140 mm-length chirped FBGs, which are written by using 1 mm-stepwise chirped phase mask, have been studied by simulation and experiment. The simulation results agree well with those of the experiment.