啁啾光子晶体光纤光栅反射谱和时延特性研究

用有限元法和传输矩阵法，对基于包层空气孔为柚子型结构的光子晶体光纤啁啾光栅的反射谱进行了理论分析。通过对均匀光栅仿真结果与实验结果的对比，可知此方法是可行的。研究表明光子晶体光纤的啁啾光栅有多个明显的反射峰，并且分析了啁啾系数、折变量对各谐振峰带宽和反射率等的影响。计算结果显示，随着啁啾系数和折变量的增大，光栅反射谱呈规律变化，当啁啾系数增大到一定程度时几个反射峰会连到一起，形成一个大的反射带宽。同时对光栅基模反射谱对应的时延特性进行了研究，可知其同样具有比较平滑的时延曲线，可以用于色散补偿。

Reflection Spectra and Delay Characteristics of the Photonic Crystal Fiber Chirped Grating

Based on the finite element method and transmission matrix method, the reflection spectrum of the grapefruit-type structure photonic crystal fiber chirped grating is analyzed theoretically. Compared with the results of simulation and experimental, it is seen that the method is feasible. The results show that the chirped grating has several reflection peaks. Moreover, the influences of the chirp coefficient and refractive indexes modulation on the resonant bandwidth and reflectivity are simulated. It is found that with the increase of the chirp coefficient and refractive indexes modulation, the reflection spectrum is changed regularly. When the chirp coefficient increases to a certain extent, the four reflection peaks can be connected together to form a large reflection bandwidth. At the same time, the delay characteristics of fundamental mode are studied. It can be seen that photonic crystal fiber chirped grating has a relatively smooth delay curve, so it can be used for dispersion compensation.