结合多极法和耦合模理论,对一种典型的正六边形空气孔包层结构光子晶体光纤布拉格光栅的传输谱进行了研究,使用Matlab工具对这种光栅特性进行了计算和仿真。对比了常规单模光纤所成光栅与相同光栅周期光子晶体光纤布拉格光栅反射谱及时延特性之间的差异,并给出了定性解释。在此基础上,对光纤光栅的切趾特性进行了研究,选择不同的切趾函数,得出最佳切趾函数下光栅传输谱。理论计算和仿真结果表明,随波长增加,基模有效折射率下降;与相同周期常规光纤光栅相比,光子晶体光栅谐振波长出现蓝移;采用啁啾化处理后,10 cm长光子晶体光纤光栅可以提供1200 ps以上的线性时延。

Based on multipole method and coupled-mode theory,the transmission spectrum of a typical hexagonal lattice photonic crystal fiber Bragg grating is analyzed and simulated by Matlab. The differences between conventional fiber grating and photonic crystal fiber grating on their transmission spectrum and delay characteristics are compared,and derived qualitatively. The apodization characters of this fiber grating are also researched,the optimal apodization function and corresponding transimission spectrum are obtained. It is found that the effective refractive indexes of core mode decline as wavelength rising,compared with the conventional fiber grating,photonic crystal fiber grating has the shorter resonant wavelength,when it is added chirp,10 cm photonic crystal fiber grating can provide 1200 ps linear delay.