光子晶体光纤布拉格光栅传输谱特性的分析

研究光子晶体光纤中光纤光栅的传输谱特性对于研制基于光子晶体光纤的光纤光栅器件有着重要的意义。结合耦合模理论和光束传输相关函数方法,对一种典型光子晶体光纤中的布拉格光栅(FBG)传输谱进行了理论分析。比较了光子晶体光纤中布拉格光栅与常规布拉格光栅的传输谱。数值分析了光纤截面结构变化对于光栅传输谱的影响,并给出这种影响的定性解释。计算结果显示,与常规光纤光栅相比,包层模共振引起的损耗峰与正反向纤芯模耦合引起的损耗峰可以相比拟,而包层模共振的间隔也比常规光纤中光纤光栅的包层模共振间隔要大。同时给出了晶体光纤截面上空气孔的占空比,空气孔的排布层数对于传输谱影响的规律。

Analysis of the Transmission Spectral Characteristics of Fiber Bragg Grating in Photonic Crystal Fibers

It is essential for the development of photonic crystal fiber based fiber grating devices to study the transmission spectral characteristics of the fiber grating in photonic crystal fiber.Based on the coupled mode theory and beam propagation correlation function mode-solver,the transmission spectrum of a typical fiber Bragg grating in photonic crystal fiber is studied.The transmission spectra of fiber Bragg grating in photonic crystal fiber and conventional fiber are compared.The influence of the structure change of the fiber cross section on the transmission spectrum is simulated,and derived qualitatively.It is found that the loss peaks caused by cladding mode resonances have similar strengths with those caused by the bidirectional core mode coupling,and the spacing of cladding mode resonances is larger than that in a conventional fiber.Meanwhile,the rule of effects of duty ratio of the air holes and the layer number of the air holes on the transmission spectrum is given.