研究了具有高双折射的光子晶体光纤(HB PCF)中均匀布拉格光栅(FBG)的光谱特性。利用紧凑的超格子模型,对光子晶体光纤的传输特性进行分析,研究正向传输和反向传输的模式之间的耦合规律,从而研究写入光子晶体光纤中的均匀布拉格光栅的特性。首先给出具有C6v对称性的零双折射光子晶体光纤中光纤布拉格光栅的布拉格波长λB随光纤结构参量的变化规律;然后分析一种高双折射光子晶体光纤中的光纤布拉格光栅的光谱特性,高双折射使两个不同偏振态的反射峰分开较大;最后分析了一种常用的双模双折射光子晶体光纤中光纤布拉格光栅的光谱特性,LP01模和LPe11模的两个偏振态对应的反射谱都由于高双折射而分开。

The spectral property of the uniform fiber Bragg grating in the high-birefringence photonic crystal fiber are studied. By using the compact supercell method, the transmission property of photonic crystal fiber is analyzed, the coupling rule of forward and backward transmission modes is studied, and properties of uniform fiber Bragg grating written in photonic crystal fiber are concluded. The dependence of Bragg wavelength λB, defined as the resonant wavelength of the fiber Bragg grating in photonic crystal fiber with C6v symmetry, on the fiber structural parameters is expressed. The spectrum of the fiber Bragg grating inscribed in a high-birefringent photonic crystal fiber is analyzed and the peaks of reflectivity with different polarization states are much separated for the high birefringent index. Finally, the spectrum of a common fiber Bragg grating in a birefringent twomode photonic crystal fiber are obtained, in which peaks of reflectivity corresponding to two polarization states of modes LP01 and LPe11 are separated due to high birefringence of the photonic crystal fiber.