利用光束传播法对带隙型光子晶体光纤(photonic crystal fiber,PCF)的泄露谱进行了数值分析.结果表明:PCF泄露谱往往具有多个带隙;泄露谱对PCF结构的变化异常敏感,泄露峰值波长和带隙波长不但与空气孔周期有关,还受空气孔直径的影响;由于PCF的空气孔内可填充液晶,泄露特性对液晶折射率的变化极其敏感,当液晶折射率增大时,峰值泄露波长和带隙波长都向长波漂移. The leakage spectra of PCF were analyzed numerically by using the beam propagation method. The results show that the PCF leakage spectrum often has multiple band gaps. The leak spectrum is sensitive to the change of PCF structure, The peak wavelength and the bandgap wavelength are not only related to the cycle of the air holes but also influenced by the diameter of the air holes. Since the air holes in the PCF can be filled with liquid crystals, the leakage characteristics are extremely sensitive to the refractive index changes of the liquid crystal. Peak leakage and bandgap wavelength drift to longwave.