THz光子晶体光纤的模式及色散特性分析

利用等效折射率法得到了光子晶体光纤的特征方程,该文讨论了光子晶体光纤在THz频段的模式分布及色散特性。结果发现:光纤包层空气孔间距固定,减小空气孔半径,包层等效折射率增大,高次模截止频率增大,色散最大值减小,零色散及最大色散对应的频率增大;包层空气填充率固定,增大空气孔半径,包层折射率增大,高次模截止频率增大,色散最大值增大,零色散及最大色散对应的频率减小。通过适当调节包层空气孔间距和空气孔大小,可在很宽的频带内实现单模、零色散THz波传输。

Study of Waveguide Mode and Dispersion Property in THz Photonic Crystal Fiber

The characteristic equation of THz photonic crystal fibers is obtained with effective refractive index method. The mode distribution and dispersion are discussed. It's found that when air hole pitch is fixed, the cladding effective refractive index of photonic crystal fiber (PCFs), the cut-off frequency of higher modes, and the frequency of maximum and zero dispersion will become larger, the maximum dispersion will become smaller if the air hole radius decreases; when air-filling fraction is fixed, the cladding effective refractive index, the cut-off frequency of higher modes, and the maximum dispersion will become larger, the frequency of maximum and zero dispersion will become smaller if air hole radius increases. The transmission with single-mode zero dispersion in THz region can be realized according to the changes of air hole pitch and the air hole radius.