宽带调谐光子晶体光纤多功能太赫兹器件

Broadband Tuning Multifunctional Photonic Crystal Fiber for Terahertz Device

基于液晶分子的指向矢随外加电场改变而变化的特点，设计了一种新型电场调制液晶太赫兹器件。利用全矢量平面波展开法和光束传播法分别研究了光子晶体光纤的带隙位置和传输光谱的电场分布。同时，利用时域有限差分法计算了液晶分子指向矢随外电场的变化关系。结果显示该器件不仅可以在0．55THz的宽带范围内实现开关功能，且具有耦合损耗低、消光比高等优点，消光比为30．78dB。当太赫兹波的入射频率满足光纤的单偏振条件时，该器件还具有偏振控制功能，能够改变传输模式的偏振状态。

A theoretical study of liquid crystal filled photonic crystal fiber is presented. The effects of electric birefringence of liquid crystal in the liquid crystal filled photonic crystal fiber and the transmitting properties of photonic crystal fiber are investigated by using the full vector plane wave expansion and beam propagation methods. At the same time, finite different time domain method is used to calculate the change of liquid crystal molecules with the external electric field. The simulation results show that the electrically controlled liquid crystal filled photonic crystal fiber can act as a terahertz switch with about 0.55 THz bandwidth. It also has low coupling loss and high extinction ratio which is more than 30.78 dB. Furthermore, when the frequency of the incident terahertz wave meets some conditions, the device can control the polarization state of the incident terahertz wave.