光子晶体太赫兹波导的损耗特性

Loss Characteristics of Photonic Crystal Fiber as Terahertz Waveguide

提出了一种新型光子晶体太赫兹(THz)波导,该波导包层为硅介质中含有按三角形格子周期排列的空气孔,纤芯为有机材料聚乙烯(PE).应用平面波法(PWM)分析了这种光子晶体太赫兹波导的带隙结构,研究了空气填充率变化对光子带隙(PBG)结构的影响;然后应用频域有限差分法(FDFD)对不同参数太赫兹波导的损耗进行了计算.结果表明,这是一种适合太赫兹波传输的带隙效应波导,选择较高填充率,较大孔间距,较多周期结构层数可以得到较低的泄漏损耗,选取合适的参数损耗最低值可以达到1.5 dB/km.

A new type of terahertz photonic crystal waveguide, whose clad made of silicon contains periodic circular air holes arranged as triangular lattice and core is polythene （PE）, is presented. Bandgap distribution characteristic of this photonic crystal terahertz waveguide and how air-filling factors affect the bandgap distribution characteristic are investigated by plane wave method （PWM）. Then loss characteristics of the photonic crystal terahertz waveguide with different parameters are computed by finite-difference frequency-domain method （FDFD）. Results show that this waveguide is a sort of photonic band gap guiding fiber with good capability to transmit terahertz wave. With higher air-filling factors, larger spacing between air holes and more circular structures in the cladding layer, lower leakage loss could be achieved. The lowest loss could be less than 1.5 dB/km if parameters are chosen appropriately.