设计了一种低损耗、宽频段、高双折射太赫兹光子带隙光纤,呈三角晶格排列的亚波长空气孔包层实现了带隙的局域作用.利用全矢量有限元法对光纤的双折射及损耗特性进行了理论分析.结果表明,在大约0.3THz的宽频范围内,类矩形纤芯太赫兹光子带隙光纤的损耗小于0.009cm-1,相双折射在10-3数量级,群双折射可达10-2数量级. A low loss, wideband and high birefringence terahertz photonic bandgap fiber was designed to realize the bandgap localized effect by the subwavelength air-hole cladding with triangular lattice arrangement. The full-vector finite element method Birefringence and loss characteristics are analyzed theoretically.The results show that the loss of the rectangular rectangular terahertz photonic band gap fiber is less than 0.009cm-1 and the phase birefringence is on the order of 10-3 in the wide frequency range of about 0.3THz, Birefringence up to 10-2 orders of magnitude.