太赫兹双芯光子带隙光纤定向耦合器

Terahertz dual-core photonic band-gap fiber directional coupler

提出了一种低损耗、宽频段太赫兹双芯光子带隙光纤定向耦合器,光纤的包层由亚波长尺度呈三角晶格排列的空气孔组成,两个纤芯分别由去掉7个空气孔构成.利用全矢量有限元法对光纤的色散、耦合特性以及损耗特性进行了理论分析.研究表明,这种耦合器的损耗系数小于0.021 cm^(-1),更重要的是可以实现0.14 THz范围内的宽频定向耦合.这种定向耦合器在太赫兹通信系统中滤波、波分复用、偏振分离和开关等技术中有潜在的应用价值.

A low-loss and broadband terahertz twin-core photonic band-gap fiber directional coupler is proposed, which consists of a cladding with a triangular lattice array of sub-wavelength air rods and two cores formed respectively by omitting seven nearby air rods. The group veIocity dispersion, the coupling and the loss of the fibers are investigated by using a full-vector finite element method. The numerical simulations show that the loss coefficient of the coupler is less than 0.021 cm^-1, and the coupling broadband of 0.14 THz can be realized. The directional coupler has potential applications in terahertz communication systems, such as filtering, wavelength-division multiplexing, polarization isolation, switching and so on.