一种高双折射大模场面积的光子晶体光纤

A large mode-area photonic crystal fiber with high birefringence

为了解决光纤在大的模场面积、高的双折射、低的弯曲损耗以及单模传输方面的均衡问题,设计了一种具有高双折射的大模场面积光子晶体光纤.该光纤包层由四圈三角晶格圆形空气孔组成,纤芯由矩形晶格椭圆空气孔组成,研究了结构参数对光纤的有效模面积、双折射、泄露损耗、弯曲损耗以及单模传输等特性的影响.数值分析证明,在1.55μm波长处,通过对光纤参数的调整,可实现4.47×10-4的双折射,377μm2的有效模面积,0.08dB.km-1的泄露损耗以及0.156m的可容许弯曲半径.与此同时,通过对参数的进一步设计,可得到1.3～1.68μm波长范围内的低泄露损耗单模单偏振光子晶体光纤,有效克服了光纤在偏振串扰、偏振模色散以及偏振相关损耗等方面的问题.

In order to realize the tradeoff among large mode-area, large birefringence, low bending loss, and single mode operation, a large mode-area photonic crystal fiber with high birefringence was proposed. The fiber cladding is formed by four rings of circular air holes with triangular lattice, and the fiber core is composed of elliptical holes with rectangular lattice. The influences of structural parameters on effective mode-area, birefringence, confinement loss, bending loss, as well as single mode operation of the fiber were investigated. Numerical investigation demon- strated that birefringence of 4.47X 10-4 , effective mode-area of 377 μm2 , confinement loss of 0.08 dB km 1 and allowable bending radius of 0. 156 m at the wavelength of 1.55 μm can be achieved based on the choice of parameters of the fiber. Besides, a single polarization single mode photonic crystal fiber with low confinement loss operating o- ver the wavelength ranging from 1.3 to 1.68 μm was also proposed with more detailed design. This design over- comes problems, such as polarization crosstalk, polarization mode dispersion, polarization dependent loss.