设计了一种对称椭圆空气孔缺陷的光子晶体光纤,采用全矢量有限元法, 研究了该结构光纤基模的电场分布、双折射、色散、非线性及限制损耗等特性。结果表明：基模能量大部分限制 在光纤的纤芯。在λ=1550 nm, Λ=3.0 μm时,光纤基模的双折射达到了3.327×10-2, 并且色散值几乎为零,同时非线性系数值也达到 46.36 W-1·km-1,此外基模的 x 偏振和 y 偏 振的限制损耗分别达到为 4.907×10-7 dB/km和 6.819×10-7 dB/km。 在入射波范围为 0.60 ～1.80μm时, 该光纤在可见波段和近红外波段存在两个零点色散波长,且零点色散波长的位置随 Λ 的增大而向长波方向移动。 基于这种高双折射、高非线性系数、双零色散、低损耗的光子晶体光纤,在光纤传感、光纤通信、色散控制及非线性光学等领域都具有广阔的前景。

A kind of photonic crystal fiber with symmetrical elliptical air holes is proposed, the properties including electric field distribution, birefringence, dispersion, non-linearity and confinement loss of fundamental mode of this fiber are investigated using full vector finite element method. The results shows that the most of fundamental mode energy is limited to the fiber core. The birefringence can reach 3.327×10-2, and the dispersion value is almost zero, at the same time, the nonlinear coefficient is as high as 46.36W-1·km-1, as well as, the magnitude of confinement loss can be reduced to a value of 4.907×10-4 dB/km and 6.819×10-7 dB/km in x-polarization and y-polarization of fundamental mode respectively, when λ=1550 nm, Λ=3.0 μm. There are two zero-point dispersion wavelengths in the visible band and near infrared band of this fiber, and the position of zero-dispersion point wavelengths are move to the long-wave direction with the hole pitch Λ increases, in a range of wavelengths from 0.60 ～1.80μm. Based on the highly birefringence, highly nonlinear, two zero-dispersion and low confinement loss, the photonic crystal fiber could be widely used in optical fiber sensing, optical fiber communication, dispersion control and nonlinear optics.