800nm处近零色散高非线性光子晶体光纤的设计

Design of Photonic Crystal Fiber with Nearly Zero Dispersion and High Nonlinearity at 800nm

设计了一种用于产生超连续谱的新型高非线性光子晶体光纤结构,其光纤包层空气孔大小从内到外呈凹型分布,将最内层空气孔直径d_(1)和最外两层空气孔直径d_(5)和d_(6)设置为较大值以分别获得高非线性和低损耗特性;为了降低光纤制作难度,将第二至第四层空气孔直径设置为相同。基于多极法分析了光纤包层空气孔间距Λ和各层空气孔直径对色散、非线性系数和损耗的影响规律,并设计了最佳结构参数。仿真结果表明,该结构光纤双零色散点分别为798和1260nm,色散极大值为71.6ps·nm^(-1)·km^(-1),在0.72~1.3μm波长范围内,色散斜率小于0.81ps·km^(-1)·nm^(-2),780nm处的非线性系数为153.2 W^(-1)·km^(-1),800nm处损耗为3.1×10^(-3)d B/km,性能相比市场同类型光子晶体光纤更具优势。

A novel and high nonlinear photonic crystal fiber structure for supercontinuum generation was designed, and the size of the air holes in the cladding layer of the fiber is concave. The diameter of the innermost air hole d_(1) and the diameter of the outermost two air holes of d_(5) and d_(6) are set to a larger value to obtain high nonlinearity and low loss, respectively. In order to reduce the difficulty of optical fiber fabrication, the diameters of the second to the fourth air holes are set to be the same. Based on multipole method, the effects of air hole spacing Λ and air hole diameter on dispersion, nonlinear coefficient and loss of PCF are analyzed, and the optimal structure parameters are designed. The simulation results show that the double zero dispersion points of the fiber are 798 and 1260 nm, respectively, and the maximum dispersion is 71.6 ps·nm^(-1)·km^(-1). In the wavelength of 0.72~1.3μm, the dispersion slope of the PCF structure is less than 0.81 ps·km^(-1)·nm^(-1), the nonlinear coefficient is 153.2 W^(-1)·km^(-1)at 780 nm, and the loss is 3.1×10^(-3)dB/km at 800 nm.