提出了一种新的高非线性色散平坦光子晶体光纤结构,引入了一个衡量非线性和色散平坦的品质因子δ。采用平面波展开法,研究了气孔尺寸对光子晶体光纤色散特性和非线性的影响。新结构在第一圈空气孔的中间插入六个附加小孔,使得光子晶体光纤有更小的有效模场面积,提高了光纤的非线性。通过控制第一圈和第三圈空气孔以及附加小孔的直径,使得该光子晶体光纤在大约330 nm的波长范围内,光纤的色散系数介于±0.5 ps/(km·nm)之间,在大约230nm的波长范围内,光纤的色散系数介于±0.1 ps/(km·nm)之间,在大约200 nm的波长范围内,光纤的色散系数D的值介于±0.05 ps/(km·nm)之间。光纤的有效模场面积为2.26 μm2。衡量非线性和色散平坦的品质因子δ=11.8 ps·W/μm2。

A novel photonic crystal fiber structure with high nonlinearity and flattened dispersion is proposed and analyzed. A parameter δ is introduced to measure the nonlinearity and dispersion flattening. The effect of hole size on nonlinearity and dispersion of the photonic crystal fiber (PCF) is analyzed by the plane wave expansion method. The new structure introduces six additional smaller holes between the holes of the first ring to reduce the effective area, and increase the nonlinearity of the fiber. By optimizing the diameters of the first, third, and the additional rings of holes, a PCF with high nonlinearity and flattened dispersion is achieved. The dispersion parameter is within ±0.5 ps/(km·nm) in a 330 nm wavelength range, within ±0.1 ps/(km·nm) in a 230 nm wavelength range, and within ±0.05 ps/(km·nm) in a 200 nm wavelength range. The effective area is 2.26 μm2. The nonlinearitydispersion flattening parameter δ=11.8 ps·W/μm2.