高双折射光子晶体光纤中的超宽超连续谱

Ultrabroadband Supercontinuum in a High Birefringence Photonic Crystal Fiber

采用分步傅里叶算法模拟分析了飞秒脉冲在所提出的一种新型高双折射光子晶体光纤中的非线性传输及超连续谱产生,讨论了入射脉冲中心波长、峰值功率、脉冲半宽度及偏振方向对超连续谱产生的影响。结果表明:在这种高双折射光子晶体光纤中,可以实现超短脉冲在550～2 200 nm的超宽波长范围的光谱展宽;入射脉冲中心波长选择在色散曲线拐点的附近时,产生的超连续谱最宽;入射脉冲峰值功率越大,脉冲半宽度越小,其超连续谱越宽;入射偏振方向偏离某一主轴越远,光脉冲沿该主轴方向所产生的超连续谱越窄。

Nonlinear transmission and supercontinuum generation with femtosecond pulse in a new designed high birefringence photonic crystal fiber are numerically simulated and analyzed by using split-step Fourier algorithm. The influences of the center wavelength, the peak power, the half-width and the polarization direction of the input pulse on supercontinuum are discussed in detail. It is shown that the supercontinuum could be broadened to an ultra-wide wavelength range of 550-2200nm. If the center wavelength of the input femtosecond pulse is close to that of the inflexion of the dispersion curves, the spectrum will be up to the widest range. The generated supercontinuum becomes wider with increasing the peak power and the pulse half-width of the input pulse. The width of the supercontinuum will become narrower if the input polarization direction gets away from both principal axis directions. Accordingly the new designed high birefringence photonic crystal fiber could be effectively applied to the generation of ultrabroadband supercontinuum.