微结构硫化物光纤中中红外超连续谱的产生

MidInfrared Supercontinuum Generation from Microstructured Chalcogenide Fibers

采用微结构硫化物光纤,以非线性薛定谔方程(NLSE)为理论模型,利用分步傅里叶计算方法,研究了输入脉冲的中心频率和脉宽对中红外超连续谱(SC)的影响。采用的微结构硫化物光纤具有较高的非线性效应和两个零色散波长(ZDW),且第二个零色散波在中红外波段,有利于中红外超连续谱的产生。通过仿真发现,输入脉冲的中心频率和脉宽对连续谱的产生都有很大影响。数值仿真中,输入具有不同频率和脉宽的脉冲,输入波长接近零色散点时较远离色散点时产生的中红外超连续谱要宽。而且,在保持峰值功率不变的情况下,脉宽对频谱展宽程度没有影响,但是较短脉冲产生的中红外超连续谱更为平坦。

By using microstructured chalcogenide fibers,splitstep Fourier algorithm and nonlinear Schrdinger equation（NLSE）,effects of centre frequency and pulse width of seed pulse on midinfrared supercontinuum（SC） generation are studied.The microstructured chalcogenide fibers used here have high nonlinear effect and two zero dispersion wavelengths（ZDW）.The second ZDW is in midinfrared,which is helpful to midinfrared SC generation.There are marked effects of centre frequency and pulse width of seed pulse on SC generation.In numerical stimulation,seed pulses have different frequencies and durations.Midinfrared SC generation whose input wavelength is near ZDWs is wider than those far from ZDWs.When keeping peak power invariable,frequency spectrum broadened by pulse width is steady,but the shorter pulse can generate smoother midinfrared SC.