从实验和数值仿真两方面研究了不同宽度的脉冲抽运情况下,全正色散光子晶体光纤中超连续谱(SC)产生的物理机制,并比较超连续谱的相干性。当抽运源为高峰值功率短脉冲时,光谱展宽的主要非线性效应为自相位调制,因此,数值仿真得到的超连续谱相对于抽运波长呈对称展宽的趋势,超连续谱相干性较好。当抽运源为600ps的长脉冲时,产生超连续谱的主要非线性效应是受激拉曼散射,因此,超连续谱相对于抽运波长向长波方向展宽。
Generation and coherence of the supercontinuum (SC) in all-normal dispersion photonic crystal tiber are numerically and experimentally investigated. Different pumping pulses are used in the investigation. In the case of high power short pulse, self-phase modulation plays a crucial role in the SC generation. Spectra are symmetrically spreading at both sides of the pump wavelength, and the SC is highly coherent. When the width of the pump pulse is as large as 600 ps, stimulated Raman scattering is the main nonlinear effect, so supercontinuum is translered towards the longer wavelengths with respect to pumping wavelength.