高非线性光纤正常色散区利用皮秒脉冲产生超连续谱的相干特性

使用复互相干度的定义对时域光波分裂前后以及不同输入噪声、不同初始啁啾和波形下抽运脉冲在高非线性光纤中产生的超连续谱的相干度进行了数值计算,得到了光波分裂前后和不同输入噪声下生成的超连续谱的演化和相干性变化,结果表明:皮秒脉冲在高非线性光纤正常色散区产生超连续谱的相干性主要受到系统中噪声占比的影响,其中由光波分裂生成的频谱旁瓣的相干度低于由自相位调制生成的中心频谱的相干度:抽运脉冲啁啾和波形对在高非线性光纤正常色散区产生超连续谱的相干性的影响不明显,若想获得高相干的超连续谱,需要采用低噪声的脉冲进行抽运;若获得大谱宽高相干度的超连续谱,则需要合理选择皮秒脉冲的功率。

Coherence properties of supercontinuum generated by a picosecond pulse in normal dispersion region of highly nonlinear fiber

The coherence properties of the supercontinuum generated by a picosecond pulse in normal dispersion region of highly nonlinear fiber are numerically calculated and analyzed at different input noise powers by introducing the definition of the complex degree of mutual coherence. The results show that the coherence of the generated supercontinuum is affected by the noise ratio of the picosecond pulse. The coherence of the spectrum sidelobes generated by optical wave breaking is lower than that of the center part of the spectrum. The chirp of pulse and shape of pulse do not have an obvious effect on the coherence of the broaden spectrum. Low noise power input is required to obtain high coherent supercontinuum, and the pump power and waveshape should be optimized to obtain the wide bandwidth and high coherent supercontinuum.
Keywords：supercontinuumcoherence propertyhighly nonlinear fibercomplex degree of mutual coherence