【摘要】 利用激光脉冲在光纤中传播时所遵守的相干非线性薛定谔耦合方程,研究了非线性双折射色散阶跃光纤(SWDF)中两相近频率的激光脉冲,其偏振方向相互正交且平行于光纤的双折射轴,且偏振方向沿2个双折射轴的分量强度相等时,在同为反常色散区和正常色散区所产生的调制不稳定性。结果表明,在反常非线性区和正常色散区都能产生调制不稳定性;在正常色散区存在不同的调制不稳定性功率区域,对应不同的功率区域导致增益谱表现出明显的不同,并且,当输入功率和波长差(或频率差)一定时,增益谱随传输距离变化保持形态不变。更多还原

【Abstract】 The coherently coupled nonlinear Schrdinger(NLS)equation of the propagation of a light pulse in a fiber has been utilized.We have studied modulation instability of light pulse with near frequency not only in anomalous dispersion regime but also in normal dispersion regime in a nonlinear birefringent step-wise decreasing fibers(SWDF),moreover,the polarized direction along the two birefringence axes are orthogonally and the intensities along the two birefringence axes are equal.The results show that modulation instability can be produced both in anomalous dispersion regime and in normal dispersion regime.The input pulses have different gain spectra obviousiy when input power regime is different in normal dispersion regime.Furthmore,the shape of gain spectra is invariable as function of propagation distance when power of input pulse and wave length difference is const.更多还原