CAJ | 학술논문

根据考虑拉曼效应后的双折射光纤所满足的非线性相干耦合薛定谔方程,推导出了当沿两个偏振轴入射两束不同波长的激光脉冲时所产生的增益表达式.通过与入射相同频率的光脉冲所产生增益的对比,在考虑拉曼效应的情况下,讨论了入射不同频率光脉冲对增益谱的影响.结果表明,在正常色散区和反常色散区,当输入两束激光脉冲频率不同时,增益谱较输入相同频率激光脉冲时产生了明显的变化,其外侧的斯托克斯部分和反斯托克斯部分增益峰,随着群速度失配的增加强度明显加强、偏离中心频率,可以用于提取太赫兹脉冲.当两偏振模处于不同色散区时,增益谱与不考虑拉曼效应时也存在明显的不同,增益谱的对称性遭到破坏,斯托克斯部分的增益峰强度要明显高于反斯托克斯部分.
근거고필랍만효응후적쌍절사광섬소만족적비선성상간우합설정악방정,추도출료당연량개편진축입사량속불동파장적격광맥충시소산생적증익표체식.통과여입사상동빈솔적광맥충소산생증익적대비,재고필랍만효응적정황하,토론료입사불동빈솔광맥충대증익보적영향.결과표명,재정상색산구화반상색산구,당수입량속격광맥충빈솔불동시,증익보교수입상동빈솔격광맥충시산생료명현적변화,기외측적사탁극사부분화반사탁극사부분증익봉,수착군속도실배적증가강도명현가강、편리중심빈솔,가이용우제취태혁자맥충.당량편진모처우불동색산구시,증익보여불고필랍만효응시야존재명현적불동,증익보적대칭성조도파배,사탁극사부분적증익봉강도요명현고우반사탁극사부분.
The expression of gain is derived from nonlinear Schr¨odinger equation with consideration of raman effect when two laser pulses with different wavelengths are emitted into birefringence fiber along two polarization axes. The gain characteristic input laser pulses of different frequencies are revealed by comparing the laser pulses of identical frequency. The result show that the gain spectra will apparently differ when input laser pulses have different frequencies in normal dispersion regime and anomalous dispersion regime. The intensities of outboard gain peak about stokes part and anti-stokes part increase and frequency deviates from central frequency as group velocity mismatch increases. Therefore, the THz pulse can be extracted. The gain spectrum will be apparently different from that with no Raman effect taken into account, when the two polarization modes, are in different dispersion regimes. The symmetry of gain spectrum will be damaged. The intensity of gain peak of stokes is apparently stronger than the peak of anti-stoke.