磁光非线性光纤中光脉冲传播与分步傅里叶计算

【作者】 周晓璟；

【导师】 武保剑；

【作者基本信息】 电子科技大学 ， 光学工程， 2011， 硕士

【摘要】 随着人们对各种高非线性光纤的相继开发,基于光纤非线性的光子信息处理器件备受关注。磁光非线性光纤是一类具有高磁光效应和光纤非线性效应的特种光纤,在磁场传感、光通信与光信息处理领域已具有广泛应用前景。本文主要研究内容包括:1.研究了磁光光纤中光脉冲的非线性传播,介绍了磁光非线性光纤的微扰理论和基本的研究方法。将磁光效应与非线性效应视为微扰,并用附加电极化强度表示,然后根据麦克斯韦方程推导出磁光光纤中光脉冲的非线性耦合模方程。2.根据磁光光纤中的椭圆双折射特性,推导了导波光脉冲演化的本征型和非本征型非线性耦合模方程,分析了各种坐标系下修正分步傅里叶算法(SSFM)的精度。研究表明,本征型非线性耦合模方程对分步傅里叶算法的适应性最好。3.分析了光脉冲的自相位调制(SPM)特性,给出了磁光光纤等效非线性系数与本征椭圆偏振光椭圆率的关系。自相位调制引起的最大非线性相移会随着外加磁场的增加而减小,从而揭示了非线性光纤器件的磁控机理。4.通过修正分步傅里叶算法(SSFM)计算了磁光光纤中光脉冲的传播特性。研究表明,脉冲频谱会随着外加磁场的增加而展宽,磁场有助于减弱光纤非线性的偏振依赖性。更多还原

【Abstract】 With development of a variety of highly nonlinear optical fiber, photonic information processing devices based on fiber nonlinear effects are concerned. Magneto-optical nonlinear fibers, as a class of special fibers, possess high magneto-optical effects and nonlinear effects with wide application prospects in magnetic field sensing, optical communication and optical information processing field. The research works are as follows:1. Nonlinear propagation of optical pulses in magneto-optical fibers is described according to the perturbation theory. The magneto-optical effect and nonlinearity are regarded as the perturbation expressed by the additional electrical polarization. And then, the magneto-optical and nonlinear coupled mode equations of optical pulses can be derived from Maxwell’s equations.2. According to the characteristics of elliptical birefringence in magneto-optical fiber, we put forward the eigen and non-eigen nonlinear coupled-mode equations for guided optical waves and analyze the accuracy of the modified split-step Fourier method (SSFM). It shows that the eigen nonlinear coupled mode equations are fit for the modified split-step Fourier method.3. For the self-phase modulation (SPM) characteristics, the relationship between the equivalent nonlinear coefficient and the ellipticity of eigen elliptical polarized light is obtained. The maximum of nonlinear phase shift induced by SPM increases with the decrease of applied magnetic field, and then the magnetic control mechanism of nonlinearity is opened out.4. The modified split-step Fourier method (SSFM) is also used to calculate the propagation characteristics of light pulses in the fibers. With the increase of magnetic field, the pulse spectrum can be broadened and the polarization dependency of nonlinearity reduces.更多还原