光纤孤子通信简述

光纤孤子通信是当前通信技术研究的热门课题之一。根据有关资料,本文对这一技术的发展脉络作了概述。对光纤孤子的形成,传输和系统设计方案作了重点介绍。     

聚乙炔的顺—反异构化速率

本文发展了聚乙炔中孤子、极化子的S.S.H理论;提出了各种类犁的孤子、极化子之间相互转化的模型。基于这些模型,从理论上推导出聚乙炔在不同条件下(热、光、掺杂、氧化等)异构化速率与温度、时间的依赖关系,与实验结果很好符合。预言了掺杂剂的性质对聚乙炔异构化速率的影响。     

非相对论量子流体中的孤立子运动特征

对在非相对论情况下描述量子流体运动的 GP 方程进行了全面地分析,得出了量子流体的运动是一种特殊的孤立子运动的结论.进而利用这个解及其特性解释了,在超流体中所观察到的宏观量子效应.     

Complexiton solutions for (3+1) dimensional KdV-type equation

(3$+$1) dimensional nonlinear KdV-type equation is solved  by Wazwaz and Zhaqilao’s method which is arisen by employing complex parameters instead of real parameters and considered generalization of simplified Hirota method. Complexiton solutions which include both trigonometric and exponential functions are obtained for referred equation. Also some special conditions to specify the non-singularity and type of solutions are derived.     

孤立子的弹性散射现象

采用Backlund变换法给出了KdV方程精确解,然后使用MATLAB软件画出孤立波图形,并从几何直观上解释了孤立子的弹性散射现象．     

The Jacobi elliptic function method and its application for two component BKP hierarchy equations

The periodic wave solutions for the two component BKP hierarchy are obtained by using of Jacobi elliptic function method, in the limit cases, the multiple soliton solutions are also obtained. The properties of some periodic and soliton solution for this system are shown by some figures.     

Efficient numerical algorithms for the solution of “good” Boussinesq equation in water wave propagation

This paper proposes three fast and high accuracy numerical methods for solving a nonlinear partial differential equation (PDE) describing water waves and called the Boussinesq (Bq) equation. We numerically solve the Bq equation with fourth-order time-stepping schemes in combination with discrete Fourier transform. We discretize the original PDE with discrete Fourier transform in space and obtain a system of ordinary differential equations (ODEs) which will be solved with fourth-order time-stepping methods. After transforming the equation to a system of ODEs, the linear operator is not diagonal, but we can implement the methods such as diagonal case which reduces the CPU time. Comparing numerical solutions with analytical solutions demonstrates that those methods are accurate and readily implemented. Also we investigate the conservation of mass for Bq equation.     

Solitons and Their Arrays: From Quasi 1D Conductors to Stripes

We suggest a short review of literature on various solitonic lattices and individual solitons in quasi one-dimensional conductors. This information seems to be quite relevant to topics of stripes and their melted phases correspondingly. We shall quote also the latest experiments, which access solitons as elementary excitations in organic conductors and in charge density waves. We shall outline a theory for ordered phases, where solitons should acquire forms of combined topological configurations (kink-roton complexes). The extension of this picture to cuprates allows interpretation of the latest STM observations on local rod-like structures.     

Mechanism of multiple pulse formation in the normal dispersion regime of passively mode-locked fiber ring lasers

We identify the spectral gain filtering as a mechanism of multiple pulse formation in a fiber laser passively mode-locked through nonlinear polarization rotation operating in the normal dispersion regime. A correlation is theoretically established between the spectral gain bandwidth and the possibility for the laser to deliver several pulses by cavity round-trip: narrow spectrum favours multiple pulsing. Moreover the model allows to show that spectral loss or gain filtering are equivalent with respect to their consequences on the multiple pulsing regime. Experimental results obtained with an erbium-doped fiber laser and an ytterbium-doped fiber laser confirm the theoretical calculations. In addition, an indirect confirmation of the influence of the spectral filtering is proposed using an experimental setup involving a unique laser.     

Wavelet Beam Propagation Method for Study the Integrated Optical Waveguide

A new numerical technique based on the wavelet derivative operator is presented as an alternative to BPM to study the integrated optical waveguide.The wavelet derivative operator is used instead of FFT/IFFT or finite difference to calculate the derivatives of the transverse variable in the Helmholtz equation.Results of numerically simulating the injected field at z=0 are exhibited with Gaussian distribution in transverse direction propagating through the two dimensional waveguides(with linear and/or nonlinear refractive index),which are similar to those in the related publications.Consequently it is efficient and needs not absorbing boundary by introducing the interpolation operator during calculating the wavelet derivative operator.The iterative process needsfewer steps to be stable.Also,when the light wave meets the changes of mediums ,the wavelet derivative operator has the adaptive property to adjust those changes at the boundaries.