受激喇曼散射对自相似脉冲产生的影响

研究了在受激喇曼散射与三阶色散共同作用下,自相似脉冲在具有正常色散的色散渐减光纤中的演化情况.结果表明:在同一个传输距离上,当考虑受激喇曼散射与三阶色散的共同影响时,脉冲中心的不对称特性相对好转;产生中心漂移与边缘振荡较只有三阶色散作用时要减弱,啁啾仍然具有很强的线性特性,但是线性范围减小,导致频谱的窄化以及对接下来自相似脉冲的压缩产生了不利影响;而且光纤长度的延长并没有起到展宽啁啾线性范围的效果,反而导致严重的啁啾非线性;因此对脉冲进行压缩后,压缩脉冲质量较不考虑受激喇曼散射时要差.     

色散渐减光纤中自相似脉冲传输特性研究

研究了在高阶色散影响下,自相似脉冲在具有正常色散的色散渐减光纤中的演化情况.结果表明:当考虑高阶色散的影响时,脉冲的啁啾仍然具有很强的线性特性,只是中心变得不对称,产生中心漂移.这种啁啾特性使得自相似脉冲在时域中的抛物线形状产生畸形,导致了脉冲峰向一边延迟,并使脉冲的中心位置漂移,同时伴随着脉冲边沿的振荡.但是通过采用色散补偿技术,自相似脉冲强的线性啁啾仍然可以得到高质量的飞秒量级压缩脉冲,与忽略三阶色散影响时得到的压缩脉冲的脉宽近似相等.     

Higher-order effects on self-similar parabolic pulse in the microstructured fibre amplifier

By considering higher-order effects, the properties of self-similar parabolic pulses propagating in the microstructured fibre amplifier with a normal group-velocity dispersion have been investigated. The numerical results indicate that the higher-order effects can badly distort self-similar parabolic pulse shape and optical spectrum, and at the same time the peak shift and oscillation appear, while the pulse still reveals highly linear chirp but grows into asymmetry. The influence of different higher-order effects on self-similar parabolic pulse propagation has been analysed. It shows that the self-steepening plays a more important role. We can manipulate the geometrical parameters of the microstructured fibre amplifier to gain a suitable dispersion and nonlinearity coefficient which will keep high-quality self-similar parabolic pulse propagation. These results are significant for the further study of self-similar parabolic pulse propagation.     

高阶色散效应常系数Ginzburg-Landau方程自相似脉冲演化的解析分析

采用自相似分析方法,基于常系数高阶色散的Ginzburg-Landau方程,通过分离变量法得出了高阶色散效应自相似脉冲演化的解析解,给出了自相似脉冲的振幅、相位、啁啾以及脉冲宽度的一般表达式.研究表明,在增益光纤的二阶正常色散区域,同时考虑高阶色散和增益色散双重效应影响下演化的自相似孤子脉冲仍然保持线性啁啾;振幅解析解的三阶色散效应显著.这与数值计算的结果非常一致. 关键词： 三阶色散 Ginzburg-Landau方程 自相似脉冲 二阶正常色散     

Analytical self-similar solutions of the Ginzburg-Landau equation with three-order dispersion effect

Based on the technique of the symmetry reduction, we find the asymptotic self-similarity analytical resolutions from the constant coefficient Ginzburg-Landau equation considering both influences of the thirdorder dispersion and gain dispersion on the evolution of pulses. We have obtained the self-similar pulse amplitude function, phase function, strict linear chirp function, and the effective temporal pulse width. Numerical simulations show qualitative agreement with these theoretical results.     

Ported from Self-Similar Analytic Solutions of Ginzburg--Landau Equation with Varying Coefficients

Employing the technique of symmetry reduction of analytic method, we solve the Ginzburg-Landau equation with varying nonlinear, dispersion, gain coefficients, and gain dispersion which originates from the limiting effect of transition bandwidth in the realistic doped fibres. The parabolic asymptotic self-similar analytical solutions in gain medium of the normal GVD is found for the first time to our best knowledge. The evolution of pulse amplitude, strict linear phase chirp and effective temporal width are given with self-similarity results in longitudinal nonlinearity distribution and longitudinal gain fibre. These analytical solutions are in good agreement with the numerical simulations. Furthermore, we theoretically prove that pulse evolution has the characteristics of parabolic asymptotic self-similarity in doped ions dipole gain fibres.     

Interaction between parabolic pulses in a dispersion-decreasing fiber

The properties of the self-similar parabolic pulses interaction in a dispersion-decreasing optical fiber with normal group-velocity dispersion are firstly investigated in our paper. We find that two parabolic pulses separated by a time-delay create oscillation with a sinusoidal fit at the beginning of their overlap, and then further evolve into a train of asymptotic dark solitons. Additionally, outside the overlap regime, the evolution is equal to a single pulse’ propagating behavior. The chirp after interaction in the parabolic pulses still allows for efficient and high-quality pulse compression.     

Third-order dispersion role on parabolic pulse propagation in dispersion-decreasing fiber with normal group-velocity dispersion

Parabolic pulse propagation in a dispersion-decreasing fiber with normal group velocity dispersion (ND-DDF) has been studied when the third-order dispersion (TOD) is included. The results show that the characteristic of exact self-similarity and linear chirp will be lost due to the third-order dispersion. However, by using the dispersion compensation technique, one can obtain efficient and high-quality compressed pulses. The analytic results have been confirmed using numerical simulations.     

光纤放大器中的自相似抛物脉冲

本文研究在含有增益色散、增益饱和、三阶色散、自频移、自陡峭等效应的光纤放大器中自相似抛物脉冲的产生和传输。结果表明,在渐近约束条件下,自相似脉冲的中心区域可用倒置的抛物脉冲来描绘,并且它的有效脉宽和功率都是线性增长的,而峰值振幅和频谱宽度保持常量。数值模拟结果与理论预期符合的非常好,这表明:在光纤放大器中,在适当的条件下初始输入脉冲可自相似地演化为抛物脉冲。     

掺镱光纤放大器中自相似脉冲传输特性研究

研究了高阶色散和增益色散影响下,自相似脉冲在掺镱光纤放大器中的传输特性.从解析求解和数值模拟两方面分别阐述了初始脉冲能量、三阶色散和偶极子驰豫时间对脉冲传输质量的影响.结果表明,当传输考虑三阶色散效应时,伴随着脉冲啁啾非线性区域的扩大,啁啾中心随着色散系数取值的大小和正负前、后移动,脉冲峰向一侧延迟,中心位置发生漂移.增益色散对脉冲放大起到滤波作用,对自相似脉冲具有压窄效应.证实了具有一定驰豫时间的增益介质能够维持自相似孤子波的稳定传输.     

利用光纤-光栅对1.06μm皮秒光脉冲压缩

本文报道了利用光脉冲在10m单模光纤中传播所产生的自相位调制(SPM)、互相位调制(XPM)、群速色散(GVD)和受激喇曼散射(SRS)的共同作用,实现光脉冲光谱和时间加宽,经光栅对线性啁啾补偿后,将脉宽15ps的1.06μm光脉冲压缩至小于6ps,能量大于100nJ,压缩比>2.5。     

Generation of the self-similar parabolic pulses by designing comb-like profiled dispersion fiber based on alternately arranged single-mode fibers and dispersion-shifted fibers

Based on the nonlinear Schrödinger equation and the linearly chirped parabolic pulse generation in the dispersion decreasing fiber with normal dispersion, a novel scheme for the generation of the self-similar parabolic pulse via a comb-like profiled dispersion fiber with normal group-velocity dispersion has been proposed and the corresponding model is established. We study, analytically and numerically, the evolution of the self-similar parabolic pulse in comb-like profiled dispersion fiber with dispersion profile close to that of the dispersion decreasing fiber, and the influence of different initial energies and pulse widths on the linearly chirped parabolic pulse formation in the comb-like profiled dispersion fiber. The results show that the evolution of the self-similar parabolic pulses can realized in the comb-like profiled dispersion fiber, the results of which are in good agreement with these of the dispersion decreasing fiber, and the best-matched scheme of designing and optimizing comb-like profiled dispersion fiber will help to obtain the ideal similaritons.     

色散渐减光纤中Ginzburg-Landau方程的自相似脉冲演化的解析解

采用对称约简的分析方法，得出了变系数Ginzburg-Landau方程的抛物渐近自相似脉冲解析解的一般表达式.给出了二阶色散系数纵向双曲型变化和纵向指数型变化的色散渐减光纤中自相似脉冲的振幅、啁啾以及脉冲宽度的具体形式，并与数值解进行了对比，其结果符合得很好.从而证实了稀土元素掺杂的色散渐减光纤中，在增益色散因子的影响下，脉冲的演化具有抛物型自相似特性.     

Analytic solutions of self-similar pulse based on Ginzburg-Landau equation with constant coefficients

Based on the constant coefficients of Ginzburg-Landau equation that considers the influence of the doped fiber retarded time on the evolution of self-similar pulse, the parabolic asymptotic self-similar solutions were obtained by the symmetry reduction algorithm. The parabolic asymptotic amplitude function, phase function, strict linear chirp function and the effective temporal pulse width of self-similar pulse are given in this paper. And these theoretical results are consistent with the numerical simulations. Supported by the Natural Science Foundation of Guangdong Province of China (Grant No. 04010397)     

Parabolic pulse generation by use of a dispersion-decreasing fiber with normal group-velocity dispersion

We propose a new method for generating a parabolic pulse by use of a dispersion-decreasing fiber with normal group-velocity dispersion. When a hyperbolic dispersion-decreasing structure is employed, the pulse evolves into a linearly chirped pulse with an exact parabolic intensity profile without radiating dispersive waves. The highly linear chirp in the parabolic pulse allows for efficient and high-quality pulse compression.     

类明孤子在光纤中传输特性的变分研究

应用变分法,研究了微扰对类明孤子在光纤巾非线性传输特性的影响,导出了类明孤子脉冲参量演化的动力学方程。它统一了在单模光纤、色散缓变光纤或色散控制光纤中类明孤子脉冲参量演化的动力学方程。在此基础上,计算了色散缓变光纤中的线性高阶色散微扰。结果表明：线性高阶色散对类明孤子脉冲的位置和相位有影响,而对振幅、宽度和啁啾没有影响;光纤色散缓变对类明孤子脉冲的所有参量均有影响。     

Dynamics of self-similar light pulses of limiting pulse width and energy in a fiber laser

We investigate dynamics of the formation of high-power ultrashort self-similar light pulses (similaritons) in a fiber laser in the regime of positive dispersion. The physical factors limiting the energy and the pulse width of such pulses are revealed. We specify regimes where a laser system based on an ytterbium-doped fiber can generate self-similar pulses with an energy of about 80 nJ compressible to a pulse width of about 150 fs through extracavity linear chirp compensation.     

线性啁啾光脉冲在具有纵向增益光纤中的自相似传播研究

非线性薛定谔方程是光脉冲在光纤中传播时所遵循的基本方程.本文利用分步傅里叶方法从数值结算的角度研究了具有线性啁啾的光脉冲在具有横向增益光纤中的自相似传播特性.研究表明:当群速度色散系数和光脉冲的啁啾系数符号相同时,由于在传播过程中自相位调制和群速度色散分别起主要作用,不论何种形式的光脉冲在传输过程中均会受到压缩,但随着传播距离的增加压缩的光脉冲会展宽;埃尔米特高斯输入和正弦输入在传播过程中的光强分布是对称的,拉盖尔高斯输入在传播过程中会发生能量交换而表现出明显的偏转;当群速度色散系数和光脉冲的啁啾系数符号不相同时,在传播过程中群速度色散始终起主要作用,脉冲一直展宽.这些研究结论可能为未来光纤压缩器、光纤放大器以及新型THz调制波源的制备提供新的理论基础和方法.     

线性啁啾光脉冲在具有纵向增益光纤中的自相似传播研究

非线性薛定谔方程是光脉冲在光纤中传播时所遵循的基本方程.本文利用分步傅里叶方法从数值结算的角度研究了具有线性啁啾的光脉冲在具有横向增益光纤中的自相似传播特性.研究表明:当群速度色散系数和光脉冲的啁啾系数符号相同时,由于在传播过程中自相位调制和群速度色散分别起主要作用,不论何种形式的光脉冲在传输过程中均会受到压缩,但随着传播距离的增加压缩的光脉冲会展宽;埃尔米特高斯输入和正弦输入在传播过程中的光强分布是对称的,拉盖尔高斯输入在传播过程中会发生能量交换而表现出明显的偏转;当群速度色散系数和光脉冲的啁啾系数符号不相同时,在传播过程中群速度色散始终起主要作用,脉冲一直展宽.这些研究结论可能为未来光纤压缩器、光纤放大器以及新型THz调制波源的制备提供新的理论基础和方法.     

高非线性光纤产生自相似抛物线脉冲的特性研究

基于脉冲在光纤中传输所满足的非线性薛定谔方程,采用数值计算的方法对脉冲在高非线性光纤中演化成自相似抛物线脉冲的传输特性进行了研究。结果表明,脉冲在不同初始能量和啁啾参量的情况下,高非线性光纤产生自相似抛物线脉冲,且随着归一化长度的增大,脉冲的自相似指数从0.0796减小到0.0720。进一步的研究表明:啁啾高斯脉冲在光纤传输过程中,脉冲逐渐展宽,同时正啁啾越大,其自相似演化结果越差;参数N=8的正负啁啾脉冲分别演化成平顶自相似抛物线脉冲以及三角形脉冲。