共查询到20条相似文献,搜索用时 109 毫秒
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为了探索初始1阶相位调制对高斯光脉冲光纤中长距离传输特性的影响规律,从光纤中的非线性光演化方程出发,采用分步傅里叶算法,数值研究了初始1阶相位调制的高斯光脉冲在光纤中传输时的形状、幅度、时间轨道的演化特性。结果表明,高斯脉冲在长距离传输中,一方面其幅度呈现出衰减的振荡行为,另一方面其时间轨道则因为1阶相位调制的存在而发生直线平移;直线平移的大小和方向分别取决于相位调制参量的绝对值和正负号。该工作可扩展非孤子脉冲的长距离传输特性研究,并可用于脉冲时间轨道的直线调控。 相似文献
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高斯脉冲在色散缓变光纤中传输特性的研究 总被引:6,自引:2,他引:4
应用变分法,研究了高斯脉冲在色散缓变光纤中的传输特性,导出了高斯脉冲参数的演化方程组.在此基础上,讨论了色散缓变和初始啁啾对脉冲宽度的影响. 相似文献
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采用分步傅里叶方法数值研究了线性频率啁啾对高斯光脉冲在凸形色散分布平坦光纤中产生超连续(SC)谱的影响,并与啁啾双曲正割脉冲产生SC谱的情况进行了比较.结果表明:无啁啾高斯光脉冲的SC谱达到200 nm以上,其特性优于双曲正割脉冲的SC谱;获得最佳SC谱所需光纤长度随啁啾参量C增加而缩短;负啁啾时的SC谱特性劣于正啁啾时的特性,2种情况下的SC谱特性均劣于无啁啾时的SC谱特性,SC谱特性的劣化程度随|C|的增加而增大;在最佳SC谱对应的传输距离附近,高斯脉冲频谱质心随C的增加而红移且红移速度逐渐增加,比双曲正割脉冲的红移大且红移速度增加;高斯脉冲方均根频谱和脉宽随传输距离和随C增加逐渐展宽且展宽速度逐渐加快,比双曲正割脉冲的相应参量展宽得快且宽. 相似文献
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当电偶极子以高斯脉冲形式随时间振荡时,辐射出的电磁场可以用来描写非缓变包格近似条件下单周期超短脉冲光束在自由空间中的传输特性。利用复点源模型,通过分析和计算,我们得出它的传输特性。第一,在空间传输过程中,单周期超短脉冲高期光束能流密度基本保持高斯函数不变,振幅大小随不同的z平面振荡。第二,单周期超短脉冲光束在真空中主要以光速c沿z方向传输。在传输过程中,脉冲宽度保持不变,脉冲形状演变成不对称。能流密度不再随时间作简谐振荡,它的振幅构成一个高斯形状的包络。 相似文献
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光脉冲特性测量和分析的新方法 总被引:1,自引:0,他引:1
文章给出并采用了光脉冲特性分析新方法,对10 GHz光脉冲在色散平坦光纤中的线性传输前后的时域波形、相位和时间带宽积等作了深入研究,并与数值计算得到的双曲正割和高斯光脉冲线性传输特性作了比较,对光脉冲的时域波形、啁啾等作出了更准确的判断,进一步证实了光脉冲的二次谐波-频率分辨光学门测量及其分析新方法的可靠性和准确性. 相似文献
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借助脉冲的等效时间复参数讨论了Sech型光脉冲通过光纤一光栅对系统后的传输和变换特性,给出了脉冲压缩的最佳条件,为处理非高斯型光脉冲经过线性系统的传输提供了一种有效的方法。 相似文献
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基于光子晶体光纤(PCF)中脉冲演变遵循的非线性演化方程,用数值方法研究了反常色散情形下PCF中脉冲初始啁啾对超连续谱产生的影响,探讨了利用脉冲啁啾控制超连续谱产生的方法。结果表明:正、负啁啾均使谱展宽的速率变小,尤其是负啁啾情形,展宽速率更小,说明啁啾对谱展宽是不利的;在一定的初始条件下,光谱展宽存在一个最佳光纤长度,在这个长度处,光谱展宽最大,进一步增加光纤长度,谱宽基本保持不变;相对于变换极限脉冲来说,初始正、负啁啾脉冲对应的最佳光纤长度分别缩短和延长。 相似文献
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G. M. Strelkov 《Journal of Communications Technology and Electronics》2008,53(9):1034-1043
Analytic solution of the problem on propagation of a frequency-modulated radio pulse in cold isotropic collisional plasma is presented. The solution does not involve the Fourier integral and is not restricted to the distance of propagation or to the a priori choice of the shape of the initial pulse envelope. Rectangle pulses with linear and V-shaped frequency modulation and a trapezoidal pulse with linear frequency modulation are considered. The obtained solution is applied to analysis of distortions of such pulses during propagation along an ionospheric path. It is shown that the solution is efficient in the analysis of the uncertainty function of a propagating pulse 相似文献
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Shin Hong Sreenivashiah I. Ishimaru A. 《Antennas and Propagation, IEEE Transactions on》1977,25(6):822-828
The theory of plane wave pulse propagation through a random medium, under the forward-scattering assumption is presented. Since pulse propagation characteristics are determined by two-frequency mutual coherence functionGamma , a set of normalized curves is given forGamma for different propagation parameters (operating frequency, propagation distance, turbulence strength or density of scatterers, etc.). From the curves one can obtain the coherence bandwidth of a wave for a variety of situations. A received pulse form due to an input delta function is given in a normalized form which is applicable to the whole range of strong fluctuation. The results are applied to optical pulse propagation in dense clouds. It is shown that the high data rate optical pulse communication through clouds may be limited due to a narrow coherence bandwidth of the order of megahertz. A good agreement between the theoretical prediction and the available experimental data has been demonstrated for both the received pulse shapes and the pulse durations of an optical pulse in clouds. 相似文献
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We propose the sub-picosecond chirped soliton pulse propagation in concave-dispersion-flattened fibers(CDFF).The effects of pulse characteristics and the fiber dispersion parameters on propagation characteristics of the chirped soliton pulse are numerically investigated in the CDFF by the split-step Fourier method(SSFM).The unchirped soliton pulse can stably propagate with unchanged pulse width in the CDFF.The temporal full width at half maximum(FWHM) of the chirped soliton performs a damped oscillation with the increase of propagation distance.The period and amplitude of theoscillation increase with the increase of the chirp parameter |C|.The effect of high-order dispersion(β3-β6) on soliton propagation characteristics can be neglected.The soliton pulse slightly broadens with the increase of propagation distanceand still maintains soliton characteristics when the fiber loss(ATT) is further considered.The variation of root-meansquare(RMS) spectral width with propagation distance is opposite to that of the temporal width.The output spectrum of soliton has a single peak for the unchirped case,while has multi-peak for chirped case.The temporal width of the soliton obviously increases with the increase of the initial width,decreases with the increase of dispersion peak D0 of the fiber,and slightly increases with the decrease of dispersion coefficients k1 and k2 of the fiber. 相似文献
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Jiying Huang Wang He Shuhong Gong 《Journal of Infrared, Millimeter and Terahertz Waves》2007,28(10):889-899
When a pulse wave propagates through fog, the effects of distortion, being severer at millimeter wave band, is caused by fog because of its dispersive property. The transfer function of a pulse signal is obtained by the theory of radio wave propagation; the complex envelope is deduced by the solution of Fourier integral. The broadening and compressing effects of a pulse wave are discussed. The variations of distortion effects with pulse-width, propagation distance and visibility of fog are found. As an example, the simulating and calculating results of distortion effects for Gaussian pulse at millimeter wave band are given. 相似文献