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本文就群速度色散对非线性光纤环镜型OTDM解复用器的影响进行了理论与数值分析。首先给出了描述群速度色散与非线性效应之间相互作用的耦合非线性薛定谔方程组,然后用分步傅立叶方法对该方程组进行了数值求解。经分析同,要达到一定的开关性能,孤子阶数,色散的正负,脉冲宽度及控制和信号脉冲之间的走离时间应满足一定的条件。 相似文献
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光参量效应中低阶色散对超短高斯脉冲展宽的影响 总被引:1,自引:1,他引:1
以宽度为50 fs的超短脉冲和负单轴晶体CsLiB6O10(CLBO)为例,对非线性光学晶体中低阶群速度色散(GVD)导致的超短高斯脉冲和超高斯脉冲的脉冲展宽进行了理论分析.在光参量相互作用过程中,对初始无啁啾和有啁啾调制的超短高斯脉冲的脉冲展宽机制和因素进行了数值计算,得出群速度色散导致超短脉冲的寻常光比非寻常光脉冲展宽更严重;波长越短,脉冲展宽越大;当晶体长度等于色散长度时,脉冲宽度增加为初始时的2倍,色散长度越短,超短脉冲展宽越明显. 相似文献
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群速度色散和高阶非线性效应是影响超强超短脉冲抽运下光参变放大能量转换效率的重要因素.为了提高光参变放大的能量转换效率,采用理论分析和数值计算的方法,模拟超强超短激光脉冲抽运下MgO:LiNbO3晶体中的光参变放大过程,得到了不同抽运功率密度、不同群速度色散条件下光参变放大的能量转换效率曲线,并且讨论了高阶非线性效应对和脉冲时间波形和频谱的影响.结果表明,群速度色散会使抽运光脉宽增加,功率密度降低;大功率密度抽运下高阶非线性效应的影响不可忽略,它会进一步减小能量转换效率,还会使信号光的频谱展宽,为了提高单位晶体长度的参变放大增益,可以通过引入初始啁啾来抵消群速度色散的影响. 相似文献
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光子晶体光纤中非线性传输的数值研究 总被引:1,自引:1,他引:0
数值模拟了飞秒激光脉冲在光子晶体光纤中的非线性传输过程,详细计算分析了自相位调制(SPM)、脉冲内拉曼散射(ISRS)、自陡峭(SS)以及群速度色散(GVD)、三阶色散(TOD)、四阶色散(FOD)对脉冲传输和频谱的影响。结果表明,在反常色散区,脉冲内拉曼散射以及三阶、四阶色散对频谱的展宽和脉冲的平滑都有着重要作用;而自陡峭是使高阶孤子分量产生分裂衰变,对光谱的不对称展宽有一定影响。 相似文献
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皮秒正啁啾脉冲的孤子效应压缩 总被引:2,自引:0,他引:2
在近似求解非线性薛定谔方程、分析单模光纤负群速度色散区群速度色散和自相位调制效应所致频率啁啾对入纤正啁啾脉冲的调制压缩机理的基础上,定量计算了在光纤负色散区损耗对初始正啁啾皮秒脉冲孤子效应压缩的影响.结果表明:初始正啁啾改善了损耗对压缩参量的不良影响,遏制了最佳光纤长度的增加,增强了压缩效果,提高了压缩质量.选取适当的光纤长度和初始峰值功率,可望实现光学脉冲在单模光纤中的有效压缩. 相似文献
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The authors report the first experimental demonstration of high-frequency dark soliton generation through nonlinear conversion of a high-intensity beat signal in a +GVD dispersion decreasing fibre. High quality, 1.6 ps dark soliton generation at 100 GHz is obtained. The quality of the pulses and the stability of the trains are demonstrated by propagation through a 2.2 km span of +GVD dispersion shifted fibre (≃two soliton periods) 相似文献
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Chen X. Panoiu N. C. Hsieh I. Dadap J. I. Osgood R. M. 《Photonics Technology Letters, IEEE》2006,18(24):2617-2619
The dynamics of femtosecond (fs) pulse propagation in dispersion engineered silicon-on-insulator (SOI) photonic wires is investigated numerically. For fs pulses propagating in millimeter-long SOI waveguides, the interplay between nonlinear effects, group velocity dispersion (GVD), and the third-order dispersion (TOD) results in significant pulse reshaping. At the zero-GVD (ZGVD) wavelength, TOD causes strong pulse-shape asymmetry in both the temporal and spectral domains. In addition, in the anomalous GVD region near the ZGVD wavelength, soliton-like pulse dynamics is observed 相似文献
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Time-resolved numerical analysis of a nonlinear Sagnac interferometer switch (NSIS) reveals that the combined effects of group velocity dispersion (GVD), self phase modulation, cross phase modulation, and pump-probe walk-off seriously degrade switching performance when the soliton number N of the pump pulse is under 5. This means that the peak power of short pump pulses cannot be reduced to less than the critical value at N >5 to prevent the effect of GVD. This restriction is more severe for pump pulses in the anomalous dispersion region than for those in the normal dispersion region because of higher-order soliton compression. System designs for time-division demultiplexers that use NSISs and picosecond pump pulses generated by a laser-diode coupled to erbium-doped fiber amplifiers are discussed. It is found that 1:32 demultiplexing from 160 to 5 Gb/s and 1:8 demultiplexing from 80 to 10 Gb/s with a switching contrast of more than 60 are possible using diode-laser-pumped 1- and 2-ps pump pulses, respectively 相似文献
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We theoretically and experimentally studied the dispersion effects in an actively mode-locked inhomogeneously broadened laser. In the positive group velocity dispersion (GVD) region, the laser generates incoherent pulses. Self-phase modulation and resonant dispersion impede reduction of the pulse duration when the GVD is small or near zero. A single, stable, soliton-like pulse can be generated only when the GVD is within a certain range of negative values. When the negative GVD is too small, the laser generates only multiple soliton-like pulses because of excess gain filtering. When the negative GVD is too large, the soliton pulse-shaping process fails, and the laser generates only incoherent pulses due to insufficient gain filtering. In the experiment, we characterized an actively mode-locked inhomogeneously broadened Nd:silicate glass laser and confirmed this GVD dependence. The laser generated self-sustaining, soliton-like pulses as short as 77 fs. 相似文献
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具有高阶耦合色散系数双芯非线性光纤耦合器开关的数值分析 总被引:2,自引:1,他引:2
基于耦合非线性薛定谔方程(NLSE),利用分裂步长傅里叶方法(SSFM),研究了具有高阶耦合色散系数时,双芯非线性光纤耦合器中的传输和开关特性.模型中,一阶耦合色散系数的存在类似于群速度失配,二阶耦合色散系数类似于群速度色散,并且会对另一个纤芯中的信号产生线性互调制.研究表明当一阶耦合色散系数较小时,光脉冲仍能在二纤芯之间周期性耦合传输,并且表现出良好的开关特性,当一阶耦合色散系数增大时,脉冲耦合传输的周期性和陡峭的开关特性遭到破坏,光脉冲在传输中发生分裂;二阶耦合色散系数使耦合器的耦合长度减短,开关阈值功率增加,开关特性也变得更加陡峭. 相似文献
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Highly nonlinear bismuth-oxide fiber for supercontinuum generation and femtosecond pulse compression 总被引:1,自引:0,他引:1
Gopinath J.T. Shen H.M. Sotobayashi H. Ippen E.P. Hasegawa T. Nagashima T. Sugimoto N. 《Lightwave Technology, Journal of》2005,23(11):3591-3596
Highly nonlinear normally dispersive bismuth-oxide fiber shows promise for applications such as supercontinuum generation and femtosecond pulse compression in the telecommunications-wavelength range. To generate a wideband and flat supercontinuum spectrum, the balance between fiber nonlinearity and normal group velocity dispersion (GVD) is important. Highly nonlinear bismuth-oxide fiber exhibits a large nonlinearity due to the small effective area and nonlinear index of the host glass material. The fiber also has a relatively flat dispersion profile over a large wavelength range. Utilizing these features, we generate a smooth unstructured supercontinuum between 1200 and 1800 nm. This supercontinuum is passed through a grating pair, and pulses, originally of 150-fs length, are compressed to 25 fs. 相似文献
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The propagation of femtosecond laser pulses with wavelengths of 1550 nm, 1064 nm, 800 nm and 700 nm, respectively, which are
in the normal dispersion region of the nano-structured photonic crystal fiber (N-PCF) with interesting broadband normal dispersion
and highly nonlinear properties, is studied. For the effect of chirp variation mainly induced by group velocity dispersion
(GVD) and self-phase modulation (SPM), after propagation over a short length, the wave breaking occurs. Namely, oscillatory
structures are presented near pulse edges and sidelobes appear in the pulse spectrum. In the case of 800 nm, after the propagation
of 20 mm, a super flat spectrum is obtained. The bandwidth of the super flat spectrum is associated with the dispersion length
and the nonlinear length. By choosing N-PCF and laser pulse with appropriate parameters, a broadband super flat spectrum in
a short length can be achieved. 相似文献
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Group-velocity dispersion (GVD) compensation in in-line amplifier systems is evaluated from the viewpoint of improving the transmission distance. The nonlinear Schrodinger equation, which simulates signal propagation in optical fibers, is numerically evaluated to clarify the optimum configuration for GVD compensation. It is shown that the optimum amount of GVD compensation is about 100% of the GVD experienced by the transmitted signal. The optimum compensation interval is found to be a function of the bit rate, signal power, and dispersion parameter. For dispersion parameter values ranging from about -0.1 ps/nm/km to -10 ps/nm/km, and an amplifier noise figure of about 6 dB, the optimum compensation configuration can eliminate the GVD from in-line amplifier systems, thus improving transmission distances to those limited by self-phase modulation and higher-order GVD 相似文献