共查询到20条相似文献,搜索用时 31 毫秒
1.
采用解析方法,在考虑材料损耗和色散的情况下,详细研究了无啁啾高斯脉冲和啁啾高斯脉冲在半导体光放大器中传输的物理过程,分析了强度增益、脉冲宽度和频率啁啾与线宽增强因子、色散系数、小信号增益特征参数及初始啁啾之间的关系。结果表明:当输入变换极限的高斯脉冲时,色散会引起增益压缩,脉冲展宽和频率啁啾;同样情况下,线宽增强因子越大,脉宽加宽越明显,输出脉冲啁啾越大,且随着线宽增强因子的增大,输出脉冲啁啾极大值向特征参数值较小的一边移动。当输入啁啾高斯脉冲时,初始脉冲啁啾越大,增益压缩越明显,啁啾系数为正时,脉冲单纯展宽,输出啁啾随特征参数的增大而逐渐减小,啁啾系数为负时,初始啁啾与群速度色散导致的啁啾相互竞争,致使脉冲先被压缩后被展宽;脉冲最窄处对应的特征参数随线宽增强因子的增大而先增大后减小,输出啁啾随特征参数的增大而经历振荡后趋于平稳。 相似文献
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Fernández A Jespersen K Zhu L Grüner-Nielsen L Baltuška A Galvanauskas A Verhoef AJ 《Optics letters》2012,37(5):927-929
Although femtosecond microjoule Yb-fiber systems are attractive because of a straightforward power scalability, they inherently suffer from a lowered pulse fidelity as a result of complex dispersion and nonlinearity management. Here, we present an integrated Yb-fiber system delivering high-fidelity microjoule pulses compressible down to 160 fs. The system uses a dispersion compensating fiber stretcher that is specially designed to match the dispersion of a 1480 lines/mm grating compressor. Performance analysis suggests the further possibility of scaling the pulse energy to tens of microjoules without pulse quality deterioration using this dispersion management scheme. 相似文献
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皮秒脉冲在色散缓变光纤中的孤子效应压缩 总被引:15,自引:4,他引:11
本文给出了描述皮秒脉冲在色散缓变单模光纤中孤子效应压缩过程的数学模型。通过数值求解,首次对该孤子效应压缩进行了全面的计算和分析。结果表明,与常规光纤相比,采用色散缓变程度合适的光纤压缩皮秒脉冲,不仅能显著地提高压缩后脉冲的峰值功率和脉冲压缩比,而且能有效地消除压缩后脉冲的次峰和脉座。对于确定的脉冲输入,发现,当光纤的色散缓变程度取某一最佳值时,能获得最佳的压缩效果。进一步研究表明,色散的这一最佳变 相似文献
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A. Efimov M.D. Moores B. Mei J.L. Krause C.W. Siders D.H. Reitze 《Applied physics. B, Lasers and optics》2000,70(7):S133-S141
Minimizing residual frequency dispersion that accompanies pulse stretching, amplification, and recompression is an important consideration in ultrashort chirped-pulse amplifiers. Here we show how an adaptive learning algorithm can be used in conjunction with a pulse shaper to compensate for higher-order and nonlinear dispersion in a chirped-pulse amplifier. Using spectral blueshifting as a sensitive diagnostic for pulse shape, we implement a 'learning loop' comprised of the pulse shaper, strong field laser ionization, and a genetic algorithm to minimize dispersion through the amplifier. We verify our optimization results using frequency-resolved optical gating (FROG) measurements and also show theoretically and experimentally that spectral blueshifting is indeed a sensitive diagnostic for pulse shape, and specifically, for higher-order dispersion. 相似文献
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M. Baumgartl B. Orta? J. Limpert A. Tünnermann 《Applied physics. B, Lasers and optics》2012,107(2):263-274
We report on a systematic study of an environmentally stable mode-locked Yb-doped fiber laser operating in the chirped-pulse regime. The linear cavity chirped-pulse fiber laser is constructed with a saturable absorber mirror as nonlinear mode-locking mechanism and a nonlinearity-free transmission-grating-based stretcher/compressor for dispersion management. Mode-locked operation and pulse dynamics from strong normal to strong anomalous total cavity dispersion in the range of +2.5 to ?1.6 ps2 is experimentally studied. Strongly positively chirped pulses from 4.3?ps (0.01?ps2) to 39?ps (2.5?ps2) are obtained at normal net-cavity dispersion. In the anomalous dispersion regime, the laser generates average soliton feature negatively chirped pulses with autocorrelation pulse durations from 0.8?ps (?0.07 ps2) to 3.9?ps (?1.6 ps2). The lowered peak power due to the pulse stretching allows one to increase the double pulse threshold. Based on the numerical simulation, different regimes of mode locking are obtained by varying the intra-cavity dispersion, and the characteristics of average soliton, stretched-pulse, wave-breaking-free and chirped-pulse regimes are discussed. 相似文献
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负折射介质中三阶非线性色散项对超短脉冲传输的影响 总被引:1,自引:1,他引:0
采用分步傅里叶法研究了三阶非线性色散项对超短脉冲传输的影响.通过模拟数值计算得出,在德鲁德模型频率选取的一定范围内,三阶非线性色散项对超短脉冲传输所造成的影响是不可忽略的.结果表明:三阶非线性色散项系数取负值时,在正常色散区超短脉冲不对称展宽,脉冲中心向前沿偏移;在零色散点超短脉冲不对称展宽程度加剧并在脉冲前沿形成振荡,脉冲中心向前沿偏移;在反常色散区超短脉冲不对称变窄,脉冲中心仍向前沿偏移. 相似文献
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We investigate the ultrashort pulse propagation through a linear gas medium by direct solution of the wave equation beyond the often used lowest orders of the dispersion approximation and the assumption of a slowly varying envelope. The dispersion effects and the effective absorption of the pulse energy by the medium are shown to result in a strong dispersive broadening of the initial pulse in the time and space domains. New features of the polarization response of the medium resulting from essentially nonadiabatic ramps of the pulse envelope are found. The possibility of using the two-pulse experimental scheme to partly compensate for the dispersion is discussed. 相似文献
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The dynamic evolution of ultrafast high-intensity pulses with a 100 fs half-width at 1/e intensity point based on the silicon-on-insulator (SOI) strip nanowaveguides is considered and investigated numerically under
the condition of anomalous group-velocity dispersion (GVD) regime. For ultrafast high-intensity pulses propagating in millimeter-long
SOI nanowaveguides, the interplay between the dispersion and nonlinear effects such as the two-photon absorption, free-carrier
absorption, free-carrier dispersion, and self-phase modulation has to be taken into account, which results in the significant
optical wave breaking phenomenon that occurs near the pulse leading edge for an unchirped Gaussian pulse in the anomalous
GVD regime. However, when the input Gaussian pulse with linear up-chirp is introduced, the position of the optical wave breaking
shifts from the leading pulse edge to its trailing edge along the several millimeters-long SOI nanowaveguides. 相似文献
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By using a frequency-modulated Gaussian pulse as an example, it is shown within the framework of the linear model taking into account the second-order dispersion effects that the presence of the imaginary part of the dispersion parameter of the group velocity substantially affects the pulse dynamics in a single-mode optical fiber with gain. Absorption insignificantly influences the dispersion characteristics of the fiber and its transformation properties. The possibility of the realization of “supercompression,” under which the pulse duration τp → 0, as well as of compression of a pulse without initial frequency modulation, is revealed. It is shown that in these fibers, the propagation of the pulse peak with a faster-than-light velocity and the wavefront reversal effect are possible. 相似文献
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光纤中基于交叉相位调制的超短光脉冲串的产生 总被引:4,自引:1,他引:3
提出一种在单模光纤正常色散区由连续波产生超短光脉冲串的新方法,即让连续波和一个波长位于光纤正常色散区的调制脉冲串在光纤中同时传输,交叉相位调制效应和群速度色散效应的相互作用能使连续波演化成一串超短光脉冲,其脉冲宽度比调制脉冲串中的脉宽要小得多,本文还通过计算机模拟,对这一方法进行了全面的考察和分析。结果表明,该方法不仅实用,而且可取得较好的效果。 相似文献
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We demonstrate a passively mode-locked ring fiber laser operating in the stretched-pulse regime. The ring cavity model is constructed with standard single-mode fiber and dispersion delay line for dispersion management. Here, all-solid Yb-doped photonic bandgap fiber is used as the dispersion delay line and provides laser gain simultaneously. As the all-solid Yb-doped photonic bandgap fiber has large third-order dispersion, it is necessary to study its impact on the stretched-pulse operation. The presence of the third-order dispersion reduces pulse quality because of the relatively small group velocity dispersion. To improve the pulse quality, a spectral filter is employed in the model. The simulation results show that spectral filtering could improve the pulse quality and shorten the pulse duration. Meanwhile, the optimum filter bandwidth is studied. 相似文献
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Optical pulse compression using high-order dispersion compensation is proposed and theoretically analyzed. Firstly, the required
dispersion profile for the high-order dispersion compensation is derived, according to the linear chirp and the nonlinear
chirp of a phase-modulated continuous-wave (CW) laser source. With the use of the high-order dispersion compensation, such
as the combination compensation of the second order dispersion (SOD) and the fourth order dispersion (FOD), an efficient pulse
compression having a less time-bandwidth product and a greater peak power is realized. A sampled fiber Bragg grating (FBG)
with both the SOD and the FOD is then designed using the equivalent chirp and the reconstruction algorithm. Finally, in the
numerical simulation an optical pulse with a time-bandwidth product of 0.79 is generated via high-order dispersion compensation
that is performed by using the sampled FBG. 相似文献
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Dispersion measurements in new ‘Selfoc’ fibres have been performed using a Ga Al Aslaser as light source. A strong influence of the laser/fibre coupling on the pulse response was observed. The measured pulse broadening from 0.6 ns (the half-peak power width of the laser output pulse) to 8 ns after a transmission length of 700 m is much larger than the previously reported value. Over this length the dispersion was found to increase linearly. The measured refractive index profile and that calculated from the observed dispersion are in good agreement. 相似文献
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文章根据平稳重调脉冲(SRP)在梳状光纤(CPF)结构中的压缩原理,对色散渐减光纤(DDF)的色散特性进行设计,结果发现该色散渐减光纤的色散特性呈线性递减.对于平稳重调脉冲其压缩比与功率比等于光纤始末两端二阶色散系数的比值.当色散渐减光纤的斜率足够小时,无啁啾基阶孤子可以近似为平稳重调脉冲,当色散渐减光纤的色散斜率较大时,无啁啾基阶孤子不能近似为平稳重调脉冲.当基阶孤子带有与光纤色散斜率成正比的线性啁啾时,脉冲的压缩比与功率比更接近于光纤始末两端二阶色散系数的比值.说明带有线性啁啾的基阶孤子比不带啁啾的基阶孤子更接近于平稳重调脉冲.
关键词:
平稳重调脉冲(SRP)
梳状光纤(CPF)
色散渐减光纤(DDF)
色散递减表达式 相似文献
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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. 相似文献