共查询到18条相似文献,搜索用时 203 毫秒
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光纤放大器中的自相似抛物脉冲 总被引:1,自引:1,他引:0
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。 相似文献
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受激喇曼散射对自相似脉冲产生的影响 总被引:2,自引:0,他引:2
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. 相似文献
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利用耦合非线性薛定谔方程(CNLSE)为非线性偏振旋转(NPE)锁模自相似光纤激光器建立了一种新的数值模型.模型中,用CNLSE描述脉冲在单模光纤中的传播,在增益光纤中同时考虑了增益带宽和增益饱和作用,用传输矩阵描述构成NPE锁模的光学元件.优化了腔内净色散和光纤长度等参数,模拟了脉冲在激光腔内的演化特性,得到了典型的自相似脉冲运行区域及特点.在最佳自相似脉冲运行区域内,得到了能量约为7 nJ、脉宽约11 ps、线性啁啾的抛物脉冲.比较了不同腔内净色散条件下输出脉冲的特点,给出了三阶色散对输出脉冲的影响.
关键词:
自相似脉冲
非线性偏振旋转锁模
耦合非线性薛定谔方程
数值模拟 相似文献
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以包含增益色散、增益饱和、三阶色散、自陡峭、自频移等高阶效应的光纤放大器为研究对象,对其产生渐近抛物型自相似脉冲的条件及传输特性进行了详细的讨论.结果表明,合理选择系统参数,在渐近约束条件下,可以获得不同振幅和脉宽大小的自相似脉冲;此外,非线性增益(或吸收)与非线性谱宽限制在自相似脉冲存在的范围内近似成线性比例关系,且脉冲的有效脉宽,功率,峰值振幅及能量的大小及增长速度也将随参数的变化面变化.相关结果将为实验中调节光纤放大器以及系统参数的选择提供一定的理论参考. 相似文献
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用实验和数值模拟两种方法研究了高非线性光子晶体光纤中飞秒激光脉冲的传输特性和超连续谱的产生机理,给出了抽运脉冲在三种不同中心波长情况下输出光谱展宽并形成超连续谱的实际测量及理论模拟结果.研究表明:在零色散波长抽运时,光谱展宽以自相位调制为主,同时三阶色散的影响明显,传输脉冲在时域内出现振荡次峰.而在反常色散区抽运时,光谱展宽的初期以自相位调制为主,随后根据抽运功率的不同孤子自频移、高阶光孤子的裂变和四波混频效应会逐渐增强,进而成为光谱展宽的主要原因.与此相应,在时域中能明显看到孤子的形成和红移,飞秒传输脉
关键词:
光子晶体光纤
高非线性光子晶体光纤
飞秒脉冲激光
超连续谱 相似文献
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利用掺镱双包层光纤放大器对百皮秒单脉冲(重复频率1 Hz)进行了放大实验,分析了其放大过程中自相位调制对脉冲时域和频域特性的影响.采用小芯径(纤芯直径6.5 μm)掺镱双包层光纤作为增益介质,研究了放大器中从小信号增益到增益深度饱和整个变化过程中自相位调制引起的频谱展宽效应,并分析了SPM引起的脉冲波形和频谱光强分布的变化.采用布喇格光纤光栅扫描方法观察了其光谱的变化,解决了单脉冲光谱不易测量的问题.结果表明:区别于无源光纤中的自相位调制效应,随着抽运功率的增加,百皮秒脉冲放大过程中增益饱和效应和自相位调制效应的共同作用,使脉冲频谱分裂成不对称双峰结构,且光强分布先向短波后逐渐向长波集中. 相似文献
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XU Lei YAO Minyu LI Yuhua WU Jian CHEN Minghua ZHANG Jianfeng ZHANG Hongming LOU Caiyun GAO Yizhi 《中国光学快报(英文版)》1999,8(4)
200 nm superconticnumm (SC) with high flatness (<3 dB) is demonstrated with subpicosecond optical pulses generated by a passively mode-locked figure-eight-laser. The evolution process of SC under different optical pumping power is observed experimentally. Three sequential evolution stages are found: (1) SC spectrum is asymmetrically broadened due to self-phase modulation (SPM) and group velocity dispersion (GVD). (2) When the broadened spectrum exceeds the zero dispersion point, cross phase modulation (XPM) and four wave mixing (FWM) will cause symmetrical spectrum broadening. (3) stimulated Raman scattering (SRS) causes the spectrum to broaden toward long wavelength quickly when pumping power is intense enough. 相似文献
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200 nm Supercontinuum Generated by Subpicosecond Optical Pulses and its Evolution Process Observation 总被引:1,自引:0,他引:1
XU Lei YAO Minyu LI Yuhua WU Jian CHEN Minghua ZHANG Jianfeng ZHANG Hongming LOU Caiyun GAO Yizhi 《Chinese Journal of Lasers》1999,8(4):289-293
Introduction Whenultrashortopticalpulseswithhighintensity(pumpinglight)areinjectedintodispersionshiftedfiber(DSF),duetothenonlineareffectsinfibersuchasselfphasemodulation(SPM),fourwavemixing(FWM),crossphasemodulation(XPM)andstimulatedRamanscatteri… 相似文献
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研究了皮秒抽运脉冲在正常色散平坦光纤中超连续谱的形成过程,分析了脉冲演化过程中光波分裂的产生及其所显示的四波混频对超连续谱特性的影响.结果表明:脉冲初期光谱展宽由自相位调制效应主导,此后由于光谱中心区域能量在色散作用下不断向旁瓣转移,自相位调制效应逐渐减弱而四波混频作用增强,光谱会再度显著展宽.超连续谱的噪声特性与光谱演化状态密切相关,是光谱特征结构对抽运脉冲强度噪声响应的动态表征.
关键词:
正常色散平坦光纤
自相位调制
四波混频
超连续谱 相似文献
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We report experimental and theoretical investigations of the evolution of super-broadened spectrum generation by intense 50-fs pulses propagating in bulk fused silica. Based on good agreement between the experimental results and numerical simulations, a mechanism of supercontinuum generation (SCG) is proposed. At first, both self-phase modulation (SPM) and stimulated Raman scattering (SRS) contribute substantially but slowly to the broadening before filament formation takes place. After filamentation, a plasma grows rapidly and asymmetric spectral broadening results in a blue-shifted spectrum extending to about 400 nm. A time-resolved experiment of the SCG was also performed using a double-pump technique. The temporal behavior suggests that the vibrational mode excited by the stimulated Raman process by the first pulse contributes to the occurrence of self-focusing. PACS 42.65.Re; 42.25.Bs 相似文献
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Efficient numerical modelling of the power, spectral and statistical properties of partially coherent quasi-CW Raman fiber laser radiation is presented. XPM between pump wave and generated Stokes wave is not important in the generation spectrum broadening and XPM term can be omitted in propagation equation what sufficiently speeds-up simulations. The time dynamics of Raman fiber laser (RFL) is stochastic exhibiting events several times more intense that the mean value on the ps timescale. However, the RFL has different statistical properties on different time scales. The probability density function of spectral power density is exponential for the generation modes located either in the spectrum centre or spectral wings while the phases are distributed uniformly. The pump wave preserves the initial Gaussian statistics during propagation in the laser cavity. Intense pulses in the pump wave are evolved under the SPM influence and are not disturbed by the dispersion. Contrarily, in the generated wave the dispersion plays a significant role that results in stochastic behavior. 相似文献
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Efficient frequency conversion of 5 ps-pulses from a cavity dumped Rh6G-dye laser by stimulated-Raman-scattering (SRS) into the first and second Stokes order has been achieved. The simulateneously produced asymmetric spectrical broadening of the pump pulses leads to double peaks in the Raman spectrum. By means of spectrally resolved cross-correlation measurements with 2 ps pulses from a second synchronized dye laser, the relative arrival time of the various spectral components is measured. Furthermore it is shown that the effect of a reduction of the pump peak power by SPM is partially compensated by the temporal broadening of the pump pulses leading to a longer interaction length for SRS. 相似文献
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We propose and experimentally demonstrate a scheme of high-Q microwave photonic filter (MPF) using the techniques of self-phase modulation (SPM) spectrum broadening and third-order dispersion (TOD) compensation. The optical pulses from a mode-locking laser are spectrally broadened by the SPM in the highly nonlinear fiber. A wideband optical frequency comb with 365 spectral lines within 10-dB power variation from the highest spectral power is obtained. By applying a cubic phase modulation via a waveshaper, the effect of TOD which broadens the MPF passband is eliminated. The final implemented MPF has a Q-value as high as 296 and a tuning range of 700 MHz. 相似文献