共查询到20条相似文献,搜索用时 187 毫秒
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王润轩 《光电子技术与信息》2003,16(4):13-15
在分析单模光纤群速度色朦胧(GVD)效应和自相位调制(SPM)效应相互作用的基础上,导出GVD和SPM共同作用引起的啁啾表达式,全面分析了色散长度LD、非线性长度LNL与啁啾变化的关系。结果表明:随着LD/LNL的不同,啁啾特性有着显著变化,当N=LD/LNL=1,即实现了单模光纤中群速度色散效应与非线性效应相互作用所致啁啾的最佳匹配,通过控制脉冲输入功率,可望实现高斯光脉冲无啁啾的稳定传输。 相似文献
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光纤GVD和SPM效应所致频率啁啾的匹配 总被引:1,自引:0,他引:1
在分析单模光纤群速度色散(GVD)效应和自相位调制(SPM)效应相互作用的基础上,推导出GVD和SPM共同作用引起的啁啾表达式;全面分析了色散长度LD、非线性长度LNL与啁啾变化的关系。结果表明,随着LD/LNI的不同,啁啾特性有着显著变化;当N=LD/LNL=1,即实现了单模光线纤中群速度色散效应与非线性效应相互作用所致啁啾的最佳匹配;通过控制脉冲输入功率,可望实现光脉冲无啁啾的稳定传输。 相似文献
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激光腔内的色散补偿问题是获得窄脉冲的关键,所以色散补偿元件的选择非常重要.传统的色散补偿元件棱镜对可以对二阶色散(群延迟色散)进行较好的补偿,但对高阶色散的补偿却无能为力.本文介绍了色散补偿元件啁啾镜的基本原理和优化设计思想,阐述了优化设计的基本过程,并根据激光腔内增益介质的实际色散情况,通过计算机模拟进行了相应啁啾镜设计的优化计算,以期保证啁啾镜在更宽的波段范围内能够获得相对较为稳定的色散补偿,尤其是对高阶色散的补偿.通过优化计算结果具体分析了影响啁啾镜色散补偿特性的几个重要因素,如色散量、色散带宽、膜层数以及单一膜层的厚度变化等对啁啾镜光学特性造成的影响都比较大.其中色散量的控制和色散带宽的选择是其中最重要的优化设计指标.(OB22) 相似文献
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王润轩 《大气与环境光学学报》2003,(4)
在分析单模光纤群速度色散(GVD)效应和自相位调制(SPM)效应相互作用的基础上,导出GVD和SPM共同作用引起的啁啾表达式,全面分析了色散长度L_D、非线性长度L_(NL)与啁啾变化的关系。结果表明:随着L_D/L_(NL)的不同,啁啾特性有着显著变化,当N=L_D/L_(NL)=1,即实现了单模光纤中群速度色散效应与非线性效应相互作用所致啁啾的最佳匹配,通过控制脉冲输入功率,可望实现高斯光脉冲无啁啾的稳定传输。 相似文献
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对存在偏振模色散(PMD)和群时延(GD)抖动的非理想线性啁啾光纤光栅的色散补偿特性进行了研究。实验测量了啁啾光纤光栅的群时延谱和偏振模色散光谱,理论分析和实验测量表明,啁啾光纤光栅差分群时延(DGD)抖动与其时延抖动密切相关。通过数值模拟方法,计算了线性啁啾光纤光栅偏振模色散眼图代价与入射到啁啾光纤光栅色散补偿器的光信号的偏振方向的关系,计算结果表明在使用啁啾光纤光栅色散补偿器时应对光信号的偏振方向进行调整,以获得最佳补偿效果。另外结合实验数据,模拟计算并讨论了非理想线性啁啾光纤光栅群时延抖动和偏振模色散引起的信号的展宽和脉冲形状的劣化。 相似文献
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脉冲初始啁啾对色散管理孤子传输性能的影响 总被引:6,自引:2,他引:4
本文数值分析了脉冲始啁啾对色散控制孤子传输性的影响,得出的结论为:适当地选择正的初始啁啾可以提高后补偿系统中孤子的传输特性;负啁啾可以提高前补偿系统中孤子的传输性能。初始啁啾参量的大小与色散补偿的结构以及平均输入功率有关,并提出对采用啁啾技术的色散管理孤子系统设计的新方法。 相似文献
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无初始啁啾高斯光脉冲的色散展宽及色散补偿 总被引:9,自引:1,他引:8
对无初始啁啾高斯脉冲在普通单模光纤中的传输特性及线性啁啾光纤光栅的色散补偿特性进行了理论分析和数值模拟。结果表明,光纤的色散导致了传输脉冲的展宽,线性啁啾光纤光栅能够实现对展宽脉冲的良好补偿,啁啾光栅时延曲线的平滑度和线性度都是影响其色散补偿性能的重要因素。本文对啁啾光纤光栅的制作及其在色散补偿中的应用有一定的指导意义。 相似文献
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A pulse-compression phenomenon of a chirp pulse transmitted through a long single-mode fibre is presented. The chirp pulse is obtained by using a carrier density change in a DFB laser diode. The pulse width is 1.7 ns at the single-mode-fibre input and is compressed to 0.35 ns after a 104 km transmission at 1.54 ?m wavelength. 相似文献
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正常色散光纤消啁啾的孤子传输实验 总被引:1,自引:0,他引:1
利用正常色散光纤消啁啾成功地进行了1Gbit/s,23km的光孤子传输,观察到了一阶和高阶孤子传输现象。在对光脉冲消啁啾过程中发现了一个新的现象:适当长度的正常色散光纤消啁啾不仅能够压窄负啁啾的脉宽,而且能够压窄频谱。 相似文献
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初始啁啾和光纤损耗对皮秒脉冲孤子效应压缩的影响 总被引:2,自引:0,他引:2
运用分步傅立叶方法数值模拟了皮秒脉冲在单模光纤中的传输 ,计算和分析了初始啁啾和光纤损耗对皮秒脉冲孤子效应压缩的影响。结果表明 ,两者对具有一定峰值功率的脉冲孤子效应压缩的影响具有互补性 ,即两者对脉冲压缩的作用相反。进一步研究表明 ,对在损耗光纤中传输的皮秒脉冲 ,如果给其加适当大小的初始啁啾将得到很好的压缩效果 相似文献
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S.O. Yakushev O.V. Shulika S.I. Petrov I.A. Sukhoivanov 《Microelectronics Journal》2008,39(3-4):690-695
Chirped mirrors are widely used in ultrafast optics as broadband devices for dispersion compensation. Time domain analysis in contrast to frequency domain one allows the direct investigation of pulse profile changing during chirp compression. We model the chirped pulse compression with single chirped mirror and assembly of similar mirrors. Our analysis shows there is similar effect of chirp compensation in both cases. However, injurious group delay oscillations in the single mirror strongly decrease pulse quality in assembly of mirrors and can even damage pulse waveform. Angle of incidence and polarization also play crucial role and should be taken into account. 相似文献
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Chirp and stability of mode-locked semiconductor lasers 总被引:1,自引:0,他引:1
A numerical study of mode-locked semiconductor lasers is presented with special attention to the chirp characteristics and to dispersion-related criteria for stable pulse-train emission. The dependence of the pulse chirp upon the refractive-index change, both with carrier density and carrier temperature changes, is discussed. The experimental observation of blue-chirped pulses for passive mode-locking in contrast to red-chirped pulses for active mode-locking is found to be due to the different contributions of gain and absorber media to the refractive-index change. In addition, it is revealed that the boundary of the stable operation regime is critically influenced by the spectral characteristics of laser and external cavity. Design considerations toward the achievement of high pulse energy, narrow spectral bandwidth, and linear chirp are given 相似文献
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Vibro-acoustography (VA) is an imaging technique that uses the dynamic (oscillatory) radiation force of two continuous-wave (CW) ultrasound to image objects at low frequency (within the kHz range). In this technique, the dynamic radiation force is created by means of a confocused transducer emitting two ultrasound beams at slightly-shifted frequencies f1 and f2 = f1 + deltaf. It has been demonstrated previously that high-resolution images of various types of inclusions and tissues can be obtained using this technique. However, if the targeted object reflects ultrasound directly back to the transducer, standing waves are produced that result in an artifact in the VA image. The goal of this study is to remove the standing wave artifact and improve VA images by means of a new process called chirp imaging. The procedure consists of sweeping the frequencies of the primary ultrasound beams in a selected bandwidth while keeping deltaf constant during the sweep. The chirp image is produced by averaging the amplitude of the acoustic emission produced during the sweep. Vibro-acoustography chirp imaging experiments are performed on a stainless-steel sphere attached to a latex sheet in a tank of degassed water. The resulting chirp images demonstrate remarkable reduction of the standing wave artifact compared to the "fixed frequency" VA images. 相似文献