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1.
皮秒光脉冲在光纤中的传播特性测量   总被引:1,自引:0,他引:1  
刘天夫  胡桂林 《物理》2002,31(5):310-312
文章讨论了皮秒激光脉冲在单模光纤传输中光纤介质的色散及非线性折射率等效应对皮秒光信号的影响,利用时间相关单光子计数系统,观测了皮秒激光脉冲在单模光纤中的展宽及皮秒自聚焦现象,并对光纤中皮秒光脉冲的畸变进行了检测与研究。  相似文献   

2.
脉冲γ射线对光纤的辐射效应   总被引:1,自引:0,他引:1       下载免费PDF全文
介绍了光纤的损耗机制和γ射线对光纤的辐射效应,设计了针对脉冲γ射线作用于光纤而产生辐射感生损耗的实验测量系统。利用平均光子能量为0.3 MeV、脉冲宽度25 ns、剂量率2.03×107Gy.s-1,和平均光子能量为1.0 MeV、脉冲宽度25 ns、剂量率5.32×109Gy.s-1的2种脉冲γ射线分别作用于多模和单模光纤,分别采用波长为405,660,850,1 310和1 550 nm的激光光纤传输系统对辐射感生损耗进行了测量。获得了光纤辐射感生损耗和辐射剂量的关系,并对实验结果进行分析。从实验结果可以看出:在近红外到可见光范围内,脉冲γ射线对光纤作用产生的辐射感生损耗随探测波长减小而增大;在0.1~3.5 Gy剂量范围内,多模光纤辐射感生损耗和辐射剂量呈线性关系。分析辐射对光纤的作用机制和实验结果后得出:光纤基质原子的电子能级对传输光子的共振吸收而造成吸收损耗增加;光纤折射率分布的改变从而导致波导损耗增加。  相似文献   

3.
多模梯度纤维中由于折射率剖面的畸变及色散的影响,可将其看成截止频率为f_0的低通滤波器。在时域上表现为激光脉冲经过其一段距离的传输后脉冲变宽,幅度降低。我们采用时域法测量其频带宽度。应用PS量级激光脉冲和具有微机准实时图象数据处理系统的变象管扫描相机系统测量激光脉冲和宽度(半高宽)τ_1和激光脉冲经千米光纤传输后的脉冲宽度τ_2将激光波形近似认为是高斯分布,则可以如下换算光纤带宽B:  相似文献   

4.
采用双并行马赫曾德尔调制器产生高斯脉冲一阶微分和二阶微分型超宽带脉冲雷达信号和光载无线电传输技术,通过仿真研究了两种超宽带脉冲雷达信号在标准单模光纤中的传输特性.结果表明,高斯脉冲一阶微分型脉冲随着传输距离的增大而不断展宽,而高斯脉冲二阶微分型脉冲则先压缩后展宽.经100km标准单模光纤传输之后,在传输终端采用色散补偿光纤对传输信号进行不同程度的色散补偿,可获得满足美国联邦通信委员会规范要求的不同宽度高斯脉冲一阶微分和二阶微分型脉冲信号.  相似文献   

5.
光载超宽带脉冲雷达信号传输性能研究   总被引:2,自引:1,他引:1  
姚现勋  闫娟娟 《光子学报》2012,41(5):522-527
采用双并行马赫曾德尔调制器产生高斯脉冲一阶微分和二阶微分型超宽带脉冲雷达信号和光载无线电传输技术,通过仿真研究了两种超宽带脉冲雷达信号在标准单模光纤中的传输特性.结果表明,高斯脉冲一阶微分型脉冲随着传输距离的增大而不断展宽,而高斯脉冲二阶微分型脉冲则先压缩后展宽.经100km标准单模光纤传输之后,在传输终端采用色散补偿光纤对传输信号进行不同程度的色散补偿,可获得满足美国联邦通信委员会规范要求的不同宽度高斯脉冲一阶微分和二阶微分型脉冲信号.  相似文献   

6.
光纤取样可以降低高功率激光脉冲时间波形测量成本,并提高测量系统抗干扰能力。光纤耦合效率、信号保真度、信号获取率是采用光纤取样测量高功率激光脉冲时间波形的难点。针对大型高功率激光脉冲宽度窄、光束口径大以及输出光束远场漂移量大等特点,设计了一套激光脉冲光纤取样系统,在全口径取样和不降低信号保真度的条件下有效解决了测量系统信号获取率低下的问题,充分保证了测量系统的可靠性。  相似文献   

7.
周晓军  张旨遥  隋展  王建军 《光学学报》2008,28(s1):159-163
通过数值求解广义非线性薛定谔方程,分析了32路线性啁啾高斯脉冲堆积后的整形脉冲在单模光纤中的传输特性。结果表明经50 m单模光纤传输后脉冲的脉宽和包络形状基本不变; 非线性效应中的自相位调制和脉冲内Raman散射对脉冲频域特性影响较大,使频谱展宽约40 THz,中心角频率下移约10 THz; 而自陡效应,三阶色散对传输特性影响不大。  相似文献   

8.
基于高功率激光系统前端全光纤脉冲整形系统输出的脉冲特性,以两路脉冲堆积为例,理论分析并讨论了光纤中群速度色散的作用,提出了分离距离的概念,得出了整形脉冲时间调制周期、瞬时频率,以及初始啁啾对脉冲波形影响的解析结果。数值模拟了脉冲波形、瞬时频率在正、负色散光纤中随时间的变化特性,以及时间调制周期与传输距离之间的关系。结果表明,堆积脉冲不同位置瞬时频率变化不同;脉冲时间调制周期与时延和初始啁啾以及色散符号有关。  相似文献   

9.
孙军强  黄德修 《物理学报》1996,45(6):960-965
提出一种结构新颖且简单的环形掺饵光纤激光器,在较低的抽运参数条件下观察到了自持脉冲。就抽运参数、光纤环中单模光纤长度对输出激光脉冲特性的影响等进行了实验研究。结果表明,通过合适地调节激光器的有关参数可以实现对输出激光脉冲特性的控制。  相似文献   

10.
报道一种全固化、全光纤的用于高功率激光驱动的惯性约束聚变驱动器的光脉冲产生系统,采用单纵模振荡器输出连续激光信号,经过相位调制器和振幅调制器,得到一个时间波形上已整形且具有一定带宽(约0.1 nm)的激光脉冲,经光纤放大器放大并经光纤分束器分束后同时输出四路激光脉冲,各路激光脉冲先通过时间同步调整单元精确控制时间同步关系后,经可编程光纤衰减器调节各路之间的功率平衡后再通过光纤放大器做进一步放大并通过150 m光纤传输输出至预放系统.该光纤系统可输出0.3—20 ns、带宽0.1 nm、能量数纳焦的几乎任意 关键词: 激光聚变驱动器 前端 光纤激光系统  相似文献   

11.
The phenomenon of temporal pulse dispersion, which is a key characteristic of an optical fiber communication system is described from the first principles. Beginning with the basics of dispersion in a bulk medium, these concepts are then applied to propagation of a pulse in an optical fiber. Details of modeling dispersion are then described in the context of dispersion tailoring and dispersion compensation with a view to form the foundation for subsequent chapters on dispersion compensation that follow in this report. Basic physics behind the design target for dispersion compensating fibers is discussed, which should be useful to fiber designers.  相似文献   

12.
We propose a three-dimensional (3D) finite-difference time-domain (FDTD) method to analyze the pulse propagation characteristics in microstructured optical fibers (MOFs). The computation domain size is greatly reduced by adopting the technique of moving problem space. The propagating pulse is virtually held in the buffer cell of the problem space as simulation continues. This method is capable to investigate the temporal evolution of the propagating pulse. Spectral information can be obtained by Fourier analysis. As an example, the influence of the kerr nonlinearity on the optical pulse propagation in a Lorentz dispersive MOF is demonstrated. The model is also used to simulate the nonlinear interactions between the pump spectral broadening and third harmonic generations in a highly nonlinear fused silica nanowire with good agreement with the generalized nonlinear envelop equation (GNEE) model.  相似文献   

13.
Peacock AC 《Optics letters》2010,35(21):3697-3699
Numerical simulations are used to investigate soliton-like propagation in tapered silicon core optical fibers. The simulations are based on a realistic tapered structure with nanoscale core dimensions and a decreasing anomalous dispersion profile to compensate for the effects of linear and nonlinear loss. An intensity misfit parameter is used to establish the optimum taper dimensions that preserve the pulse shape while reducing temporal broadening. Soliton formation from Gaussian input pulses is also observed--further evidence of the potential for tapered silicon fibers to find use in a range of signal processing applications.  相似文献   

14.
The characterization of medium- to low-energy shaped pulses at 1.55 7m through frequency-resolved optical gating (FROG) is illustrated. This capability enables the study of ultrafast pulse propagation through optical fibers. The phase dynamics detected furnishes insight on pulse evolution, specifically on soliton formation - a subject of great importance for telecommunication applications. The combination of shaping and propagation of ultrafast pulses in fibers is examined theoretically using an adaptive pulse-shaping model, based on genetic algorithms, that furnishes optimized pulse shapes for fiber propagation.  相似文献   

15.
类明孤子在光纤中传输特性的变分研究   总被引:10,自引:4,他引:6  
谢应茂 《光学学报》2004,24(4):52-455
应用变分法,研究了微扰对类明孤子在光纤巾非线性传输特性的影响,导出了类明孤子脉冲参量演化的动力学方程。它统一了在单模光纤、色散缓变光纤或色散控制光纤中类明孤子脉冲参量演化的动力学方程。在此基础上,计算了色散缓变光纤中的线性高阶色散微扰。结果表明:线性高阶色散对类明孤子脉冲的位置和相位有影响,而对振幅、宽度和啁啾没有影响;光纤色散缓变对类明孤子脉冲的所有参量均有影响。  相似文献   

16.
王存莲  赵春  姜凯  肖燕 《物理实验》2007,27(6):14-17
从描述超短光脉冲在光纤中传输的高阶非线性薛定谔方程入手,使用傅里叶变换的分裂算符法,通过计算机模拟,研究了超高斯光脉冲在色散管理光纤系统中的传输特性,并考察了超高斯光脉冲在加入随机噪声后传输的稳定性以及脉冲间的相互作用.  相似文献   

17.
A useful analysis of contra-propagating optical pulses in semiconductor optical amplifier (SOA) is presented. Pulse temporal and spectral evolutions are investigated by resolving coupled equations describing pulse field propagation and SOA gain dynamics. With reference to the case of single pulse propagation, collision between pulses tends to maintain a good time-bandwidth product of amplified pulse and could provide a temporal compression by about 10% compared to pulse’s initial width.  相似文献   

18.
The nonreciprocity of the dynamics of Gaussian optical pulses propagating in inhomogeneous nonlinear active optical fibers with nonlinearity dispersion is considered. A substantial nonreciprocity of the time of pulse propagation along the optical fiber in the forward and backward directions is revealed. The possibility of realizing the regime of superluminal propagation of a pulse in one of the directions of the optical fiber is indicated.  相似文献   

19.
Chirped cladding is proposed as a novel tailoring tool to simultaneously attain wider transmission window and reduced temporal dispersion in an all-solid Bragg-like microstructured optical fiber as compared to its perfectly periodic cladding counterpart. This design route for photonic bandgap microstructured fibers could be exploited as an additional degree of freedom for bandgap engineering. A suitably chirped clad fiber could be gainfully exploited to deliver femto-second pulse with ultra wide bandwidth. Further, generation of self-similar parabolic profile pulse is demonstrated by simulating propagation of an input Gaussian pulse through a 2 m long sample of such a linearly tapered Bragg like fiber.  相似文献   

20.
郑宏军  刘山亮 《中国物理》2006,15(8):1831-1837
In this paper, the linear propagation characteristics of the exponential optical pulse with initial linear and nonlinear frequency chirp are numerically studied in a single mode fibre for β2 〈 0. It can be found that the temporal full width at half maximum and time-bandwidth product of exponential pulse monotonically increase with the increase of propagation distance and decrease with the increase of linear chirp C for C 〈 0.5, go through an initial decreasing stage near ζ= 1, then increase with the increase of propagation distance and linear chirp C for C 〉 0.5. The broadening of pulses with negative chirp is faster than that with positive chirp. The exponential pulse with linear chirp gradually evolves into a near-Gaussian pulse. The effect of nonlinear chirp on waveform of the pulse is much greater than that of linear chirp. The temporal waveform breaking of exponential pulse with nonlinear chirp is first observed in linear propagation. Furthermore, the expressions of the spectral width and time-bandwidth product of the exponential optical pulse with the frequency chirp are given by use of the numerical analysis method.  相似文献   

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