电子束泵浦KrF激光MOPA系统的同步控制

 介绍研究出的MOPA系统完整的同步控制时间关联逻辑、各单元启动方式及同步系统的硬件。由Fe-Nb-Cu超微晶薄膜材料做成的同轴单匝磁开关及脉冲变压器产生大约150kV、上升时间小于200ns的高压,触发MOPA系统中的Marx发生器,当火花隙欠压比为90％时,Marx发生器中电压建立的时间抖动分别小于13ns和23ns。采用激光触发主开关时,泵浦功率系统总体抖动时间小于10ns,保证了整个电子束泵浦KrF激光MOPA系统的正常运行。     

Soliton-like pulse timing jitter in dispersion-managed systems

In this paper, the timing jitter in dispersion-managed soliton-like systems with the Gaussian pulse is studied by using two methods. Firstly, the derivation of the dynamic equations for the evolution of soliton-like parameters and the timing jitter expressions for the dispersion-managed soliton-like systems are carried out by the perturbed variational method. By analysing and simulating these timing jitter expressions, one can find that the timing jitter is induced by the amplified spontaneous emission noise and the frequency shift, etc. Nonlinear gain can suppress the timing jitter. The chirp sign and the filters action have also effects on the total timing jitter. Secondly, the timing jitter is calculated and analysed by using the moment method. The results of the two methods prove to be consistent with each other.     

Galerkin technique based on beam functions in application to the parametric instability of thermal convection in a vertical slot

A Fourier–Galerkin spectral technique for solving coupled higher‐order initial‐boundary value problems is developed. Conjugated systems arising in thermoconvection that involve both equations of fourth and second spatial orders are considered. The set of so‐called beam functions is used as basis together with the harmonic functions. The necessary formulas for expressing each basis system into series with respect to the other are derived. The convergence rate of the spectral solution series is thoroughly investigated and shown to be fifth‐order algebraic for both linear and nonlinear problems. Though algebraic, the fifth‐order rate of convergence is fully adequate for the generic problems under consideration, which makes the new technique a useful tool in numerical approaches to convective problems. An algorithm is created for the implementation of the method and the results are thoroughly tested and verified on different model examples. The spatial and temporal approximation of the scheme is tested. To further validate the scheme, a singular asymptotic expansion is derived for small values of the modulation frequency and amplitude and the numerical and analytic results are found to be in good agreement. The new technique is applied to the G‐jitter flow, and the Floquet stability diagrams are produced. We obtain the expected alternating isochronous and subharmonic branches and find that stable motions are always isochronous while unstable motions can be either isochronous or subharmonic. The numerical investigation also leads to novel conclusions regarding the dependence of the amplitude of the solutions on some of the governing parameters. Copyright © 2008 John Wiley & Sons, Ltd.     

飞秒锁模固态激光器中放大的自发辐射导致的时基抖动

基于飞秒锁模固态激光系统,推导了激光脉冲的振幅、脉宽的倒数、啁啾、频率、中心位置和位相的运动方程.在低的白噪声的假设下,估算了含啁啾的钛宝石激光器中由放大的自发辐射引起的时基抖动.结果表明:对于一台脉冲轮廓为sech²(1763t/τ)的确定的锁模固态激光系统,时基抖动近似为净群速延迟色散(GDD)的线性函数,且随着GDD的增加而变大;然而,即便在GDD被完全补偿的情况下,时基抖动也不会是零 关键词： 时基抖时 放大的自发辐射 飞秒锁模固态激光系统     

多路激光装置同步技术研究

 多路激光装置同步系统包括精密同步机和数字同步机两种单元技术,它们具有四路延时脉冲（A、B、C、D）和一路标准时钟脉冲（T₀）输出,精密同步机延时同步精度为10ps, 最大触发晃动小于10ps,延时范围200ns;数字同步机：延时同步精度为5ps, 最大触发晃动小于200ps,延时范围10ms。     

傅里叶望远镜大气湍流模拟实验

傅里叶望远术是一种能对深空暗弱目标进行高分辨率成像的技术.为了验证大气湍流对傅里叶望远镜系统的影响,进行了实验室环境下大气湍流模拟实验研究.在三束光傅里叶望远镜实验系统上,通过控制射频驱动器的输出功率来模拟光强抖动,改变射频驱动器的瞬时频率来模拟相位抖动.给出了实验理论依据,推导了湍流强度与实验变量的关系.实验在弱湍流闪烁和相位抖动两种情况下,分别给单束光和三束光加随机扰动并计算其Strehl比.结果表明,只在单束光上加扰动时重建图像影响不大;在三束光上加扰动时,弱湍流光强抖动对傅里叶望远镜系统的成像效果影响具有较大的随机性,而相位抖动会严重影响系统成像质量.因此,消除光强抖动和相位抖动影响是图像重建算法改进应该考虑的一个关键因素.     

强激光大气传输的远场光束亮度仿真研究

为了分析组束激光的战术应用前景,对强激光大气传输的远场光束亮度进行了理论分析和数值模拟。结果表明:10kW量级的强激光有效作用距离不超过10km,需要对发射系统孔径和光束质量进行严格的控制;激光器承载平台的抖动幅度是影响远场光束功率密度的主要因素,在抖动幅度很小或者可以忽略的条件下,湍流和热晕对远场光束起着近乎相同的作用。     

两台联动转镜式高速相机像漂移分析

 讨论了两台联动转镜式高速相机像漂移的各种原因,从理论和实验对相机像漂移的影响因素进行了分析,比如磁电式传感器、材料、制作工艺、装配精度及操作不当等。并针对这些影响因素,提出了解决像漂移的技术措施,通过实验证明了改进效果。     

Novel Strategy for Numerically Evaluating Dark-Soliton Jitter in Optical Communications

In this paper, a novel strategy for numerically evaluating the dark-soliton jitter in optical communications is proposed. It is further tested to be consistent with the famous threshold-value-oriented method for rather larger distances. Then our method is used to calculate the dark-soliton jitter within arbitrary small distances. An excellent agreement is obtained with the theoretical predictions based on the nonlinear Schrödinger equation. Our method is also applicable to some more complicated systems such as the dissipative-dispersive system.     

Jitter Characterization in Optical Preamplifier Direct Detection System

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