Beam Waveguide Reflector with Integrated Direction-Finding Antenna for In-Situ Alignment

An in-situ alignment system for beam waveguides based on an interferometric direction-finding antenna was investigated numerically and experimentally. The system consists of a reflector with four off-central positioned waveguide couplers in two directions. By nulling the difference of the power signals as well as the mixing signal from each coupler pair, spatial and angular alignments of a beam impinging on the mirror can be performed.In this paper, the characteristics of such a mirror are presented, and the design of a prototype intended for use in an ECH transmission line at LHD is described. Low-power as well as high-power tests at a frequency of 82.7 GHz were carried out, and the results are discussed. The device shows a high performance in agreement with theory.     

光学定向散射膜片

论述一种简单的光学定向散射方法和用此方法做成的光学定向散射膜片，并给出此种膜片的制作试验结果。     

一维势阱中被噪声驱动的粒子的逃逸问题

通过计算机数值模拟直接解朗之万方程，得到一维势阱中被高斯白噪声驱动的粒子的逃逸率，并与理论结果进行了对照。     

蚀刻表面面形的分析

采用一个有效的数学模型,分析了在蚀刻工艺中基底自身面形轮廓的曲线形状对基底局部区域的蚀刻速率产生的影响,并通过对数学模型的理论分析和计算机模拟得出受此影响而产生的面形形状,并将结果与实验进行对比.利用这个数学模型对使用离子束蚀刻制作单台阶光栅的台阶与沟槽部分的表面面形随时间的演变过程进行了计算机模拟分析,并通过把理论结果与在实验中得到的蚀刻表面在原子力显微镜(AFM)下拍摄的照片进行比较,结果说明这种模拟分析能够保证对该问题分析所要求的精度,从而也证明了理论模型的合理性和正确性.     

Effect of Quantum Well Width Reduction for GaInNAs/GaAs Lasers

We investigated the function of the quantum well (QW) width for laser characteristics especially for reduction of the well width. We pointed out that such reduction has almost no influence on the optical gain or the carrier overflow for a large conduction band offset system, such as GaInNAs QWs. A thin QW is advantageous for suppression of the carrier overflow to the higher quantized energy levels which results in good temperature and gain characteristics. Thin GaInNAs QWs is a good candidate for an active layer structure of the lasers utilized in the next optical communication systems.     

Spontaneous emission coupling factors in planar micro-cavity lasers with distributed Bragg reflectors

In this article, a considerable value of spontaneous emission factor is estimated based on the spontaneous emission radiation patterns in micro-cavity lasers. After the spontaneous emission for a dipole in the micro-cavity is studied, the confinements of vacuum fields and electrons are considered together for a quantum well in the micro-cavity laser. The TE mode and TM mode spontaneous emission spectra are presented for a single quantum well embedded in a planar micro-cavity laser at 300 K. The results show that the TE mode spontaneous emission spectrum is enhanced, whereas the TM mode spontaneous emission is suppressed greatly. The maximum values obtained for the spontaneous emission coupling factors are 0.2 and 0.0055 for a dipole and a quantum well planar micro-cavity laser with distributed Bragg reflectors, respectively.     

Deformation and Filtration Near a Well in a Porous Stratum with Linear Memory

The linearized equations for saturated elastic porous media and for surrounding elastic rock are solved simultaneously; and the Volterra principle is used to derive an integro-differential filtration equation for a homogeneous weakly compressible fluid in an axisymmetric stratum with linear memory and central well. An analytical expression for porosity variation is obtained and then used to determine the permeability coefficient. The solutions are analyzed for the case where the stratum exhibits memory described by regular and singular kernels of the integral operator     

压电调制反射光谱研究GaAs/Al0.29Ga0.71As单量子阱

报道了压电调制反射测量系统的建立，应用该系统获得了势阱宽度分别为5nm和25nm的两个G aAs/Al_0.29Ga_0.71As单量子阱的压电调制反射谱. 从图谱中可以看 出，在室 温下能够较容易地分辨出和轻、重空穴相关联的子带跃迁. 在阱宽25nm的样品中还观察到了 自旋-轨道跃迁. 利用有效质量理论近似计算，对量子阱样品的图谱结构进行了指认，发现 实验值和计算值能够较好地符合. 关键词： 压电调制反射光谱 单量子阱 分子束外延     

光脉冲在半导体中非线性传输特性的时域和频域分析

本文从理论上研究了半导体非共振透明区光脉冲非线性传输的时域和频域行为,并对应用自由载流子非线性折射效应来构造非线性方向耦合器的可能性进行了分析。     

Monte Carlo simulation of overdamped motion in a double well potential under the influence of coloured noise

We present a Monte Carlo simulation algorithm for evaluating the stationary probability and the mean and the variance of first passage times in any dynamical system under the influence of additive coloured Gaussian and Marcovian noise (Ornstein-Uhlenbeck process). Our algorithm generates the Ornstein-Uhlenbeck process by a superposition of a finite number of random telegraph processes. We obtain our results from a direct evaluation of the trajectories. We apply our method to the overdamped motion of a particle in a double well potential. We compare our simulation results with various analytic approximations for the stationary probability and the mean first passage times.