Determination of GR-IN optical fibre parameters from transverse interferograms considering the refraction of the incident ray by the fibre

The core–cladding refractive index difference Δn and the index gradient profile parameter of the graded index (GR-IN) optical fibre has been determined. The curve representing the real path, in the core region, due to refraction of the beam and the change in the exit wavefront are considered. Multiple-beam Fizeau fringes and two-beam interference Pluta polarizing microscope, are used for this investigation. A new method, based on a derived mathematical expression, is used with a prepared computer program to estimate the fringe shift inside GR-IN of the fibre core. The estimated and experimental values of the fringe shift, along the core radius, are used to obtain the refractive index profile of the optical fibre. A comparison between the new method and a previous model considering the refraction has been shown. Microinterferograms are given for illustrations.     

1×16多模干涉型GaAs光功分器的研制

设计并制作了一种能直接与通信用标准单模光纤阵列相耦合的 1× 16多模干涉型光功分器。其输入、输出单模波导采用离散谱折射率法优化设计 ,获得了脊宽为 3μm、脊高为 2 .9μm和理论传输损耗约为 0 .0 2 8dB cm的单模脊形光波导。分析表明 ,这种深刻蚀多模干涉型光功分器具有较大的制作容差性、较宽的工作带宽以及几乎可忽略的极化依赖性。测试结果表明 ,器件实现了 1× 16光功分器功能     

干涉截面对核子自旋结构函数的影响

利用非相对论和相对论夸克模型分别计算了干涉截面对极化核子自旋结构函数的影响.计算所得到的明显的作用为今后实验上抽取核子自旋结构函数提供了依据.     

高能聚变产物与燃料粒子间的核加库仑相干散射

在具有较高电子温度的D－^3He聚变等离子体中,强子弹性散射、核加库仑相干散射和核反应产物的传播等效尖变得相对重要,而聚变产生的高能离子与电子的库仑相互作用变弱。部分本底燃料离子被聚变产生的高能离子轰击而成为麦克斯韦分布函数尾部的“超热”燃料离子,从而提高了D-^3He聚变反应。     

Reverse-saturated absorption and narrow line in the absorption spectrum of a V-type three-level medium

We study the absorption spectrum of a V-type three-level atom when the laser beam interacts only with one of its two transitions. With the presence of vacuum-induced quantum interference, the absorption spectrum shows some new interesting features, which include ultranarrow absorption line, transparency, and a reverse-saturated absorption that is characterized by a larger absorption with increasing laser intensity.     

Numerical analysis of the smart DROS

A digital superconducting quantum interference device (SQUID) has the potential for a very large dynamic range and a very high slew rate. Our concept of the digital SQUID consists of a double relaxation oscillation SQUID (DROS) with the complete flux locked loop (FLL) electronics on one single chip. The key element of the FLL circuitry is a superconducting up-down counter, which supplies the feedback flux to the DROS. In this paper we will concentrate on the numerical simulations of our new 100 MHz smart DROS. In this new design, the quantization unit of the feedback flux, δΦ_fb=52 mΦ₀, was optimized with respect to the flux noise of the DROS. By doing so, the flux slew rate was maximized without compromising the sensitivity. The optimization resulted in a maximum flux slew rate of δΦ_sig/δt=5×10⁶Φ₀/s.     

杨氏双干涉的光强分布计算

数值计算了杨氏双孔干涉的光强分布,与傍轴近假条件下的结果作了比较,并以图形的方式显示了干涉条纹的形状。     

CCD渗入双棱镜实验--计算机辅助普通物理实验教学的尝试

针对当前普物实验的弊端,以光的干涉实验力例,讲述了将现代科技渗入普物实验后的良好效果：即不削弱学生实验基本技能训练,又极大地提高实验的直观性、方便性;让学征在实验中体到现代科技的影响,提高了学生的实验兴趣。     

相移技术中五步等步长Stoilov算法的性能分析

Stoilov算法是近几年提出的一种五步等步长相移算法。有关文献中的误差分析表明 ,该算法的性能优于四步等步长Carr啨算法闹懈隽耍樱簦铮椋欤铮鏊惴ǖ恼繁泶锸?,采用线性误差理论详细分析了算法的性能 ,尤其是算法性能对相移步长的依赖关系。分析表明 ,可以选择一个最佳的相移步长以有效减少位相测量误差 :相移步长为 5 2°时可有效抑制二次相移量误差的影响 ;相移步长为 90°时可极大地减少光强误差的影响。最后给出了Stoilov算法与Carr啨算法和Hariharan算法的比较。     

8-信道MMI阵列波导光栅复用/解复用器的研制

本文首先详细分析了基于自镜象效应的MMIDMUX器件的基本工作原理,在此基础上,在GaAs/GaAlAs系材料上完成了对8信道MMIDMUX的具体设计.该器件的输入、输出单模波导和SIE多模波导采用离散谱折射率法进行优化设计,最后获得了当输入、输出单模波导宽度为3μm、SIE多模波导宽度和长度分别为40μm和1731.45μm时,该器件对8信道波长的隔离度为～26dB,理论传输损耗为～0.24dB.