三维形状测量方法及发展趋势

随着科学技术和工业生产的迅猛发展,许多领域越来越多地提出了对三给工件尺寸和形状参数测量的要求。在广泛调研的基础上,系统地介绍了目前三维形状测量的主要测量方法,对每种方法在基本原理与主要优缺点及精度进行了分析,阐述了它们的发展现状及应用范围,并对需要干涉研究和发展的领域进行了探讨。     

Gain characteristics of a dual-pump fiber optical parametric amplifier with Raman effect

We investigate the pump-depleted model of a dual-pump fiber optical parametric amplifier(FOPA) with Raman effect.As bandwidth increases,the gain profile of the distorted FOPA would be impacted seriously.Under the widebands,especially when the pump separation is large,zero dispersion wavelength(ZDW) fluctuation is another factor which can not be neglected.Numerical simulations with these comprehensive factors are mainly analyzed to obtain their influence on gain characteristics.Saturated gain spectrum is also discussed in detail.     

基于光纤光栅的编解码器的研究

介绍了基于光纤光栅的光码分多址编解码方法,重点研究了基于均匀光纤光栅、啁啾光纤光栅、超结构光纤光栅编解码器的构造方法,总结了其最新发展动态,指出其应用于光码分多址系统的优缺点.     

一种裸眼3D显示中的多视点校正方案

在裸眼3D显示中,传统的多视点采集方式为均匀采集.研究表明,因柱透镜光栅存在畸变,所以显示器构建的视点分布并不均匀,进而导致显示器视点和采集视点不匹配,产生了视点图像错位、透视关系错误等问题,影响最终的观看体验.针对上述问题,本文提出了一种多视点图像分布校正方案,该方案由一种视点筛选算法和中间视点生成网络构成:结合空间...     

高非线性光纤中光子对产生中的噪声及其抑制

在高非线性光纤中产生高质量的光子对对于量子信息的应用具有重要意义.在分析基于光纤中四波混频效应产生光子对原理的基础上,指出了影响光子对产生噪声的主要因素.讨论了抑制噪声的几种可能的方法,采用冷却光纤、短脉冲泵浦光源和狭窄的滤波宽度和增大四波混频的信号和闲频光带宽等方法可以有效地降低噪声,从而为高效产生光子对提供了依据.     

HNL-PCF中的SSFS及其在光纤通信中的应用

分析了高非线性光子晶体光纤(HNL-PCF)中拉曼孤子自频移(SSFS)的原理.讨论了HNL-PCF中SSFS效应在波长变换、飞秒孤子脉冲、超快数模转换和改善通信的稳定性等方面的应用.随着PCF技术的发展和对SSFS研究的深入,基于PCF中SSFS的各种器件将在未来的光纤通信系统中发挥重要的作用.     

基于光纤布拉格光栅的化学传感器

除掉光纤布拉格光栅的包层,可以使它的布拉格波长对外界环境的折射率变化敏感。采用氢氟酸腐蚀掉光纤布拉格光栅的包层,获得了直径约为6 μm的布拉格光栅。实验研究了布拉格波长对化学溶液的浓度敏感性特征,结果表明:采用10 pm分辨率的光谱仪,丙二醇溶液在低浓度时的浓度分辨率为0.7%,在高浓度时的分辨率为0.32%;糖溶液在低浓度时的分辨率为0.55%,高浓度时为0.1%。采用商用的分辨率为1 pm的高精度波长解调系统,它们的分辨率可以提高一个数量级。     

基于高非线性PCF中SSFS效应的波长变换技术研究

理论分析了光子晶体光纤中孤子自频移(Soliton Self-Frequency Shift,SSFS)这一光纤的非线性效应,研究了利用SSFS实现波长变换的薛定谔方程求解问题,讨论了输入功率、PCF的长度、非线性系数等参数对波长变换范围及转换效率的影响,指出输入功率与PCF的长度相对于波长变换的输出中心波长从几纳米到几十纳米基本呈线性变化,当使用较长的PCF时,光纤中的高阶孤子和孤子分裂效应将限制波长变换的效率.基于高非线性PCF的SSFS波长变换是一种简单可行且高效的方案.     

A flexible receiver with fiber optical parametric amplifier in OCDMA-FSO communication system

A new receiver is proposed, which uses the fiber optical parametric amplifier（FOPA） in optical code division multiple access（OCDMA） over free space optic（FSO） communication system. The noise tolerance as the performance index in this receiver is derived. The receiver can not only improve the noise tolerance but also change the pump data conveniently for adapting to the length variation of the coding sequence under a complex and fast-changing weather condition. The influence of different factors on the noise tolerance is analyzed, and a significant improvement of about 18.77 d B for the noise tolerance can be achieved when the pump power and the length of coding sequence are 5 W and 256, respectively.     

Influence of Raman effect on the noise characteristics in a dual pump FOPA

Influence induced by Raman effect on the noise characteristics of a depleted and lossy dual pump fiber optical parametric amplifier (FOPA) is investigated. Taking the Raman effect into account, the modified coupled amplitude equations are firstly built, then the influences of Raman effect on the stokes and anti-stokes wavelengths with different initial signal powers are further analyzed. Besides, the effect on the FOPA gain is also shown with the same initial signal power and constant noise figure (NF).