HL-2M 装置上汤姆逊散射系统中多色光谱仪的优化设计

设计并优化了一种新型多色仪。该方案中滤光片和探测器更加易于安装,缩短了光程长度,提高了对散射信号的探测本领,减少了透镜的使用数量,提高了多色光谱仪的传输率。通过数值计算,得到在200~20000eV 温度范围内多色光谱仪的通道数为7 是最优化结果。最后,对7 通道多色仪的相关参数进行优化设计,使用模拟退火法计算优化各通道干涉滤光片的波长范围。     

微型宽波段光谱仪光学系统设计

针对国内基于M型Czerny-Turner结构的宽波段微型光谱仪研究较少的情况,对微型宽波段光谱仪进行了设计,并提出了完整的设计流程。根据几何光学原理,分析了光学系统各个参数之间的约束关系,据此设计、计算得到了光学系统的基本参数,并使用Zemax进行仿真。为了提高仪器的紫外响应,在CCD的前端增加了Lumogen镀膜的滤光片。实际制做的光谱仪测量结果表明:光谱仪的分辨率在200 nm~1100 nm全波段范围内达到1.5 nm,中心分辨率达到1 nm,满足设计需求。     

成像光谱偏振仪研究进展

成像光谱偏振仪是一类同时具有成像、光谱测量和偏振测量功能的新型光电传感器.介绍了成像光谱偏振仪的原理,对近些年来国内外成像光谱偏振仪的研究进展进行了总结,对基于声光可调谐滤光片、液晶可调谐滤光片等新器件的成像光谱偏振仪和通过在狭缝色散型、空间调制傅里叶变换型和层析型成像光谱仪的光路中添加偏振器件构成的成像光谱偏振仪的原...     

应用高光谱仪探测叶片反射光谱中的荧光

介绍了一种利用光谱仪进行荧光测量的方法。采用LI 1800_12S积分球,耦合ASD地物光谱仪,在光源前面分别加载长波通、短波通截止滤光片,按照不同算法提取叶片表观反射光谱中的荧光。结果表明利用长波通滤光片测得的表观反射率差值光谱可以代表荧光光谱,在红光区和远红光区表现为明显的双峰特征,不同截止波长滤光片提取的荧光强度不同。采用短波通滤光片可直接获得荧光光谱,不同植物种类荧光光谱差异明显。此法对于植物被动荧光遥感探测及叶绿素荧光仪的研制和开发具有一定参考价值。     

星载超光谱成像仪杂散光及其测量

超光谱成像仪比一般光谱仪器具有更多的光谱通道和更高的光谱分辨率,而杂散光是影响超光谱成像仪光谱测节精度的重要因素之一,当前光谱仪器的杂散光测量方法尚不能满足超光谱成像仪杂散光检测的需要.作者探讨了此类成像光谱仪杂散光的定义、来源和危害,论述了使用杂散光影响因子di,j描述光谱仪杂散光的可行性和优越性,并给出了杂散光受扰系数fi(λ)和杂散光干扰系数Fi(λ)的定义、物理意义和工程应用价值.最后,介绍了使用窄带滤光片测量星载超光谱成像仪杂散光的测量系统组成、测量步骤和测量结果.结果表明:杂散光影响因子di,j能正确表示光谱仪的杂散光特性,与光源、滤光片、探测器等测量条件无关,而测量效率比谱杂散光系数法至少提高1倍,满足星载超光谱成像仪杂散光测量的工程需要.     

红外滤光片低温光谱特性研究

低温光谱是红外滤光片一项重要的考核参数，采用傅里叶光谱仪测试了红外滤光片在安装滤光片架前后的常温和85K低温光谱，同时利用有限元分析方法模拟了85K的红外滤光片安装滤光片支架前后的形变和应力，分析和比较了试验结果，为进一步优化红外滤光片的可靠性设计提供了参考。     

滤光片对瞬态光学高温计通道线性的影响

 滤光片是瞬态光学高温计系统中的一个重要器件,滤光片的技术参数对高温计的性能有重要影响。对窄带滤光片的通带半高宽、背景透过率和峰值透过率给通道线性带来的影响进行了分析和计算。结果表明,滤光片的通带半高宽、背景透过率和峰值透过率对通道的线性均有较大的影响。研究结果为研制高性能的瞬态光学高温计时选取合适的滤光片提供了依据。     

星载成像光谱仪杂散光测量

星载成像光谱仪用于获得高准确度的光谱遥感数据,而杂散光是影响其光谱测量准确度的重要因素之一.介绍了此类成像光谱仪杂散光的定义、来源和危害,在比较截止滤光片法、光谱法、谱杂散光系数法等光谱仪器常用杂散光测量方法优缺点的基础上,论述了使用杂散光影响因子描述光谱仪杂散光的可行性和优越性.最后,介绍了使用窄带滤光片测量星载成像光谱仪杂散光影响因子的测量系统组成、测量步骤和测量结果,并分析了测量方法的不确定度.结果表明：杂散光影响因子能有效描述光谱仪的杂散光特性,测量结果与光源、探测器等测量条件无关;窄带滤光片法测量不确定度为0.646%（置信概率约为95%）,能满足星载成像光谱仪杂散光测量的工程需要.     

星载成像光谱仪杂散光测量

星载成像光谱仪用于获得高准确度的光谱遥感数据,而杂散光是影响其光谱测量准确度的重要因素之一.介绍了此类成像光谱仪杂散光的定义、来源和危害,在比较截止滤光片法、光谱法、谱杂散光系数法等光谱仪器常用杂散光测量方法优缺点的基础上,论述了使用杂散光影响因子描述光谱仪杂散光的可行性和优越性.最后,介绍了使用窄带滤光片测量星载成像光谱仪杂散光影响因子的测量系统组成、测量步骤和测量结果,并分析了测量方法的不确定度.结果表明:杂散光影响因子能有效描述光谱仪的杂散光特性,测量结果与光源、探测器等测量条件无关;窄带滤光片法测量不确定度为0.646%(置信概率约为95%),能满足星载成像光谱仪杂散光测量的工程需要.     

光谱仪杂散光的测量方法

一、紫外和可见光波段的光谱 仪杂散光的测量 光谱仪是进行光谱分析的重要工具.此外,还可以利用光谱仪输出的单色光进行其他工作,例如反射率和透过率的测定等.但是当光谱仪用于定量测量时,会遇到光谱仪的杂散光问题.光谱仪的杂散光就是光谱仪输出的、正常通带以外的光辐射.由于光谱仪存在这部分杂散光辐射,因此给测量带来了误差.目前人们对紫外和可见波段的光谱仪杂散光的测量已经作了一些工作.测量方法归纳起来主要有:(1)测量截止滤光片透过率的方法[1];(2)级数透过率方法[2];(3)光学方法[3];(4)卷积计算的方法[4].现分别介绍如下:1.测量截…     

Spectral filtering of femtosecond laser pulses by interference filters

Phase properties of optical thin film interference filters are discussed from the aspect of their usage for phase-error free wavelength separation of broadband femtosecond laser pulses. It is shown that both transmissive or reflective interference filters with high contrast ratios exhibit high cubic phase shifts on transmission or reflection, respectively, causing intolerable distortion in the temporal pulse shape. We show, however, that high efficiency wavelength separation of broadband femtosecond laser pulses can be achieved by using low contrast, properly designed reflective optical interference filters directly built into the cavity of the broad spectrum, femtosecond pulse lasers or parametric oscillators. For demonstrative purposes, we implemented the idea for a Kerr-lens mode-locked Ti:sapphire laser, and obtained two-color, inherently synchronized, unchirped, femtosecond pulse outputs from a single laser oscillator.     

The 650-nm variable optical attenuator based on polymer/silica hybrid waveguide

Visible light variable optical attenuators(VOA) are essential devices in the application of channel power regulation and equalization in wavelength-division multiplexing cross-connect nodes in plastic optical fiber(POF) transmission systems.In this paper, a polymer/silica hybrid waveguide thermo–optic attenuator based on multimode interference(MMI) coupler is designed and fabricated to operate at 650 nm. The single-mode transmission condition, MMI coupler, and transition taper dimensions are optimized through the beam propagation method. Thermal analysis based on material properties provides the optimized heater placement angle. The fabricated VOA presents an attenuation of 26.5 dB with a 21-mW electrical input power at 650 nm. The rise time and fall time are 51.99 and 192 μs, respectively. The time–stability measurement results prove its working reliability.     

High-speed bridges for fiber optic local area networks

Progress in optical fiber communications allows ever-increasing channel capacity for local area networks (LANs). However, there are still many problems to solve with respect to bridges interconnecting these LANs, which constitute a system bottleneck. To eliminate the bridge bottleneck in the interconnection of fiber optic LANs, a high-speed bridge using optical technology is proposed. The proposed optical bridge uses bistable optical devices, such as interference filters, as essential components of its design. As these devices can be easily fabricated, the implementation of this optical bridge is feasible.     

具有鲁棒性的矩形窄带滤光片的自动设计

分析了用于WDM光纤通信系统的全介质多腔窄带滤光片的膜系结构特点及其所必须具备的光学特性,提出了一种利用最优化方法的原理,通过计算机寻优来自动完成其膜系设计的方法;构造了合理的评价函数,编制了可自动搜索既满足设计目标、又具有鲁棒性的最优化膜系的计算机程序;使用本程序所设计出的多腔窄带滤光片具有较小的纹波系数和较好的矩形度,可满足WDM光纤通信系统对其分波/复波器的要求.     

A novel reconfigurable radio-over-fiber system based on flexible optical devices

In this paper, a reconfigurable Radio over Fiber system based on optical switches, optical multimode interference power splitter and tunable optical filters is designed, which can achieve quadrature phase shift keying wireless modulation in optical domain and switch carrier frequency between 30 and 60 GHz. The scheme can make good use of bandwidth resource and realize signal transmission in fiber within 10 km.     

Minimum Channel Spacing in an OFDM CPFSK Optical Coherent System

Channel spacing in optical frequency-division multiplexed (OFDM) coherent optical systems with continuous-phase frequency-shift-keying (CPFSK) is obtained both theoretically and experimentally. The bit error ratio is derived taking into account the non-Gaussian interference statistics, expressed in terms of the Marcum Q-function, and the sensitivity penalty is reported as a function of the signal-to-interference ratio and the channel spacing for different IF filters. Laboratory demonstration of a state-of-the-art fully engineered two-channel 2.5 Gb s^-1 CPFSK coherent system at 1550 nm has been performed, showing an inter-channel crosstalk measurement in agreement with the theoretical analysis. A 0.1 nm channel spacing is experimentally confirmed.     

43 Gbit/s x 54 ch Transmission with Dense 75 GHz Channel Spacing in NRZ Modulation Scheme

We demonstrated 2.16-Tbit/s (43 Gbit/s x 54 ch) WDM transmission over 600 km of standard single-mode fiber with high spectral efficiency 0.53 bit/s/Hz using optimized optical mux/demux filters for 75-GHz channel spacing in a simple NRZ modulation scheme.     

Phase filters for correlators with incoherent light

Optimized phase filters can be designed and incorporated into hybrid electronic-optic correlators that exploit incoherent light. These filters lead to high optical efficiency and little, if any, loss of information that normally result from discarding amplitude data. The optimization procedure was experimentally tested by recording optimized filters in photo resist and incorporating them into the correlator. The optimization algorithm, the filter recording procedures, and the experiment correlation results demonstrating the efficacy of our design are presented. These results are superior when compared to those of correlators using holographic filters.     

彩色图像的非相干光相关识别

提出一种用非相干光系统识别彩色图像的方法,将脸色图像分解成三个单色像处理,设计一可实现的仅相位光学传递函数,对其进行带能优化,人而提高信噪比并使相关峰锐化,通过一对滤波器来合成该光学传递函数,获得了采色图像相关识别的实验结果。