光纤光谱仪

Avantes公司研制的AvaSpec光纤光谱测量平台可应用于紫外 -可见 -近红外光谱区。其组件包括 1 4位多通道模数转换器、插件板上微处理器和USB/RS 2 32接口。具有 1 0 2～ 2 0 4 8个像元的光电二极管、CCD、CMOS探测器阵列可集成到光具座中。光具座的焦长为 45mm或 75mm ,适于 2 0 0～ 1 1 0 0nm波长范围的光谱测量 ,分辨率高达 0 1nm半高全宽。任选件包括紫外增强探测器镀膜件、狭缝及滤光片。该装置以 2ms积分时间同时探测 8个信道的信号。 (No.30 )光纤光谱仪…     

用于小型光谱仪列阵的微透镜光栅

目前光谱测量领域有两个主要趋势：小型化和平行光谱分析,对于波长递减或分析化学等应用来说更是如此。对于制造廉价、简易的组件系统来说,希望通过将若干功能组合进一个单元或一个单面来减少系统中的元件数目。因此精密光栅结构的全息记录与折射微光学件的制造技术结合颇具吸引力。图１　具有一个光栅表面的折射微透镜的ＳＥＭ成像我们在光致抗蚀剂中制作了折射微透镜列阵,并在列阵顶部以全息术记录了一个光栅（图１）。这就将光谱仪的两个主要光学功能,即光谱分离和光谱聚焦功能组合在一个图２　低压氙灯光谱图３　微光谱仪列阵系统的…     

基于光纤法布里-珀罗滤波器的便携式近红外光谱仪

介绍一种以光纤法布里-珀罗(FFP)滤波器为核心的便携式近红外光谱仪的设计方法。为克服FFP控制电压和扫描波长之间的迟滞和非线性效应, 实现光谱仪扫描波长的准确定位, 采用一组光纤光栅（FBG）的中心波长为参考, 利用粒子群优化（PSO）算法对每个FBG中心波长进行准确定位。在此基础上, 采用多项式拟合技术, 实现了在每一个FFP扫描周期内, 在线建立FFP扫描波长与其控制电压间的关系模型, 从而构建了一种准确度高、小型便携的近红外光谱仪。实验证明该光谱仪扫描波长范围为1490～1590 nm, 波长测量误差低于0.15 nm, 波长分辨率小于0.4 nm。     

微型光纤光谱仪的波长定标分析

为了提高光纤光谱仪的测量精度,采用标准汞氩灯谱线和最小二乘法的3阶线性拟合,取得了完整的波长定标方案。结果表明,算术平均误差小于0.167nm,标准差小于0.217nm,波长与像素的拟合相关程度较高;定标后波长不确定度优于0.11nm,误差小于0.15nm,波长重复性可达0.01nm。这一结果对提高光谱仪实际应用中的测量精度是非常有益的。     

近红外光纤光谱仪

金属会发生腐蚀现象。金属受腐蚀的程度一般都是靠检测人员通过肉眼检测的,这种检测多少有些主观性。因此,如果有一种能够测定金属衬底上局部或总的腐蚀程度和量的无损定量检测装置,那是非常理想的。     

一种近红外光纤布里渊光谱仪分辨率增强方法

对于研制的基于光纤受激布里渊效应的精密光谱分析仪,受激布里渊增益谱宽的存在限制了可用的最佳光谱分辨率,并造成受激布里渊增益系数与功率存在关联性。这些都会影响近红外光纤布里渊光谱仪的性能。针对上述问题,提出了一种光谱分辨率增强方法。采用两级受激布里渊过程级联,并结合待测光和泵浦光的功率调控,使得受激布里渊过程处于小信号、线性高增益区。结果表明,该方法能够实现约1.4倍的光谱分辨率增强效果,突破了原理理论限制,提升了近红外光纤布里渊光谱仪的性能。     

海洋光学推出高分辨率微型光纤光谱仪

随着NIRQuest512-2.5的推出,海洋光学（Ocean Optics www.oceanoptics.com）扩展了其近红外光纤光谱。NIRQuest512-2.5响应范围覆盖900nm～2500nm,非常适用于分辨率要求高的激光特性测量等应用。NIRQuest512-2.5采用滨松512像元的铟镓化砷（InGaAs）阵列检测器,覆盖范围900nm～2500nm,比之前的256像元的近红外系列,显着提高了光学分辨率。     

微小型光谱仪在激光波长测量中的应用

随着激光在工业加工、通信、测量以及医疗、科研等领域越来越广泛的应用,方便快捷地测量激光波长也正成为一种迫切的需求。本文以荷兰Avantes公司的微型光纤光谱仪AvaSpec-2048为例,介绍微型光谱仪在测量激光波长方面的应用。     

微型光纤光谱仪走向成熟

在不到10年的时间，微型光纤光谱仪已经从一种难以令人掌握的技术转化为一种实用技术，并已在很多领域得到广泛应用。目前，世界上已有10余家制造厂商生产各种微型光纤光谱仪，其中包括UV平台、UV—VIS、近红外、喇曼和质谱仪等，其特点是小巧而便携，售价均不超过5000美元。     

小型化高集成宽带光收发组件

当前分立光子器件的体积和成本严重制约着微波光子技术在雷达系统中的应用。受限于当前的集成能力和材料体系,微波光子单片集成芯片短时间内难以实现工程应用。为满足雷达等应用场景对高集成微波光子器件的迫切需要,研制了一种新型小型化高集成光收发组件。该组件采用光电异构集成封装技术,将MZM调制器芯片、微波芯片、探测器芯片以及光环形器、波分复用器进行高度集成,单模块体积仅为85 mm×35 mm×10 mm,与传统MZM调制器体积相当。实验结果表明,其性能可与传统分立元器件相媲美。在6~18 GHz范围内,组件能够实现±1.5 dB的平坦度,上行能够实现18 dB以上的增益,下行能够实现?1 dB以上的增益,且链路噪声系数小于30 dB,平面化、小型化设计使其能够应用于相控阵雷达、电子战等多种应用场景,具有广阔的应用前景。     

Coherent optical fiber transmission

Essential technologies for developing coherent optical fiber transmission systems are reviewed from the viewpoint of regenerative repeater spacing and transmission data rate improvements. After describing the system features behind these advantages, recent progress in individual device and system technologies is delineated. Such progress includes frequency stabilization and linewidth reduction of semiconductor lasers, optical phase or frequency modulation, AM and FM noise suppression in coherent receivers, optical polarization stabilization and control in signal transmission, and optical direct amplification. Also described is progress in coherent optical transmission experiments carried out in many laboratories. Finally, future problems are discussed on the basis of the current state of the art.     

Long-wavelength optical fiber communication

Recent research on long-wavelength lightwave communication utilizing the wavelength region between 1.3 and 1.6 µm is reviewed with an eye toward future system development. The attraction of the long-wavelength region is the availability of the ultimately low-loss and wide-band features of the silica fiber, where minimum loss is 0.27 dB/km at a wavelength of 1.3 µm and 0.16 dB/km at 1.55 µm. The single-mode fiber has found its first significant applications in long-wavelength systems. The specific characteristics of lightwave components are discussed with focus on physical fundamentals. The practical performance of fibers and lightwave devices is surveyed. The dynamic properties of long-wavelength laser diodes are discussed in relation to fiber characteristics. The noise characteristics of long-wavelength detectors are considered for the purpose of specifying the repeater spacing. Some system studies are reviewed, for example, 1.3-µm-wavelength lightwave systems, which have demonstrated bandwidth-distance products of about 40 GHz ċ km. Various approaches to extend the capacity of long-wavelength lightwave transmission are given. In the future, the 1.5-µm wavelength system could operate at the lowest loss wavelength region extending from 1.5 to 1.65 µm. Much higher performance, for example, bandwidth-distance products of 185 GHz ċ km, achieved by further continuation of research and development on lightwave sources as well as fibers. Because of the author's familiarity with work in Japan, that work is emphasized and most frequently cited.     

Silica-air double-clad optical fiber

A new design of the silica-air double-clad optical fiber is proposed. The fiber was prepared from an MCVD preform inserted into a supporting silica tube with a fluorine-doped connective element with a lower refractive index (Δn~-4×10^-3) and air as the second cladding. A numerical aperture as high as 0.3 was measured for the first cladding and for fiber lengths up to 50 cm. Although it is realized that the results are preliminary, the optimization of the fiber parameters promises a new all-glass design for double-clad optical fibers for high-power fiber laser applications     

Stretched-pulse optical fiber communications

We compare numerically long-distance propagation of two types of nonlinear pulses: a stretched pulse in a fiber with alternating normal and anomalous dispersion and a soliton in a fiber with uniformly anomalous dispersion. Numerical evaluation of timing jitter and Q factor reveals that stretched pulses can be propagated over longer distances than solitons with the same (averaged) fiber dispersion in the presence of weak fixed-frequency filtering. We also examine pulse-to-pulse interactions between stretched pulses and the influence of fluctuations of the fiber dispersion.     

耐弯曲单模光纤

本文讨论了光纤弯曲损耗及其主要影响因素,比较了目前采用的改善光纤弯曲损耗各种方法,对照G．652D光纤的特性,分析了两种新型耐弯曲光纤G．657A和B光纤的特性,指出了它们的应用场合。     

Mechanical optical fiber splices

Carefully designed mechanical optical fiber splices have achieved record field performance with respect to loss, productivity, and reliability. Design principles, mechanical splicing hardware, and field results are presented for multimode and single-mode, array, and individual-fiber mechanical splices.     

无线光通信

随着信息化社会的到来,通信技术得到了日新月异的发展,无线光通信具有施工、带宽、成本等多方面的优点,但仍然存在影响传输可靠性的一些问题,如果这些问题能得到解决,那么必能发挥最大潜能和优势,随着无线光通信技术的不断研究和完善,将会得到更加广泛的应用.