La_3Ga_5SiO_(14)声光可调谐滤波器设计

分析了La3Ga5SiO14(简称LGS)既可以做成同向声光可调谐滤波器,又可以做成大孔径非同向声光可调谐滤波器。推导出超声波频率f和光波波长λo的调谐关系;计算出滤波器的光谱分辨率R和集光能力δiθ;光入射角iθ与衍射角θd、声入射角θa之间的关系。为LGS声光可调滤波器的实用化设计提供了充分可靠的理论依据。把LGS与TeO2声光可调滤波器的光谱分辨率和集光能力做了比较,认为LGS设计成同向声光可调谐滤波器既简便又实用。     

AOTF成像光谱仪光学系统的最优方案选择

基于声光可调谐滤波器（AOTF）的成像光谱仪是一种新型的成像光谱仪,它除了具有一般成像光谱仪的二维空间信息与一维光谱信息外,还能获得目标的偏振信息。在实际应用中AOTF可接收的光束孔径角一般不大于5～6,因而受到所采用声光晶体可接收角度的限制,AOTF光谱成像仪的光学系统不能同时兼顾大孔径与大视场。要求AOTF成像光谱仪视场满足128128像元,TeO2晶体尺寸为10 mm10 mm,根据声光可调谐滤波器成像光谱仪光学系统的特点,分析比较了2种光学系统总体方案,最终将系统的孔径光栏放置在晶体上,TeO2晶体尺寸限制了孔径光栏的尺寸,晶体可接收的角度决定了系统的视场角,提高了能量利用率,获得较高的图像信噪比。     

两级串联声光可调谐滤波器旁瓣抑制的研究

阐述了偏振依赖的共线型和偏振无关的准共线型声光可调谐滤波器的滤波原理,进而导出了两级滤波的转换特性表达式;通过理论计算说明了两级声光可调谐滤波器能够有效地抑制旁瓣;最后,将两个单级的声光可调谐滤波器级联成两级滤波器,进行了旁瓣抑制的实验.实验结果表明,旁瓣被抑制到-19 dB,并且3 dB带宽也得到一定程度的压窄. 关键词： 集成光学 声光可调谐滤波器 旁瓣抑制     

声光可调谐环形腔掺铒光纤激光器

应用单级偏振无关的准共线型声光可调谐滤波器为调谐元件,实现了环形腔掺铒光纤激光器的连续可调谐激光输出.简要阐述了与偏振无关的准共线型声光可调谐滤波器的工作原理,对其频移补偿原理进行了分析.实验研究得到:当抽运功率为13mW时,中心波长为1550nm的激光输出功率为322μW,阈值抽运功率在7.65mW左右,斜率效率约为6.02%;并获得了38nm带宽(1524.7—1562.4nm)的连续可调谐激光输出.     

关于非同向二氧化碲声光可调谐滤波器的实验研究

介绍了一种具有大光入射角度的非共线TeO2声光可调谐滤波器(AOTF)的结构和特点,并对实验样品的特性进行了测量。实验结果表明,该器件在100nm的可调谐范围内有效衍射效率可以达到96%,带宽小于2nm,试验结果与理论值一致。这种AOTF将用于动态光分插复用器(OADM),在未来光网络系统中起到重要作用。     

通信用声光可调谐滤波器

TN65 2004064495 通信用声光可调谐滤波器=Acousto-optic tunable filters used in communication[刊,中]/刘维(北京理工大学信息科学技术学院光电工程系.北京(100081)),崔建民…∥光学技术.—2004,30(4).—394-397 介绍了以LN为基底的集成型和以TeO_2为材料的体型通信用声光可调谐滤波器(AOTF)的工作机制,并对     

声光可调谐滤波器(AOTF)消色散设计

介绍了非共线声光可调谐滤波器的构成及基本原理,计算了非共线声光可调谐滤波器衍射出的±1级衍射偏振光的偏转角,采用在光路中添加光楔的方法补偿非共线声光可调谐滤波器晶体色散引起的图像漂移.分析结果表明使用TeO_2材料设计的光楔在楔角为7.6°的时候可以控制图像漂移在一个像元以内,并在400～900 nm的工作波段范围内满足稳定成像的要求.     

基于光纤叠栅的全光纤声光可调谐滤波器的特性分析

本文提出了一种基于光纤叠栅的全光纤声光可调谐滤波器, 与普通光纤布拉格光栅型全光纤声光可调谐滤波器相比, 该滤波器能够对光纤叠栅的两个中心波长进行同步调制. 理论分析了声波频率和声致应变幅度对基于光纤叠栅的全光纤声光可调谐滤波器的传输光谱的影响, 结果表明, 各阶次反射峰分别以两个主反射峰为中心呈对称关系, 且主反射峰与其所调制出的次反射峰之间的波长间隔与声波频率成正比, 而两个主反射峰所调制出的同阶次反射峰之间的波长间隔与声波频率无关; 声致应变幅度主要影响主反射峰及次反射峰的反射率的变化. 实验中, 分别测试声波频率为390 kHz和710 kHz的基于光纤叠栅的全光纤声光可调谐滤波器的传输光谱, 实验结果的变化趋势与仿真分析结果相一致.     

窄带集成声光可调谐滤波器的研制

利用模式耦合理论分析了声光模式转换,并对声光可调谐滤波器的滤波带宽、调谐范围、驱动功率等性能参数进行分析计算。设计并制作出窄带集成声光可调谐滤波器(IAOTF)样品,搭建相应的IAOTF测试平台,得到中心波长在1.55μm,滤波带宽达到0.85 nm,波长调谐范围达到80 nm,驱动功率低于40mW的IAOTF。并对进一步压缩滤波带宽和旁瓣效应提出了解决途径。     

二氧化碲非同向声光可调谐滤波器的设计分析

在分析非同向声光可调谐滤波器器件设计理论的基础上，同时考虑声光晶体的双折射和旋光特征，分析和计算了二氧化碲声光可调谐滤波器的超声波极角θａ和入射光波极角θｉ之间的关系以及超声波频率ｆａ和光波波长λ０之间的调谐关系。     

碲酸盐玻璃的拉曼光谱研究

本文测试了TeO2-ZnO和TeO2-BaO两种二元系统不同金属氧化物浓度下玻璃的拉曼光谱,通过比较这两种碲酸盐玻璃系统拉曼光谱的异同,表明碲酸盐玻璃系统中随着金属氧化物浓度的增加,使玻璃网络中的TeO4双三角锥向TeO3三角棱锥转化,并且在TeO2-BaO二元玻璃中出现了非桥氧键。同时初步研究了TeO2-ZnO-Na2O三元玻璃的拉曼光谱,发现当TeO2-ZnO二元玻璃中加入5mol%的Na2O时,其结构并没有发生显著的变化。     

入射光面转动TeO2声光偏转器

本文提出了入射光面转动的新型工作模式ＴｅＯ２声光偏转器，入射光面转动Ｋ波矢位在（１１）平面，（１１０）平面是（１１０）－（００１）面绕（１１）轴转动一定角度而得，这种器件的特点是，比通常的偏转器具有最高的衍射效率和更宽的动态范围。     

声光滤光器性能指标的计算和讨论

以可调谐声光滤光器为元件所制造的光谱分析仪,利用声光谱光器的电调谐分光作用,辅以计算机控制,以完成信息的实时处理,其中声光滤光器性能指标的好坏将直接影响光谱分析仪的设计制造本文对用不同切向的氧化碲晶体所制成几种声光滤光器的几项性能指标进行计算的讨论,使在设计制造光谱分析仪时对声光谱光器的声光和电性能先有一个总体认识,以减少不必要的实验和摸索。     

Enhancement of up-conversion luminescence properties in Yb~(3+)/Tm~(3+)/Er~(3+) tri-doped transparent oxyfluoride tellurite glass ceramics

<正>Optically transparent Er~(3+)/Tm~(3+)/Yb~(3+) tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO_2-15ZnO-7ZnF_2-3YF3-1.5YbF3-0.3ErF3-0.2TmF_3(mol%) is prepared by a conventional melting quenching and the subsequent heat treatment processes.The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron microscope measurement.Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated.The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment,and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment.     

Er3+/Yb3+共掺TeO2-Li2O-B2O3-GeO2玻璃系统的光谱性质和热稳定性研究

制备了Er³⁺/Yb³⁺共掺的70TeO₂-5Li₂O-(25-x)B₂O₃-xGeO₂（x=0,5,10,15,20 mol%）系列玻璃, 研究了玻璃的热稳定性能, 测试了玻璃的吸收光谱、荧光光谱以及Er3+离子4I13/2能级荧光寿命, 并根据McCumber理论计算了Er³⁺离子4I13/2→4I15/2跃迁的受激发射截面. 结果表明：随着GeO₂含量的增加, 玻璃的热稳定性逐渐提高, 荧光谱线半高宽（FWHM）保持在70 nm左右, 而荧光强度和Er3+离子4I13/2能级荧光寿命逐渐提高, 研究表明这种玻璃系统是一种具有应用潜能的宽带光纤放大器用的基质材料.     

Nonlinear optical properties of 75TeO2－20Nb2O5－5ZnO glasses doped with CeO2

Nonlinear optical properties of 75TeO_2－20Nb_2O_5－5ZnO glasses doped with CeO_2 have been investigated with a self-diffracted time-resolved degenerate four-wave mixing (DFWM) technique at different excitation intensities and lattice temperatures. The DFWM signal exhibits three peaks at higher excitation intensities, where a main peak appears at zero delay time and two rather weak side peaks are located symmetrically at the negative and positive time delay. Due to destructive interferences between the fifth- and third-order polarizations, the line-shape of the main peak around the zero time delay evolves from single peak into a double-peak structure with increasing excitation intensity. Two side peaks emerge at the positive and negative time delay and gradually intensify with increasing excitation intensity or lattice temperature, and their positions are independent of the pulse duration, temperature and excitation intensity, which are attributed to the many-body Coulomb interaction.     

Preparation and spectral characterization of new Er3+-doped TeO2－B2O3－WO3－ZnO－ZnS glasses

Erbium-doped TeO_2-based oxysulfide glasses have been prepared in argon atmosphere in graphite crucibles. The results of thermal analysis and spectroscopic properties of Er^{3+} have been studied in terms of sulfide influence. As a function of composition, we have measured principally the optical absorption, spontaneous emission, and lifetime of the materials. Judd－Ofelt theory was introduced to calculate bandwidth and emission cross-section of Er^{3+}. The results demonstrate that addition of sulfide in tellurite glasses results in broad emission spectra, with high emission cross-section, slightly low emission lifetime and a comparatively high thermal stability as pure oxide glasses.     

Comparative study of spectroscopic properties of Er^3＋／Yb^3＋-codoped tellurite glass and fibres under 980nm excitation＊

A tellurite fibre of TeO_{2}－ZnO－La_{2}O_{3}－Li_{2}O glass codoped with 20000 ppm ytterbium and 5000 ppm erbium was fabricated by the suction casting and rod-in-tube technologies. The absorption spectrum of Er^{3+}/Yb^{3+} -codoped bulk glass has been measured. From the Judd－Ofelt intensity parameters, the spontaneous emission probability and radiative lifetime τ_{rad} of Er^{3+}:{}^{4}I_{13/2}→{}^{4}I_{15/2} transition for the bulk glass have been calculated. The emission fluorescence spectra and lifetimes around 1.5μm, and subsequent upconversion fluorescence in the range of 500－700nm were measured in fibres and compared with those in bulk glass. The changes in amplified spontaneous emission with fibre length and pumping power was also measured. It was found that the emission spectrum from erbium in fibres is almost twice as broad as the corresponding spectrum in bulk glass when pumped at 980nm.