光纤传输用的磁光隔离器

本文报导了光纤通信用光隔离器的研究工作.隔离器由稀土铁石榴石法拉第旋转器及两只方解石棱镜组成.在波长为1.15微米时,器件插入损耗为2.4分贝,隔离比为34.8分贝.讨论了使用不同的复合稀土铁石榴石材料及采用不依赖偏振光技术对器件性能的改进.     

LiNbO3质子交换光波导偏振器的研究

研制了632.8 nm光波段X切Y传Ti扩散铌酸锂质子交换光波导偏振器.从理论上分析了钛(Ti)扩散及质子交换(PE)LiNbO3波导折射率改变机理,以及影响器件性能的各种因素.实验结果与理论计算符合良好,达到了集成光路中对器件的偏振要求,为其他类型偏振器的研制提供了理论依据.     

太赫兹波段硅片组偏振器的设计及其应用

为了克服目前应用于太赫兹波段的偏振器件成本较高、加工难度较大、易产生法布里-珀罗效应回声等缺点,利用平行堆叠硅片的布儒斯特效应,设计了一种新型的适用于太赫兹波段的硅片组偏振器件。根据不同油品中手性化合物浓度不同对太赫兹波的旋光性不同的原理,用该偏振器对97#汽油、柴油及其混合油样品的旋光性进行测量,实现了混油检测。结果表明,设计的偏振器消光比高于1059、透过率高于99%、适用频段为0THz~3THz; 利用硅片组偏振器对97#汽油、柴油以及两种按不同体积分数混合的油品进行旋光性的测量,实现了对油品的定性和定量检测。该偏振器件的设计满足太赫兹波段的偏振需求。     

1.3μm波长金属膜波导偏振器的研制

文章针对Ｔｉ扩散ＬｉＮｂＯ３波导１．３μｍ波长偏振器的制作，论述了单模ＴＥ波传输的波导偏振器的器件结构设计，理论分析及制作方法。采用的优化结构ＭｇＯ／Ａｌ覆盖波导偏振器其ＴＭ波的消光比达４０ｄＢ以上，ＴＥ波附加损耗〈１ｄＢ，器件综合消光比〉３５ｄＢ，结果与理论计算相近。     

双折射闪耀光栅型偏振器的研制

本文给出一种利用衍射和双折射的复合作用使光束起偏振的双折射冷淡耀光栅型偏振器的结构设计和实验制作，该种器件具有棱镜偏振器和二向色生偏振片二者的主要优点，样品器件已在实验中制出，器件的消光比大于２×１０＾－４，并还有很大的提高余地，该种器件是一种具有良好应用前景的新型偏光器件。     

深紫外光栅反常偏振器件的设计与分析

为实现金属光栅偏振器件在光刻机偏振照明系统中的应用,基于共振域光栅的反常偏振效应,提出一种以二氧化硅为基底、铝与氟化镁作为栅线材料的介质-金属光栅偏振器。与传统的亚波长金属光栅偏振器相比,该偏振器的光栅周期接近入射波长(0.19～0.20μm),表现出透射TE偏振光、反射TM偏振光的反常特性。由时域有限差分算法(FDTD)的数值模拟结果可得,当波长为0.193μm的光垂直入射时,该光栅偏振器对TE偏振光的透过率大于60%,偏振消光比大于180。与具有相同结构参数和栅线材料的单层金属光栅偏振器相比,该介质-金属光栅偏振器在深紫外波段具有良好的偏振性能,TE偏振光透过率提升了约10%,偏振消光比提升了4.5倍左右(在0.193μm波长下)。     

聚能叉指换能器波束压缩声表面波卷积器

本文叙述采用聚能叉指换能器和△V/V波导进行波束压缩以提高声功率密度,制作在YZ-LiNbO_3基片上的声表面波卷积器。在保持器件原有性能的条件下提高了卷积效率,实验测得卷积效率为-71—-72毫瓦分贝;动态范围为45—50分贝。这种卷积器可适用于大时-带积。     

石英双光楔退偏振器研制

随着激光技术的发展,需用单色光退偏振器的地方越来越多。国际上对退偏振器研究早有报道,我们也曾多次报道过利用方解石、石英研制以四种单元结构的此类器件,但都存在着一个光束偏折问题,限制了它的应用范围.新研制的单色光石英退偏振器为二元结构,由两双折射光楔光轴正交,斜面并列胶合在一起而成,对样品测试发现,退     

光纤陀螺用单Y 1.3 μm LiNbO3集成光学器件

用退火质子交换法制作了用于光纤陀螺的集分束器、相位调制器、偏振器为一体的LiNbO3集成光学器件 ,介绍了器件设计考虑 ,简述了器件的工作原理 ,并对其性能进行了分析     

金属-电介质复合材料中非局域效应诱导的偏振分光器（英文）

基于具有强非局域效应的金属-电介质多层膜结构提出了三种偏振分光器.当多层膜结构的平均介电常数为零时,横电偏振电磁波对应的等频率曲线为一很小的圆,而横磁偏振电磁波对应的等频率曲线则为两支抛物线,这是由表面等离激元诱导的非局域效应引起的.利用该多层膜结构在不同偏振电磁波下等频率曲线表现出巨大差异这一特性,提出了三种偏振分光器,其中包含厚度远小于波长的超薄偏振分光器.这些结果有望在偏振选择吸收体以及集成光子器件中有潜在应用.     

0-3型压电复合材料的电晕放电极化

金属单针电晕放电极化０—３型压电复合材料的工艺条件是：电晕放电电压Ｖ＝８．５ｋＶ，极化温度Ｔ＝１３０℃，极化时间ｔ≥４０ｍｉｎ。利用旋转电晕放电对大面积０—３型压电复合材料进行极化。结果表明：这种极化方法可达到普通油浴高压直接极化的效果，而且可以对大面积压电复合材料进行极化。对于７０μｍ厚的大面积０—３型压电复合材料，极化后，其压电系数ｄ３３值达到３５ｐＣ／Ｎ。     

Rapid polarizing field cycling in magnetic resonance imaging

We describe the electronics for controlling the independently pulsed polarizing coil in a prepolarized magnetic resonance imaging (PMRI) system and demonstrate performance with free induction decay measurements and in vivo imaging experiments. A PMRI scanner retains all the benefits of acquiring MRI data at low field, but with the higher signal of the polarizing field. Rapidly and efficiently ramping the polarizing coil without disturbing the data acquisition is one of the major challenges of PMRI. With our modular hardware design, we successfully ramp the 0.4-T polarizing coil of a wrist-sized PMRI scanner at up to 100 T/s without causing image artifacts or otherwise degrading data acquisition.     

LCD的偏光片工艺技术

介绍LCD偏光片的工作原理、基本结构、生产工艺和基本性能技术指标，并详细讲述了LCD制造工艺中，贴偏光片的作业流程。     

利用复振幅设计10.6μm偏振分光膜

为了得到10.6 μm处偏振分光膜,采用薄膜光学的复振幅理论,利用受抑全内反射原理对传统的偏振分光膜的设计思想进行了改进,即通过抑制复振幅反射率为0,得到各膜层厚度.以10.6 μm光波入射,仿真了不同入射角条件下的膜层厚度关系曲线,通过对曲线簇交叉点的取值,构建了偏振分光膜系的初始结构,通过Macleod优化设计了10.6 μm红外偏振分光膜,所设计的偏振分光膜在10.6 μm处,P偏振光透射率达到了92%,S偏振光反射率达到了93%,入射角范围是65～75°(玻璃中),反射偏振光消光比10~2～10~3.结果表明:此方法在偏振分光膜设计中有重要的应用价值.     

光致各向异性记录介质偏振全息图的透射矩阵

在给定参，物光波的偏振态和位相差的关系以后，用光致各向异性介质记录的偏振全息图的光学常数分布便被确定。这样，可以把偏振全息图看作是一种复杂的偏振元件，按照偏振元件的矩阵理论，可以求出偏振全息图的透射短阵，透射矩阵与照明光的琼斯矢量相乘，使可以求出再现光波的琼斯矢量。     

A Wide-Band UHF Traveling-Wave Variable Reactance Amplifier

The techniques developed for designing periodically loaded traveling-wave parametric amplifiers using variable-reactance diodes are described in detail. An amplifier was built and tested with two different sets of eight diodes. The performance of the amplifier with each set of diodes agrees substantially with the theoretical predictions, the measured noise figures being about 1.2 db higher than the theoretical values in each case. The gain of the second amplifier varied from a minimum of 6.7 db to more than 13 db over the band from 550 to 930 mc, with a measured noise figure of 2.3 db for wide-band noise inputs in the middle of the band, corresponding to about 4.9 db for single-frequency inputs.     

偏振器件在通信和传感中的应用

偏振器件是光纤通信和光纤传感系统中的重要器件.随着光纤光学的发展,偏振器件的应用越来越广泛,并且开发出了许多新的类型.为此总结了偏振器件在光纤通信及光纤传感领域中的应用,并对偏振器件的研究方向作了展望.     

UHF Strip Transmission Line Hybrid Junction

A hybrid junction has been developed using a symmetrical strip transmission line for application in the UHF range. It has a frequency band of +- 20 per cent where the input voltage standing-wave ratios at all ports are less than 1.26 (2 db), the power divisions are within 0.1 db, and the difference in power between the series input and parallel input ports is less than 0.3 db. The isolation is greater than 40 db and 24 db, respectively, for the two pairs of conjugate ports. These circuits are relatively small, light-weight, simple to build and reproduce, and are inexpensive. The approximate equivalent circuit of the configuration assuming transmission in the TEM mode is presented. The results of the analysis and the important features in the design and fabrication and a few modifications of the configuration are discussed.     

Broad-Band Isolators and Variable Attenuators for Millimeter Wavelengths

A longitudinally magnetized rod of ferrite has been used as a dielectric waveguide which provides Faraday rotation independent of frequency in the band from 50 to 60 kMc. This rotator has been incorporated into broad-band isolators with forward losses of 1 db and reverse losses greater than 30 db with return losses of approximately 20 db over the band. It has also been used in a variable attenuator with a minimum loss of 1 db and a maximum loss greater than 30 db which is essentially constant over the band. Advantages of this type of rotator at millimeter wavelengths include bandwidths in excess of 20 per cent, low field requirements (25-50 /spl oelig/), relatively large dimensions, the use of common ferrites, and the absence of conducting waveguide walls which permits rapid switching of the control field. The last feature has been utilized in an automatic power leveling system capable of removing variations of several kc frequency content from the swept output of a millimeter wave BWO.     

Mismatch Errors in Cascade-Connected Variable Attenuators

The treatment of mismatch errors is extended to cover variable attenuators cascade-connected in a system which is not free from reflections. The method of analysis is applicable to any number of cascaded attenuators, but only the analysis of two and three variable attenuators in cascade is presented. Graphs are given to aid in estimating the Iimits of mismatch error. In an example, which is considered representative of rigid rectangular waveguide systems, the limits of error are: for two attenuators in cascade, 0.19 db in a 3-db measurement, and 0.17 db in a 40-db measurement; and for three attenuators in cascade, 0.25 db in a 40-db measurement, and 0.23 db in a 75-db measurement.