光纤-声光外差及变频器

机电部二十六所研制的光纤-声光外差及变频器最近通过了技术鉴定。该器件集声光技术、光纤及耦合技术、锁相环路技术等为一体,制作出了抗干扰能力强、动态范围宽、信噪比高、差频稳定性和选择性好的     

声光器件及其在军事方面的应用

通过声光器件原理、结构和特性的回顾,着重介绍体波声光器件在实时信息处理、光纤传感技术及光计算技术等军事领域的应用.     

光外调制——全光纤声光调制器的研制(下)

4 全光纤声光器件的研制 结合光纤声光互作用理论,我们设计了一种可拆除的全光纤声光器件——表面波声光器件。将声     

一种高速光纤声光调制器

该文介绍了应用于光纤传感系统中的高速光纤声光调制器的设计和应用。分析了影响光纤声光调制器调制速度的因素,介绍了高速光纤声光调制器的设计方法。最后采用氧化碲(TeO_2)晶体和小束腰光纤准直器得到工作波长1 550nm、光脉冲上升时间23.9ns、插入损耗2.9dB、通断消光比53dB的高速光纤声光调制器。     

可实现连续激光-脉冲转换的全光纤声光耦合环形谐振腔

研究了光纤声光耦合环形腔独特的谐振特性。结果表明利用光纤声光耦合器的移频与滤波特性 ,可研制成一种全新结构的光纤声光耦合环形谐振腔。从理论和实验上证明了 :基于腔内累积声光移频分量的多光束干涉 ,光纤声光耦合环形谐振腔可将注入的连续激光将转换为脉冲列输出。     

单模光纤中声波传输的衰减及其对光纤声光滤波器工作特性的影响

研究了声波在光纤中的衰减对光纤声光滤波器性能的影响 ,提出了通过测量不同长度光纤的声光模式转换效率测量声波在光纤中传输衰减的新方法 ,指出声波的衰减造成声光耦合效率降低并使声光滤波器的带宽展宽和消光比变差 ,带宽展宽的大小近似与声波衰减系数的平方成正比     

基于磷化铟材料的高速光纤声光调制器

该文介绍了一种基于磷化铟(InP)材料制作的高速光纤声光调制器,分析了高速光纤声光调制器设计原理。通过仿真得到高速光纤声光调制器的设计参数,并制作了光波长为1 550 nm的300 MHz光纤声光调制器。测试结果表明,该光纤声光调制器的插入损耗为2.8 dB,消光比为49 dB,光脉冲上升时间为6.34 ns。     

四川压电与声光技术研究所光纤传感器概况

四川压电与声光技术研究所是机械电子工业部中国电子工业总公司所属的压电与声光技术的专业研究所。从1972年开始筹建声光技术研究室,经过近20年的创业和发展,目前已拥有一支从事光学材料、声光器件、光纤传感器、电子线路、导波光学、薄膜光学、光电测量、光学加工等门类齐全,自成体系的科技队伍。     

用于光纤声光器件的超声换能器与模式转换器

研制了一种可用于全光纤声光器件的超声换能器,设计了由光纤和换能器构成的纵-弯模式转换系统,并将所作的换能器和模式转换系统应用于光纤声光可变衰减实验。结果表明,设计的换能器既有较宽带宽又有较高发射效率,完全可以满足全光纤声光器件的需要。     

单模光纤声光滤波器带宽特性的研究

研究了基于匹配包层 (MC)、色散位移 (DS)和色散补偿 (DC)单模光纤的声光滤波器的带宽特性。研究结果表明利用具有比较强的波导色散的光纤可以实现窄带声光滤波器。为了描述光纤的色散特性与滤波器带宽的关系 ,定义了一个新的表征光纤色散特性的参数 N并提出了通过测量光纤声光滤波器峰值波长调谐度来测量色散参数N的新方法。采用商用DC光纤在实验上实现了带宽为 0 5 5nm的半高全宽 (FWHM)全光纤声光滤波器。     

声光Q开关

本文介绍了声光Q开关的工作原理及工作于1.06μm光波长,50MHz超声频率,4mm通光孔径的布喇格型熔石英介质声光Q开关的设计与制作。     

新型激光腔内声光倒空器的研制

文中描述了新型声光腔内倒空器的工作原理并介绍了工作波长为 1 0 6 μm ,超声频率为80MHz的Y36°切铌酸锂换能器 ,内调制频率在 1～ 30kHz内可调 ,通光孔径为 5mm的布拉格型熔石英介质声光倒空器的设计。制作、测试和评价了激光腔内声光倒空器。当高频驱动源功率 >2 0W时 ,衍射效率 >50 %。该器件在Nd3+YAG激光系统实验中获得了腔内倒空的结果     

Acoustooptic signal processing and computing

Acoustooptic techniques have been used to perform computationally intensive signal processing operations and form subsystems of larger signal processing systems. Key aspects of acoustooptic devices and of the range of possible signal processing applications, including the advantages of acoustooptic implementation, are reviewed. Developments that improve acoustooptic device performance, increase system dynamic range such as by reduction of optical crosstalk from optical scatter and wavefront error, and implement data reduction operations that allow easier interfacing into a larger signal processing/computation system are described     

Compact all-fibre on-line power monitor via core-to-cladding modecoupling

An on-line all-fibre power monitor is demonstrated in which light from the core mode is first coupled to the cladding mode using an acoustooptic tunable filter, and then coupled to an InGaAs pin detector bonded to the fibre. Detection efficiency for different cladding modes and fibre cladding diameters are presented     

Cascaded acoustooptic/fiber Fabry-Perot filter with finesse over2000

A compound optical filter consisting of an integrated acoustooptic filter in series with a fiber Fabry-Perot filter possesses a very high effective finesse of over 2000 as well as the unique multichannel passband capability of the acoustooptic filter. The fine-grain element in this pair is a narrow (0.5-Å) passband Fabry-Perot filter, and the coarse-grain element is a wide tuning range (130-nm) polarization-independent integrated acoustooptic filter. The composite device has the narrow passband of the Fabry-Perot, the wide tuning range of the acoustooptic filter and the tuning speed of the faster acoustooptic filter (5 μs)     

The influence of external frequency shifted feedback on a DFB semiconductor laser

To investigate the possibility of optical isolation of a semiconductor laser using acoustooptic interaction, the influence of frequency shifted feedback on a DFB laser was studied experimentally. The isolation concept is based on a frequency shift of the laserlight by means of an acoustooptic Bragg deflection. This concept offers the opportunity of optical integration when Surface Acoustic Waves are used. In the experiments, a clear difference in laser performance between regular feedback and frequency shifted feedback was observed.     

High strain-induced wavelength tunability in tapered fibreacousto-optic filters

A study into the effect of the strain on a tapered fibre acoustooptic filter is presented. The centre wavelengths of the resonances are dramatically affected by strain: >500 nm tunability range has been obtained for a maximum applied strain of 1.3×10^-2     

Acoustooptic interactions and devices

A review of recent advances in the understanding of the interaction of light and ultrasonic waves in solids and liquids is presented, emphasizing the Bragg diffraction regime wherein the diffracted optical energy is confined near one angular direction. The usefulness of optical beam probing techniques, using laser light sources, for investigating such subjects as ultrasonic attenuation and diffraction, acoustic nonlinear phenomena, magnetoelastic interactions, and photoelastic properties of materials is described. The application of the acoustooptic interaction for the design of devices intended to perform optical information processing functions is also mentioned. Present applications include optical modulators, switches, sequential scanners (such as are useful for television display), random access optical deflectors, and optical correlators. An attempt is made to describe the assets and liabilities of acoustooptic devices and to speculate concerning their future in the practical world.     

Tunable acoustooptic reflection filters in LiNbO3without a Doppler shift

A proposal is presented for an acoustooptic filter in LiNbO₃ without the Doppler shift, which is normally present in acoustooptic filters and which is undesirable as an intracavity element. This tunable filter has a significantly wider tuning range than previously demonstrated electrooptic filters. A structure incorporating an interdigital acoustic transducer, polarization filter, and single-mode optical waveguide is shown. The design presented works by cascading two acoustooptic filters with an intermediate polarizer, where the Doppler shift experienced in the first filter is precisely compensated for in the second filter. Hence, the output light of the two cascaded acoustooptic filters is not shifted in frequency, thus making the device suitable for applications inside a laser cavity. The filter with intermediate polarizer can be integrated with a single-mode waveguide and requires only a single interdigital acoustic transducer. Crystal symmetry and acoustic power considerations are treated in detail