声光偏转效应在相干光检测的应用

为使现代电子侦察技术能适应信号密集、宽频谱、大动态的电磁环境, 提出了一种基于声光偏转器实现相关光信号处理的方法, 分析了射频信号频率变化与布拉格衍射角的关系, 讨论了声光偏转效应对信号频率的空间滤波特性; 在理论分析的基础上, 构建了在可见光范围内实现声光偏转的相干光信号探测的实验系统, 并通过计算机仿真对比, 验证了这种方法的可行性。实验表明, 采用波长为630 nm的单频激光, 带宽为200 MHz的声光偏转器, 其频率分辨率优于1 MHz, 频率信号的空间分离效果明显, 接收灵敏度和信噪比得到改善。     

Broad band acousto-optic deflector for holographic memories

A practical inexpensive mechanism for effecting improved Rayleigh resolution in a random access deflector without sacrificing its performance has been constructed. It comprises an acousto-optic deflector in the form of a flat transducer grating, made from a single piezoelectric platelet. The deflector steers the acoustic column to track the Bragg angle as the acoustic frequency changes.     

Acousto-optic deflector of depolarized laser radiation

An original acousto-optic deflector is based on the anisotropic diffraction in the paratellurite crystal. The deflector is characterized by a relatively high diffraction efficiency for depolarized laser radiation. The deflector consists of two sequential acousto-optic cells. Each cell deflects one of the orthogonally polarized components of the originally depolarized radiation. The first and second cells scan the low- and highfrequency parts of the angular interval, respectively. The simultaneous and independent operation of the cells makes it possible to use the entire optical (laser) power. A frequency band of 32 MHz is almost reached for depolarized radiation with a wavelength of 1.06 µm and the absolute angular interval is 50 mrad at a total efficiency of no less than 70%.     

用于声光相关/卷积器的双向声光偏转器

本文提出了用于声光相关／卷积器的双向声光偏转器的设计、制备和测试结果．两个通道的中心频率均为175MHz，带宽70MHz，衍射效率30％，渡越时间7μs．已在空间相干器时间相干器系统中得到应用．     

反常声电光偏转器

本文介绍的新型声光偏转器可提高传统光偏转器的带宽，制作了一个ＬＮ反常声电光偏转器，中心频率为６０ＭＨｚ测试结果表明，带宽由原来的２６ＭＨｚ提高到３７ＭＨｚ。     

基于声光效应的光束偏转控制理论研究

基于参量互作用观点及声光互作用原理,构建了入射光为高斯光并且存在声波吸收情况下的声光偏转器模型.基于此模型研究了超声波频率、声波功率和光束入射角对衍射光的影响.对比了有声波吸收和无声波吸收两种情况下上述三个参量对衍射光产生的不同影响.计算结果表明,同无声光吸收时相比,当存在声波吸收时,偏转器的衍射效率将减小,导致衍射波形畸变,光强峰值位置发生偏移.     

Prototype Demonstration of Discrete Correlation Processor-2 Based on High-Speed Optical Image Steering for Large-Fan-Out Reconfigurable Optical Interconnections

We present a discrete correlation processor-2 (DCP-2), which is an optical processor with reconfigurability of interconnection patterns for large-fan-out optical interconnection systems. To our knowledge, there is no reconfigurable optical processor satisfying the requirements for large fan-outs such as high-speed reconfiguration of interconnection pattern, high optical efficiency, and high contrast ratio, because existing spatial light modulators (SLM#x0027;s) lack at least one of these features. The DCP-2 architecture fulfills the requirements by using a hybrid configuration composed of a high-speed image steerer and a spatial light modulator, which work in a complementary manner to shorten the setup time of the SLM. We constructed two kinds of prototype demonstrators based on this architecture. In the experiment, reconfiguration speed of the DCP-2 prototype with shift-invariant optical interconnections, in which a liquid crystal SLM cooperated with a two-dimensional acousto-optic beam deflector, was about 26,000 times faster than that of the standalone SLM at the cost of 50#x0025; energy loss by the deflector.     

Acousto-Optic Deflector with a High Diffraction Efficiency and Wide Angular Scanning Range

A new acousto-optic deflector with a wide angular scanning range and a high diffraction efficiency has been studied. The device uses an additional deflector, which allows the angle of incidence of the input beam to be adjusted in order to fulfill the Bragg phase–matching condition over the entire scanning range of the main deflector. The characteristics of an anisotropic two-crystal deflector based on paratellurite crystals have been measured. It has been established experimentally that the operating bandwidth of the device is 32 MHz for a diffraction coefficient no less than 90%, which determines a light beam scanning angle of 50 mrad.     

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。     

An acousto-optical deflection system for use with multi-laser arrays in optical memories

Proposals have been made to utilise arrays of GaAs lasers in optical computer memories. For fast, random access to data the use of acousto-optical deflectors seems feasible. The number of lasers for use with each deflector is normally severely limited, because of the bandwidth limitation which is inherent in acousto-optic devices. This note describes a technique whereby the bandwidth limitation can be largely overcome, so that light from many lasers can be deflected by a single deflector.     

Rapid wavelength scanning based on acousto-optically tuned external-cavity laser diode

High-speed, wide-range wavelength scanning is demonstrated using a laser diode with an antireflection coating and an external cavity employing an acousto-optic deflector. The narrow spectral width of 0.2 nm observed in the experiment indicates the availability of a highly coherent laser beam. The scanning range of 15 nm under rapid modulation is confirmed in the prototype system. A tuning rate of more than 100 kHz is achieved without any mode hops. To the best of our knowledge, no such high-speed wavelength tuning based on an acousto-optical configuration has been demonstrated thus far.     

Acousto-Optic Commutation of Fiber-Optic Channels

Technical Physics - An acousto-optic commutator of fiber-optic channels based on a ТеО2 two-coordinate deflector has been proposed and realized. The commutator yields switching of...     

Design considerations of the acousto-optic light deflector

Theoretical analysis of the performance of the acousto-optic light deflector is described. Detailed calculations for LiIO₃-SF₆ glass structure including the influence of the bonding layer and Q-factor on the frequency response of the deflector are presented. A method of increasing the bandwidth in the presence of the bonding layer is given.     

Transverse grating-assisted narrow-bandwidth acousto-optic tunable filter

An experimental acousto-optic tunable filter that has a narrow spectral bandwidth (0.2 nm at 1550 nm) and a fast (10-micros) tuning capability with a continuous tuning range of approximately 50 nm is described. The tunable filter consists of an acousto-optic beam deflector with a diffraction grating whose grating vector is transverse to the direction of light propagation.     

An Acousto-Optic Polarization-Insensitive Two-Coordinate Deflector

Acoustical Physics - A new scheme of a polarization-independent two-coordinate acousto-optic deflector based on paratellurite crystals has been developed. One specific feature of the optical scheme...     

Tunable add/drop channel coupler based on an acousto-optic tunable filter and a tapered fiber

We report a tunable add/drop channel coupler based on an acousto-optic tunable filter and a tapered fiber. The coupling efficiency and central wavelength of the add/drop channel coupler are tunable by simply tuning the power and frequency of the driving radio frequency signal. Further possible improvements on the configuration are also discussed.     

Acousto-Optic Control of the Energy Profile of Laser Radiation

An acousto-optic shaper is developed for transformation of the Gaussian beam profile into almost rectangular profile. As distinct from lens devices, an acousto-optic device allows modification of the shape of the output beam in a fixed optical configuration using changes in radio control with relatively short response times of about 10 μs. The method is based on multibeam high-efficiency Bragg diffraction when the diffraction orders are overlapped with respect to angle. It is shown that the beam profile can be transformed into rectangular and more complicated profiles with an efficiency of no less than 80%. The experiments are performed using the TeO₂ crystal.     

Simultaneous cavity-enhanced and cavity ringdown absorption spectroscopy using optical feedback

We present a scheme of optical feedback cavity-enhanced absorption spectroscopy (OF-CEAS) including a fast optical switch to produce cavity ringdown spectra (OF-CRDS) simultaneously. This also works as a dynamically adjustable variable attenuator allowing to compensate for reduced signal levels in correspondence with absorption lines. For this, an acousto-optic deflector is used in a double-pass configuration to eliminate the single-pass frequency shift, which is incompatible with optical feedback. This is probably the most effective device providing the required fast response and the high extinction ratio necessary to perform clean ringdown measurements. The resulting direct comparison of OF-CEAS and OF-CRDS shows that these produce almost equivalent spectral data, with 0.3 % maximal difference at the top of an absorption line having a signal-to-noise ratio (S/N) of 3,300. OF-CEAS is largely winning on the short-term noise level while OF-CRDS appears to be more immune from interference fringes, delivering cleaner spectra after longer averaging.     

Acousto-Optic Deflector with Heat Removal from the Piezotransducer by Sound Insulation of a Heat Radiator

Acoustical Physics - A method is proposed for removing heat from the transducer of an acousto-optic deflector without substantial acoustic damping. The rear surface of the transducer and the...     

基于声光栅的变频条纹投射系统

针对三维形貌测量中结构光照明系统投影速度慢、结构复杂、在线集成困难的问题,提出了一种基于声光栅的变频条纹投射系统。该系统利用拍频信号驱动声光偏转器,在声光晶体中形成两个重叠的光栅,光源发出的激光以布拉格角入射,形成两束一级衍射光,经透镜聚焦形成光强按正弦规律分布的结构光条纹。建立了数学模型,同时提出了一种新的相位凝固技术,使条纹空间频率和相位的变化规律得到了很好的解释。该系统结构紧凑、体积小,全电控可调,无任何机械移动部件,具有条纹投影速度快、精度高、动态可编程的特点。应用该系统对石膏像形貌进行测量,获得了用于三维成像的相位图。该投射系统对于解决复杂几何形状物体的三维测量问题具有较高的工程应用价值。