Abstract

An acousto-optic delay line (AODL) is an effective tool for signal processing in the time domain. A smoothly controlled signal delay over a wide time interval allows high-performance radar simulators to be built based on an AODL. This paper considers the AODL’s design and marks the parameters that determine the limit of using its capabilities. The features of the photoelastic interaction in an AODL are investigated for the case when the duration of the input pulse is shorter than the time of crossing the optical beam by an elastic wave packet. It is found that under these conditions the duration of the output response is determined by the time taken to cross the optical beam by an elastic wave packet and does not depend on the duration of the input action. It is shown that the AODL response to the input action in the form of a rectangular pulse is determined as the sum of three terms. In this case, the first term is determined by the process of entry of the elastic wave packet into the optical beam; the second, by the process of propagation of the elastic wave packet in the aperture of the optical beam; and the third, by the process of the exit of the elastic wave packet from the aperture of the optical beam. The corresponding equations for calculating the parameters of the pulse at the output of the AODL are obtained. It is shown that for a sufficiently short input pulse duration, the parameters of the output signal contain information on the energy-geometric characteristics of the laser radiation. The established provisions and patterns are confirmed by the numerical calculations. The numerical simulation results are tested on the AODL prototype with direct detection. A comparative analysis of the results of the theoretical and experimental studies show that AODL can also be used at frequencies above the boundary, both in terms of its main functional purpose and for solving a number of other radio engineering problems.

中文翻译：

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截止频率外的声光延迟线的功能

摘要

声光延迟线 (AODL) 是时域信号处理的有效工具。在很宽的时间间隔内平滑控制的信号延迟允许基于 AODL 构建高性能雷达模拟器。本文考虑了 AODL 的设计，并标记了决定使用其功能的限制的参数。针对输入脉冲的持续时间短于弹性波包穿过光束的时间的情况，研究了AODL中光弹性相互作用的特征。发现在这些条件下，输出响应的持续时间由弹性波包穿过光束所花费的时间决定，而不取决于输入动作的持续时间。结果表明，AODL 对矩形脉冲形式的输入动作的响应被确定为三项之和。在这种情况下，第一项由弹性波包进入光束的过程决定；第二，通过弹性波包在光束孔径中的传播过程；第三，通过弹性波包从光束孔径出射的过程。获得了用于计算 AODL 输出端脉冲参数的相应方程。结果表明，对于足够短的输入脉冲持续时间，输出信号的参数包含有关激光辐射能量-几何特性的信息。既定的规定和模式通过数值计算得到确认。数值模拟结果在带有直接检测的 AODL 原型上进行了测试。对理论和实验研究结果的比较分析表明，就其主要功能目的和解决许多其他无线电工程问题而言，AODL 也可用于边界以上的频率。