Abstract

One-dimensional, serial data streams can be visualized and processed by mapping the "time" variable into appropriate spatial coordinates. Delay lines are convenient tools that are often used to achieve such operations. Optical time delays in a range of up to microseconds can be easily generated by propagating optical waves in free space or waveguides. However, long propagation delays on the order of, say, seconds, are inconvenient to obtain. Here we present an optical time delay line that uses holographic beam coupling in a rotating photorefractive crystal. It is a true time delay line in the sense that the delayed signal retains the frequency and phase of the original signal.

© 1993 Optical Society of America