Abstract

It has been shown that guided-wave planar acoustooptic (AO) beam deflectors of large bandwidth and high diffraction efficiency can be realized in LiNbO₃ substrates, ^(1,2) and that such AO beam deflectors are suited for a number of applications in wideband optical communications and information processing. ⁽³⁾ In fact, some encouraging results have already been demonstrated in the experiments involving spectrum analysis^(3,4) and convolution of wideband rf signals⁽⁵⁾ as well as deflection/switching of a light beam at moderate-speed.⁽³⁾ In this paper we report research progress on further utilization of such AO beam deflectors for optical pulse compression and very high-speed light beam scanning. In order to carry out a number of additional studies including a more detailed experiment on spectrum analysis and the two new experiments just mentioned, we have recently fabricated a very wideband deflector in a Y-cut LiNbO₃ Ti-diffused waveguide. This deflector employs a three-element tilted-array transducer with the center frequencies of 275, 432 and 648 MHz, and has a measured deflector bandwidth of 500 MHz. This bandwidth represents the largest that has been achieved thus far. Using the AO Bragg diffraction of a He-Ne laser guided-light beam from the surface acoustic waves generated by a linear FM rf (chirp) waveform, we have achieved a compression ratio of 200 in the optical pulse compression experiment and a scanning rate of 125 x 10⁶ spots/sec for 50 spots in the beam scanning experiment. The detailed results of these two experiments will be reported. We will discuss means for further utilization of this wide­band deflector to obtain a much larger compression ratio and a much higher scanning rate. We will also discuss some potential applications of the resulting devices in wideband optical communications and data processing.

© 1978 Optical Society of America