Using optical switches and fiber delay lines for wideband beamforming with RF uniform linear antenna arrays

Abstract

We investigate the use of optical switches and fiber delay lines to provide true time delays for ultra-wideband beamforming with RF uniform linear antenna arrays. In our approach, we use the received RF signals to amplitude modulate lasers of distinct wavelengths, pass the optical signals through optical switches and fiber delay lines, and combine the delayed signals before detection. Since it is impossible to provide fiber delay lines at all lengths, we investigate how to quantize delay values subject to the constraint on the inefficiency inflicted on the user power. In addition, we construct an efficient architecture for a delay line switching network that uses the minimum number of switch ports to provide the delays for beamforming.