5 bit photonic time shifter for wideband arrays

Abstract

A 5 bit photonic time shifter (switchable delay line) was developed for applications to wideband array antennas. This module was used to steer the beam on the subarray level, which required up to 10 ns delay in the true time delay beamforming network. The time shift module consists of four diode lasers and eight photodetectors in conjunction with fibre optic delay lines and a 4/spl times/8 optical coupler connected in between. The L-band module has a 38 dB loss at present. A silica waveguide-based delay line technology using monolithic-hybrid integration is under way. The miniaturised version will reduce the loss by combining a laser and detector switch array plus other OEIC components in the package.