True time delay line for short pulses based on optical path-length dispersion: experimental proof of functioning

A true time optical delay line for short pulses by means of acousto-optic signal processing is presented. A theoretical description of the heterodyning delay line based on spatial Fourier decomposition and differential optical phase shift of the pulse frequency components is given. 2 μs time delay of 0.5 μs long pulses with maximum optical phase shift of 1.2 π was experimentally realised. Implementation of the delay line for an array with more than 10000 antenna elements, for more than 50% fractional bandwidth is theoretically examined, and a compact optical system with two-dimensional acousto-optic deflector and LCD SLM is proposed