Switched three dimensional photonic delay line using directly modulated semiconductor lasers for microwave radar processing

A 3-bit binary photonic delay line is demonstrated at 1 GHz using a directly modulated semiconductor laser and remote interconnection fiber-optics. Three types of freespace delay bit geometries are tested for 5.686 ns, 1.667 ns, and 8.83 ps delay bits. This photonic delay line uses ferroelectric liquid crystal optical on/off devices for optical path switching and active polarization noise filtering. 3D imaging optics and antireflection coated optics are successfully used to minimize photonic delay line insertion losses and interchannel crosstalk. The 3-bit system is fully characterized for measured and designed performance