Microwave system

A microwave system having a photonically controlled phased-array antenna comprising:

• optical signal generator means for generating first and second phase-locked, perpendicularly polarized light signals;
• a monolithically integrated signal processor means for splitting said light signals into a plurality of channels and for shifting the relative phase of said light signals in said channels, connected to said optical signal generator means;
• microwave signal means connected to said channels of said signal processor means for converting said light signals into microwave signals and for feeding said microwave signals to said phased-array antenna;
• and
• said monolithically integrated signal processor means includes:
• a network of interconnected optical waveguide devices comprising optical beam splitters, polarization-dependent optical amplifiers and polarization-selective optical phase shifters;
• a heavily doped substrate to which said optical waveguide devices are mounted;
• gain control means for amplifying said light signals propagating through said optical amplifiers;
• phase-shift control means for controlling the relative phases of said light signals;
• multiple quantum well structures having a series of barrier and quantum well layers grown on said substrate, included in each said optical waveguide device;
• and
• a top cladding layer and a heavily doped cap layer mounted on said series of barrier and quantum well layers, with said substrate and said cap layer being doped with charge carriers of opposite polarity;
• said quantum well layers of said optical beam splitters have band-gap energies that are much greater than the energies of said light signals, while said quantum well layers of said phase shifters have band-gap energies that are greater than the energies of said light signals and said quantum well layers of said amplifiers have band-gap energies that are smaller than the energies of said light signals.