Photonic mm-wave local oscillator

A millimeter wave source derived from a phase modulated optical signal has been developed. The spectral purity and phase control of the phase of the source allowed it to be used as a local oscillator with an astronomical millimeter wave interferometric array. The phase and amplitude stability of the correlated signals of the array are comparable to that produced by Gunn based local oscillators. The system is explained in the following article first as a simple open loop system and then as a more complex closed loop device where the phase is controlled. A mathematical description is given which predicts system behavior. The telescope correlator output graphs show phase and amplitude stability.