Frequency modulated phase-locked stabilized passive ring laser gyro

摘要

A passive ring resonator gyroscope having an integral single piece body having first and second resonator cavities. A laser uses the first resonator cavity. The laser has a first cavity adjusting means (PZT1) responsive to a first control signal for providing a single frequency light source (F0). The second resonator cavity is a passive high Q evacuated cavity having a closed optical path tuned to resonate at substantially the light frequency of the first resonator cavity. A modulating means modulates the single frequency light source to form a frequency modulated light source having a center frequency equal to the single frequency light source (F0) and having upper and lower side bands at frequencies Fo+Fm and at F0-Fm, respectively. The frequency modulated light source is split into respective first and second frequency modulated rays. The first ray center frequency is shifted by a fixed offset frequency (F1) to form a propagating light beam (FCW) in the second resonator cavity. The second frequency modulated ray forms a counterpropagating light beam in the second resonator cavity. A cavity servo maintains the propagating light beam (FCW) in the second resonator at peak resonance and frequency shifts the second frequency modulated ray by a variable offset frequency (F2) to maintain the counterpropagating light beam (FCCW) at peak resonance.