Abstract: A two source passive ring resonator gyroscope having a single piece body with integral first, second and third resonator cavities. A first laser means uses the first resonator cavity to provide a first single frequency light source. A second laser uses the second resonator for a second laser to provide a second single frequency light source. The third 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 and second resonator cavities. The first signal frequency light source is split into a propagating light source and a first reference frequency light source. The propagating source is coupled into the third resonator cavity to form a propagating light beam. The second single frequency light source is split into a second frequency light source and into a second reference frequency light source.