Abstract: A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser means to provide a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is sharply tuned and is split to form first and second sources. The second resonator cavity is a passive high Q cavity having a closed second optical path. The two light sources are fed to the second resonator and propagate as CW and CCW beams within the second resonator. A first servo tunes the frequency of the linear laser to the resonance peak of the CW beam in the second resonator. A second servo means is provided to shift the frequency of the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis.