Abstract: Passive ring resonator laser gyro in which the clockwise and counterclockwise beams do not coexist in the resonator. The laser gyro employs thin film technology. In particular, the preferred laser is a gallium aluminum arsenide laser. Light from the laser is phase-modulated by means of a thin film electro-optic modulator comprising a channel waveguide disposed on an electrically active material and flanked by electrodes for modulating the phase of light from the laser. An electro-optic switch is provided for switching light from the laser to inject alternatingly clockwise and counterclockwise beams into the resonator. The resulting gyro is extremely compact and simply implemented into an integrated, thin film package. Because the clockwise and counterclockwise beams do not coexist in the resonator, various beam interaction effects such as beats, backscatter and feedback into the laser are eliminated.