A interferometric optical gyroscope includes an active resonator comprising a half cavity vertical cavity surface emitting laser (half-VCSEL) operating as one of the mirrors that form the ring resonator. The half-VCSEL includes a bottom mirror stack and active layers formed on the bottom mirror stack and has a surface opposite the bottom mirror stack. Lack of a top mirror stack typically found in a VCSEL prevents the half-VCSEL from lasing, thus the half-VCSEL forms a reflective amplifier for the light circulating in the resonator. A single or multiple external light sources can be used to induce two counterpropagating beams in the resonator. Higher finesse due to the internal gain in the resonator enhances the sensitivity of the gyroscope.