Injection locking characteristics of semiconductor lasers in double phase conjugate mirror geometry

Phase locking of two semiconductor lasers is demonstrated by injection of the feedback from a double phase conjugate mirror. The stability or quality of the locking is characterised from fringe visibility measurements. Phase conjugate injection into the central mode exhibits an asymmetric stable locking region which extends to greater detunings and asymmetry with increased feedback. High quality locking is also demonstrated by phase conjugate injection into sidemodes up to nine longitudinal mode spacings from the target mode.