Theory of a diode laser with phase-conjugate feedback.

A single-mode diode laser subject to reflections from an externally pumped phase-conjugate mirror is theoretically investigated by using a rate-equation approach. In the phase plane defined by the amount of feedback and the frequency detuning between diode laser and phase-conjugate mirror, we found an island of locked steadystate behavior, surrounded by another type of steady-state behavior, referred to as the frequency-difference solution, and a region of self-pulsating relaxation oscillations.