Broad-area diode lasers with plane-mirror and phase-conjugate feedback

The output state of a broad-area diode (BAD) laser with phase conjugate feedback (PCF) from Rh:BaTiO/sub 3/ crystal is compared to the same diode laser with conventional optical feedback from a plane mirror. A number of distinct output states, including low frequency fluctuations, are observed for each feedback type. Stable single spectral mode output is achieved with phase conjugate feedback above an injection current dependent critical level (/spl sim/20%). Conventional optical feedback from a plane mirror does not induce single-mode output at any feedback level.