Mode competition and mode locking in compound cavity semiconductor lasers

This letter concerns the mode-competition effect for compound-cavity lasers. Considering the mode properties of such a system we show, that the side cavity mode having the same threshold gain as the lasing one, may correspond to either stable or unstable modes of laser operation. In the last case the mode competition leads to locking of the lasing and side modes yielding high-frequency self-pulsations in some range of the system parameters. This effect can be used for the design of self-pulsating SLs generating optical pulses in the microwave region without an intracavity saturable absorber.<>