Subharmonic synchronous modelocking of an external cavity semiconductor laser

In this paper, we propose a novel signal generation technique whereby stable pulsed operation of a semiconductor laser (without saturable absorber) is realised by injecting optical pulses at a subharmonic of the cavity frequency, and demonstrate the technique using an external cavity laser. This technique is very desirable since it can be used to obtain pulsed operation from Fabry-Perot semiconductor lasers with repetition rates beyond 50 GHz.