Subharmonic synchronous mode-locking of a 33 GHz monolithic semiconductor laser-subharmonic number dependence

Abstract

The characteristics of subharmonic synchronous mode-locked pulses of monolithic semiconductor lasers are dependent on subharmonic number. The subharmonic number dependence is investigated by varying the repetition frequency of the injected pulses from 25 MHz to 3.3 GHz while keeping the pulse-width and average power at nearly the same values throughout the range. A high repetition rate pulse trains are generated at 33 GHz with very low phase noise by subharmonic synchronous mode-locking at very low injection frequencies and the reduction of injection frequency will lead to significant increase in phase noise.