Extreme pulses in gain-switched semiconductor lasers

Semiconductor lasers subjected to strong current modulation produce gain-switched optical pulse trains. These lasers can also produce pulse trains at sub-harmonic repetition rates relative to the driving current modulation. We experimentally observe, and numerically model, that these pulse trains can be interrupted by single-cycle extreme pulses whose characteristics and statistics are similar to rogue waves. Modeling indicates that drops in the circulating optical power in the optical cavity precede the appearance of extreme pulses. At the single photon level, the stochastic source terms in the optical field equation dominate the circulating optical power.