Tunable Self-Pulsations in a Quantum-Dot External-Cavity Laser Emitting across the Excited State

Self-pulsations have previously been observed in single-section quantum-dot (QD) lasers at low MHz frequencies
¹
and higher GHz frequencies
²
. In this contribution, we present the first demonstration of SP involving laser emission solely in the excited-state transition. This was achieved with a single-section amplifier at the core of the laser, thus in the absence of a separate saturable absorber section. SPs had a frequency of ~3.8 GHz, tunable via current variation. The use of an external cavity and the tunability afforded by this setup also allowed spectrally tunable SPs between 1160 and 1196 nm, which enabled further investigation of its dynamics (including bistability).