Intensity noise behavior of an InAs/InGaAs quantum dot laser emitting on ground states and excited states

We experimentally and numerically study the amplitude stability of an InAs/InGaAs quantum dot laser emitting simultaneously on ground states (GSs) and excited state (ESs) at center wavelengths of 1245 and 1168 nm, respectively. The stability is quantified by a spectrally resolved noise current analysis that is dependent on the laser injection current. We find a non-monotonic behavior of the amplitude noise which shows a reduction of up to 4 dB when the GS and ES emit simultaneously. Simulations based on a rate equation model confirm the reduction in noise and suggest the cascaded GS and ES carrier paths as the relevant underlying mechanism.