Optical Noise of Dual-State Lasing Quantum Dot Lasers

Abstract

This paper theoretically investigates the optical noise characteristics of the simultaneous ground-state (GS) and excited-state (ES) lasing quantum dot lasers. The optical noise dynamics of both states are analysed through coupling the Langevin noise sources into a set of coupled rate equations. It is pointed out that the ES emission significantly changes the evolution scenario of the relative intensity noise, the frequency noise (spectral linewidth), and the linewidth broadening factor of the GS emission, as a function of the bias current. In the vicinity of the ES lasing threshold, the relative intensity noise and the frequency noise of the GS emission is lower than those of ES emission. However, the linewidth broadening factor of the GS emission is larger than the latter.