Gain spectra analysis of bilayer quantum dot lasers beyond 1.3μm

In this paper we report on the analysis of molecular beam epitaxy (MBE) grown GaAs and InGaAs capping bilayer QD laser material via a number of characterization techniques. The InGaAs capped bilayer QD lasers extends the room temperature lasing wavelength to 1.45μm. The further analysis of the materials using the multi-section technique allows the gain and absorption spectrum to be obtained under various CW and pulsed bias conditions and at a range of currents and temperatures. The spectral measurement of gain demonstrates that net modal gain is achieved beyond 1.5μm at room temperature. Analysis of the temperature and current density dependence of gain allows insight into the increase in threshold current around room temperature for a GaAs capped bilayer laser.