Edge-emitting microlasers with one active layer of quantum dots

High performance edge-emitting microlasers with deeply etched distributed Bragg reflectors (DBRs) were fabricated on an AlGaAs-GaAs laser structure with a single GaInAs quantum dot (QD) active layer. Mirror reflectivities well above 90% were achieved by third-order narrow air-gap Bragg reflectors with λ/4 air-gaps. DBR lasers with 160-μm-long cavities and cleaved mirrors on one side show differential efficiencies of 0.87 W/A and output powers of more than 50 mW at 980-nm emission wavelength in continuous wave (CW) operation at room temperature. With deeply etched DBRs on both sides of the cavity CW operating microlasers with cavity lengths down to 16 μm could be realized with a minimum threshold current of 1.2 mA for a 30-μm cavity length. All lasers are emitting at the QD ground state at room temperature. Twenty-μm-long devices show CW threshold currents of about 3 mA, output powers above 1 mW, and single mode emission with >25 dB sidemode suppression ratios. First, high-frequency measurements mere performed proving that these QD microlasers are well suited for large-scale integrated high-speed optical data processing with modulation frequencies well above 10 GHz