An original design of ring semiconductor lasers based on InAs/InGaAs/GaAs quantum dots, promising for clock pulse generation, optical sensing, biological and medical applications, and microwave photonics, has been proposed and tested. Lasing was obtained at room temperature with a nominal threshold current density as low as 150 A cm−2. The output power in continuous wave mode was 45 mW.

We present an experimental study of the optical gain of edge-emitting lasers based on a new type of quantum-sized InGaAs active medium grown on GaAs substrates, which we refer to as quantum-well-dots (QWDs). It is shown that the single layer QWD active region provide at least 33 cm−1 optical gain at 1030 nm comparable to the values typical for InGaAs quantum wells (QWs), and the width of the gain spectra characteristic for InAs quantum dots (QDs). Thus, QWD active region combines the advantages of both QW and QD heterostructures and has a great potential for improving characteristics of various semiconductor devices.

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We present a study of characteristics of the edge-emitting lasers operating in the 0.98 μm wavelength range and based on a new type of InGaAs/GaAs active region – quantum well-dots (QWD). Utilizing the QWD active region in broadened 1.3 μm waveguide (BWG) allowed us to decrease the internal loss down to 0.5 cm−1 and to demonstrate the maximum output power of 13W and 50W in continuous wave (CW) and pulse operation regimes respectively. The investigation of the lasing spectra under high pulse injection currents revealed the overheating of the active region in the devices with moderate waveguide thickness (0.68 μm) in contrast with BWG devices.