Intrinsic performance of InGaAs-GaAs quantum dot lasers

We have studied the properties of quantum dot lasers comprising a single layer of InGaAs dots set in a single GaAs quantum well, 100 A wide, in a waveguide core region of AlGaAs with cladding layers of AlGaAs. Measurements have been made of the quasi-Fermi level separation, optical mode loss and gain spectra as a function of temperature by a single pass technique using a device with a segmented contact and of the spontaneous emission spectra using light emerging from a narrow window in the device top contact.