InAs/GaAsSb in-plane ultrahigh-density quantum dot lasers

InAs in-plane ultrahigh-density quantum dots (IP-UHD QDs) were grown on GaAsSb/GaAs(001) by molecular beam epitaxy and were introduced into the active layer of a ridge-waveguide AlGaAs/GaAs laser. The IP-UHD QD density was 5 ×1011 cm-2. Despite of short cavity length, no high-reflective coating on cavity edge and small number of stacked QD layers, stable laser operation up to 80 ℃ has been achieved. IP-UHD QD lasers without p-type doping exhibited a characteristics temperature of 77 K. IP-UHD QD lasers had the same low internal loss as conventional QD lasers. Improved uniformity in IP-UHD QDs promises to achieve ultralow threshold current.