Low threshold highly efficient strained quantum well lasers at 1.5 micrometre wavelength

Low threshold and high efficiency operation of strained layer multiple quantum well InGaAs/InGaAsP lasers at 1.5 micrometres wavelength is demonstrated. Current thresholds as low as 2.2 mA with threshold current densities of 440 A/cm2 have been obtained. With 7.3 mA threshold current, quantum efficiency was 65%/front facet. At 20 mW CW output power the drive current was as low as 53 mA.