Room Temperature Optically Pumped 2.56- $\mu{\rm m}$ Lasers With “W” Type InGaAs/GaAsSb Quantum Wells on InP Substrates

The optically pumped laser using InGaAs/GaAsSb W-type quantum wells is demonstrated with a threshold power density ~ 40 kW/cm
²
. The L-L curve and the dramatic line width shrinkage above threshold confirm, for the first time, mid-infrared lasing in this structure on InP substrates. The lasing wavelength at 2.56 μm is the longest lasing wavelength at room temperature for the interband transition of InP-based material system.