Very low threshold current density room temperature continuous-wave lasingfrom a single-layer InAs quantum-dot laser

Continuous-wave (CW) lasing operation with a very low threshold current den sity (J(th) 32.5 A/cm(2)) has been achieved at room temperature by a ridge waveguide quantum-dot (QD) laser containing a single InAs QD layer embedded within a strained InGaAs quantum well (dot-in-well, or DWELL structure). L asing proceeds via the QD ground state,vith an emission wavelength of 1.25 mu m when the cavity length is longer than 4.2 mm, For a 5-mm long QD laser , CW lasing has been achieved at temperatures as high as 40 degrees C, with a characteristic temperature T-0 of 41 K near room temperature. Lasers wit h a 20 mu m stripe width have a differential slope efficiency of 32% and pe ak output power of >10 mW per facet (uncoated).