Very low threshold current density operation of1.5 µm DFB lasers with wire-like active regions

Very low threshold 1.5 µm-wavelength GaInAsP/InP distributed feedback lasers consisting of deeply etched double quantum-well wire-like active regions have been successfully realised by CH4/H2 reactive ion etching and metal organic vapour phase epitaxial regrowth. A threshold current density Jth of as low as 94 A/cm2 was achieved for an active region width of 115 nm and cavity length of 600 µm.