Low threshold current density and high quantum efficiency 980nm CW QW laser

Theoretical and experimental investigation of 980nm quantum well ridge waveguide lasers suitable for pumping Er3+ doped fiber amplifiers are carried out. The valence hole subbands, the TE and TM mode optical gains, and the radiative current density of the In0.2Ga0.8As/GaAs/GaAs strained quantum well (70 Angstrom well width) lasing at 980nm have been investigated using a 6x6 Hamiltonian model. A very low threshold current density is predicted. These theoretical results would be useful for the design and further performance improvement of the ternary InGaAs and quaternary InAlGaAs strained QW laser diodes. Mesa, stripe geometry and ridge waveguide three quantum wells lasers have been fabricated from a graded index separate confinement heterostructure grown by molecular beam epitaxy. For a 4 mum wide and 1000 mum long ridge waveguide laser, a cw threshold current of 12.5mA, the threshold current density of 313A/cm(2), an external quantum efficiency of 0.31mW/mA and power slope efficiency of 0.37mW/mA per facet were obtained.