SUBMILLIAMPERE-THRESHOLD 1.5-MU-M STRAINED-LAYER MULTIPLE QUANTUM-WELL LASERS

We have studied the effect of high-reflection facet coatings on strained-layer multiple quantum well lasers and made, for the first time, submilliampere-threshold lasers in the 1.5-mu-m wavelength region with a short cavity and high-reflection-coated facets. As a result of the compressive strain, the threshold current density is loss limited instead of transparency limited. By the use of the step graded-index separate confinement heterostructure to reduce the waveguide loss, a threshold current density of 550 A/cm2 was measured on 30-mu-m wide broad area lasers with 1-mm long cavity.