Low threshold current GaAs/AlGaAs grin-SCH lasers grown by molecular beam epitaxy on Si3N4 masked substrates

High-performance single-quantum-well graded-refractive-index separate confinement heterostructure (SQW GRIN-SCH) lasers have been grown by molecular beam epitaxy on Si3N4 patterned GaAs (100) substrates. Lasers grown on stripe windows orientated in the [011] direction have optical waveguiding and current confinement supplied by facetting occurring during growth. Lasers fabricated on 10μm wide Si3N4 openings have threshold currents as low as 15 mA for a 500 μm-long cavity. The current density required to reach optical transparency is 144 A/cm2, an internal quantum efficiency of 81%, and a peak optical power of 70 mW per facet has been obtained. Device performance comparable to ridge lasers is observed in a self-aligned laser process.