Electrical-optical characteristics of buried waveguide heterostructure InGaAsP injection lasers

The fabrication procedure, electrical properties, and optical characteristics of InGaAsP buried-waveguide-heterostructure (BWH) lasers emitting at γ = 1.3 µm are described and compared with InGaAsP buried heterostructure (BH) and strip-buried heterostructure (SBH) lasers. Threshold currents as low as 140 mA have been achieved for the BWH structure which incorporates a high band gap quaternary waveguide layer adjacent to the active layer stripe. Measurements of the variation of the near-field and far-field patterns with stripe width indicate that the BWH device will operate in the fundamental transverse mode for stripe widths up to 5 µm.