Uniform linear arrays of strained-layer InGaAs-AlGaAs quantum-well ridge-waveguide diode lasers fabricated by ECR-IBAE

Uniform linear arrays of strained-layer multiple-quantum-well InGaAs-AlGaAs ridge-waveguide diode lasers have been fabricated that operate near 980 nm and have low threshold currents I/sub th/ and high differential quantum efficiencies /spl eta//sub d/. Uniformity was achieved by a combination of uniform ion-beam-assisted etching with an electron cyclotron resonance ion source and uniform organometallic vapor-phase epitaxial (OMVPE) growth. We investigated the effects of device geometry, namely, ridge width, cavity length, and remaining cladding thickness outside the ridge t, on I/sub th/ and /spl eta//sub d/. For uncoated lasers with 500-/spl mu/m-long cavities, 2- to 3-/spl mu/m-wide ridges, and t=165/spl plusmn/75 nm fabricated in double-quantum-well OMVPE material, I/sub th/ was typically in the range 6-7 mA and /spl eta//sub d/ was >40% per facet. A 24-element array of 2-/spl mu/m-wide, 200-/spl mu/m-long ridge-waveguide lasers with a high reflection coating on the back facet exhibited excellent uniformity, with threshold currents and single-ended differential quantum efficiencies that averaged 3.4 mA and 72%, respectively. Similar arrays with high-reflectivity coatings on both facets exhibited threshold currents as low as 2 mA. >