980 nm InGaAs/AlGaAs quantum well lasers with extremely low beam divergence

Abstract

We report on the fabrication of 980 nm InGaAs-AlGaAs lasers with a specially designed cladding structure. For a 2.5 /spl mu/m wide ridge waveguide structure, the far field pattern has a vertical divergence of only 13/spl deg/ and a lateral divergence of 8/spl deg/. Meanwhile, the threshold current can remain acceptably low. In addition, with another design, a record small vertical far field angle of 11/spl deg/ was obtained.