Semiconductor ridge waveguide laser with asymmetrical cladding

Abstract

A semiconductor ridge waveguide laser having a high value of horizontal far-field wherein the laser structure includes a substrate, a first or lower cladding layer composed of a AlGaAs on the substrate, an acting layer on the lower cladding layer, and a second or upper cladding layer composed of AlGaAs on the active layer. The upper cladding layer includes a raised ridge portion formed by etching the upper cladding layer through a mask. A contact layer is disposed on top of the ridge portion. The aluminum mole concentration of the lower cladding layer is greater than the aluminum mole concentration of the upper cladding layer. This forces the optical mode towards the upper cladding layer and results in an increased lateral waveguide confinement that produces a high horizontal far-field.