Asymmetric cladding-ridge waveguide laser by selective-area MOCVD

Ridge waveguide lasers with a thin upper cladding layer are fabricated with a two-step selective-area MOCVD growth. The lower cladding, active region, and upper cladding are all grown in the initial MOCVD growth. A second growth over an oxide pattern is used to define the ridge with 0.15 μm of GaAs, which serves as both the contact and index increasing layer. Ridge lasers fabricated by this method (3×425 μm) have a cw threshold current of 12.6 mA, slope efficiency of 0.26 W/A, and operate in a fundamental transverse mode as well as stable fundamental lateral mode to 20 times threshold.