New self-align method for fabrication of 980 nm ridge waveguide laser diodes

A novel self-align method has been developed for the fabrication of 980 nm ridge waveguide laser diodes. It utilizes the facts that (1) the thickness of photoresist on the ridge top is substantially less than that in its vicinity and (2) their respective exposure times differ accordingly. Except for replacing the second photolithographic step with a simple flood-exposure, the fabrication procedure is identical to that for conventional ridge waveguide laser diodes. No additional materials or processing steps are required. As a result, the laser fabrication is significantly simplified with excellent reproducibility.