A method and structure for producing lasers having good optical wavefront
characteristics, such as are needed for optical storage includes
providing a laser wherein an output beam emerging from the laser front
facet is essentially unobstructed by the edges of the semiconductor chip
in order to prevent detrimental beam distortions. The semiconductor laser
structure is epitaxially grown on a substrate with at least a lower
cladding layer, an active layer, an upper cladding layer, and a contact
layer. Dry etching through a lithographically defined mask produces a
laser mesa of length l.sub.c and width b.sub.m. Another sequence of
lithography and etching is used to form a ridge structure with width w on
top of the mesa. The etching step also forming mirrors, or facets, on the
ends of the laser waveguide structures. The length l.sub.s and width
b.sub.s of the chip can be selected as convenient values equal to or
longer than the waveguide length l.sub.c and mesa width b.sub.m,
respectively. The waveguide length and width are selected so that for a
given defect density D, the yield Y.sub.D is larger than 50%.