| 摘要 |
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 </SUB>and width b<SUB>m</SUB>. 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 </SUB>and width b<SUB>s </SUB>of the chip can be selected as convenient values equal to or longer than the waveguide length l<SUB>c </SUB>and mesa width b<SUB>m</SUB>, respectively. The waveguide length and width are selected so that for a given defect density D, the yield Y<SUB>D </SUB>is larger than 50%.
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