| 摘要 |
<p>A method and structure for producing lasers (10) having good optical wavefront characteristics, such as are needed for optical storage includes providing a laser (14) wherein an output beam emerging from the laser front facet (16) is essentially unobstructed by the edges of the semiconductor chip (12) m order to prevent detrimental beam distortions The semiconductor laser structure (14) is epitaxially grown on a substrate (12) with at least a lower cladding layer (20), an active layer (22), an upper cladding layer (24), and a contact layer (26) Dry etching through a lithographically defined mask produces a laser mesa (14) of length lc and width bm Another sequence of lithography and etching is used to form a ndge structure (32) with width w on top of the mesa (14) The etching step also forming mirrors, or facets (16, 18), on the ends of the laser waveguide structures (32) The length I5 and width bs of the chip (12) can be selected as convenient values equal to or longer than the waveguide length lc and mesa width bm respectively The waveguide length and width are selected so that for a given defect density D, the yield YD is larger than 50 %</p> |
