The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 30, 1994
Filed:
Oct. 01, 1992
Jeffery W Scott, Carpinteria, CA (US);
Larry A Coldren, Santa Barbara, CA (US);
Optical Concepts, Inc., Lompac, CA (US);
Abstract
In a vertical-cavity surface-emitting laser (VCSEL) with an active region, and first and second mirror stacks forming a resonant cavity, the VCSEL having a radial electrode configuration with a first electrode disposed around the base of the first mirror stack near one side of the active region, a second electrode on the other side of the active region with a first contacting region and a second contacting region on each side of the active region in contact with the respective electrodes, each of the contacting regions providing a current path for distributed current through the active region, the improvement wherein there is a nonlinear grading of resistivity in at least one of the contacting regions between at least one of the electrodes and the active region. Specifically, in one embodiment, the first contacting region has a first layered section abutting the first electrode which is highly conductive to radial current flow and at least a second layered section between the first layered section and the active region which is more resistive to axial current flow than to radial current flow in the first layered section. In a further embodiment, one of the two contacting regions includes a layered section which is radially graded in resistivity so as to restrict the current injection to a radius less than that of the resonant cavity, thereby improving device efficiency and preferentially supporting single mode operation.