University of California

Optical Concepts, Inc.

Jeffery W Scott

Larry Allen Coldren

Ran H Yan

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.

Electrical pumping scheme for vertical-cavity surface-emitting lasers

A surface-normal cavity, AlGaAs, Distributed-Bragg Reflector laser. The laser is constructed on a GaAs substrate. There is a nipinipi . . . gain-producing active section comprised of a plurality of gain-producing i-segments disposed at periodic intervals with respect to the wavelength of an intended operating frequency of the laser is stacked vertically with respect to the surface of the substrate. A pair of Distributed-Bragg-Reflector stacks are disposed at the respective ends of the nipinipi . . . active section. A pair of electrodes are formed on either side of and operably connected to the nipinipi . . . active section in electrical contact therewith for applying a driving current to the nipinipi . . . active section in parallel. In one embodiment, the nipinipi . . . active section has interfaces between p+ and n+ sections thereof positioned at standing wave maxima of the intended operating frequency of the laser. In another, the nipinipi . . . active section has interfaces between p+ and n+ sections thereof displaced from standing wave maxima of the intended operating frequency of the laser an amount which will allow the impedance discontinuity of the active segment to result in more in-phase reflection components whereby the gain-producing active section acts as a mirror and the net effective reflectivity of the laser is increased.

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Carpinteria, CA, United States of America

Jeffery W Scott