US 5,343,487 A · Electrical pumping scheme for vertical-cavity surface-emitting lasers

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.

Claims23

Dependent claims

A vertical-cavity surface emitting laser device (VCSEL), said VCSEL device having an active region, first and second mirror stacks forming a resonant cavity, a radial like electrode configuration with a first electrode disposed largely around a base of the first mirror stack near a first side of the active region, a second electrode on an opposing second side of the active region, a first contacting region and a second contacting region on each first and second side of the active region in contact with said respective first electrode and said second electrode, each one of said contacting regions providing a current path for distributed current through the active region, the improvement comprising:

a nonlinear increasing resistivity profile in at least one of said contacting regions between at least one of said first or second electrodes and said active region where said increasing resistivity is such that the resistivity adjacent to said active region is at least one order of magnitude greater that the resistivity in contact with said first or second electrode to minimize current crowding at perimeter edges of said active region.

A method for constructing a vertical-cavity surface emitting laser device (VCSEL), said VCSEL device having an active region, first and second mirror stacks forming a resonant cavity, a radial electrode configuration with a first electrode disposed around a base of the first mirror stack near one side of the active region, a second electrode on the other side of the active region, a first contacting region and a second contacting region on each side of the active region in contact with said respective first electrode and said second electrode, each one of said contacting regions providing a current path for distributed current through the active region, the method comprising:

constructing a nonlinear grading of resistivity in at least one of said contacting regions between at least one of said first or second electrodes and said active region to minimize current crowding at perimeter edges of said active region by:
a) placing a second layered section upon said active region, said second layered section being more resistive to longitudinal current flow than to radial current flow in a first layered section;
b) placing a first layered section upon said second layered section, said first layered section being highly conductive to radial current flow;
and
c) placing said one electrode in radial contact with said first layered section.

2 more elements

A vertical-cavity surface emitting laser device (VCSEL), said VCSEL device having an active region, first and second mirror stacks forming a resonant cavity, a radial like electrode configuration with a first electrode disposed around a base of the first mirror stack near a first side of the active region, a second electrode on an opposing second side of the active region, a first contacting region and a second contacting region on each first and second side of the active region in contact with said respective first electrode and said second electrode, each one of said contacting regions providing a current path for distributed current through the active region, the improvement comprising:

a nonlinear grading of resistivity in at least one of said contacting regions between at least one of said first or second electrodes and said active region to minimize current crowding at perimeter edges of said active region;
and wherein said first contacting region comprises:
a first layered section abutting said first electrode, said first layered section being highly conductive to radial current flow;
and
at least a second layered section between said first layered section and said active region, said second layered section being more resistive to longitudinal current flow than to radial current flow in said first layered section.

2 more elements

Dependencies are inferred from the claim text.

Electrical pumping scheme for vertical-cavity surface-emitting lasers

Life of this patent

Electrical pumping scheme for vertical-cavity surface-emitting lasers

Life of this patent

Abstract

Claims23