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AssigneeAT&T Bell Laboratories
InventorsDennis G. Deppe, Leonard C. Feldman, Rose F. Kopf, Erdmann F. Schubert, Li Wei Tu, George J. Zydzik
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This invention is a semiconductor vertical cavity surface emitting laser comprising a lasing cavity with an active layer, a bottom (rear) mirror and a top (front) mirror, and a front and rear electrodes for applying excitation current in direction substantially parallel to the direction of optical propagation. In accordance with this invention the front mirror comprises a thin, semitransparent metal layer which also acts as the front electrode. The metal layer is upon a highly doped layer forming a non-alloyed ohmic contact. The metal is selected from Ag and Al and is deposited in thickness ranging from 5 to 55 nm. The VCSEL is a semiconductor device wherein the semiconductor material is a III-V or II-VI compound semiconductor. For a VCSEL with GaAs active layer, the light output from the front metal mirror/electrode side yields a high external differential quantum efficiency as high as 54 percent. This is the highest quantum efficiency obtained in VCSEL structures. Quantum efficiencies on the oder of 10 to 30 percent are typical for prior art VCSEL structures. The VCSEL is suitable for fabrication utilizing planar technology.
In a semiconductor vertical cavity surface emitting laser comprising at least one semiconductor selected from GaAs, GaAlAs, GaInAs, InP, InGaPAs and other related Group III-V and Group II-VI compound semiconductor, a plurality of layers including an active region which generates optical radiation and a rear mirror which reflects said radiation,
In a semiconductor vertical cavity surface emitting laser, wherein said semiconductor comprises at least one semiconductor selected from GaAs, GaAlAs, GaInAs, InP, InGaPAs and other related group III-V and II-VI compound semiconductors, a plurality of layers comprising in an ascending order from a semiconductor substrate
In a semiconductor vertical cavity surface emitting laser, wherein said semiconductor comprises at least one semiconductor selected from GaAs, GaAlAs, GaInAs, InP, InGaPAs and other related group III-V and group II-VI compound semiconductors, a plurality of layers including an active region which generates optical radiation, a rear mirror which reflects said radiation, a front mirror which partially reflects and partially transmits said radiation in direction perpendicular to the active region, the front mirror being of a metal which forms a non-alloyed ohmic contact to the semiconductor body and serves simultaneously as a front electrode of the laser, and a rear electrode for applying in unity with the front mirror an excitation current in direction substantially perpendicular to the active region and substantially parallel to the direction of propagation of optical radiation,
Dependencies are inferred from the claim text.