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:
Oct. 28, 1980
Filed:
Jan. 29, 1979
Robert L Hartman, Warren Township, Somerset County, NJ (US);
Marc Ilegems, Renens, CH;
Louis A Koszi, Scotch Plains, NJ (US);
Wilfried R Wagner, Chatham, NJ (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
A buried double heterostructure laser device isdescribed. A wafer of double heterostructure material is formed into narrow mesa stripes. A native oxide coating is formed on the side walls of the mesa. Semiconductor material having an index of refraction which is closely matched to the index of the active region is deposited over the mesa structure. High resistivity polycrystalline material forms on the native oxide and monocrystalline material forms on the top of the mesa. Vertical carrier and optical confinement is achieved by the higher bandgap cladding layers of the double heterostructure configuration. The native oxide acts as an electrical insulator to confine pumping current to the mesa. The closely matched polycrystalline material confines light parallel to the junction plane and prevents excitation of higher order transverse modes. Devices have been fabricated which exhibit cw threshold currents at room temperature as low as 55 mA.