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:
May. 04, 1993
Filed:
Dec. 12, 1991
Won-Tien Tsang, Holmdel, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
DFB lasers with advantageously structured grating region are disclosed. The grating region comprises one or more thin semiconductor layers (to be referred to as 'QWs'), with the QWs varying periodically in the longitudinal direction of the laser. In an exemplary preferred embodiment the AWs are patterned during grating etch, with the topmost grating QW being covered with a layer of substantially the substrate composition. The structure inter alia facilitates defect-free epitaxial growth on the corrugated etched surface and also facilitates growth of the coupling coefficient .kappa.. Furthermore, lasers according to the invention can be partially or purely gain coupled, resulting in desirable wavelength discrimination.