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:
Aug. 12, 1997
Filed:
Jun. 23, 1995
Robert J Lang, Pleasanton, CA (US);
Julian S Osinski, Palo Alto, CA (US);
David F Welch, Menlo Park, CA (US);
SDL, Inc., San Jose, CA (US);
Abstract
A semiconductor light amplifying medium has reduced self-focusing and optical filamentation for providing higher power coherent outputs in broad-area laser and amplifier devices. In one embodiment, a longitudinally inhomogeneous active region has alternating segments of first gain portions and second compensating portions. The compensating portions have a negative self-focusing parameter [.differential.n/.differential.P] and may be light absorbing (negative gain) regions with negative antiguiding factor .alpha. or light amplifying (positive gain) regions with positive antiguiding factor .alpha.. The .alpha.-parameter is defined as the ratio of refractive index change per change in gain, as a function of carrier density. In a second embodiment, the medium may have longitudinally varying peak filament period so that filaments beginning to form in one portion of the active region are subsequently dispersed in a succeeding portion, slowing filament growth. In addition to self-focusing compensation, media with a lower .alpha.-parameter are provided by increasing the barrier height in quantum well active regions, straining or p-doping the active region, or a combination of these methods.