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:
Feb. 28, 1995
Filed:
Nov. 01, 1993
NEC Corporation, Tokyo, JP;
Abstract
A distributed-feedback laser has a diffractive grating, an optical waveguide layer, and an active region. The optical waveguide layer has equivalent refractive indexes larger towards cavity end facets and smaller towards a device center portion along a cavity. The active region containing the optical waveguide layer has widths wider towards the cavity end facets and narrower towards the device center portion along the cavity. The optical waveguide layer has a uniform electric intensity distribution along the cavity to improve the linearity of current versus optical output characteristics. In another arrangement, the optical waveguide layer formed on the diffractive grating has in its compositions longer wavelengths towards the cavity end facets and shorter wavelengths towards the cavity center portion along the cavity, whereby the optical waveguide layer has a uniform optical intensity distribution along the cavity to improve the linearity of current versus optical output characteristics. The distributed-feedback laser provided is with improved analog modulation distortion characteristics.