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:
Nov. 09, 1999
Filed:
Jul. 25, 1997
Nong Chen, Tsurugashima, JP;
Yoshiaki Watanabe, Tsurugashima, JP;
Koyoshi Takei, Tsurugashima, JP;
Kiyofumi Chikuma, Tsurugashima, JP;
Abstract
There is provided a method of manufacturing a DFB semiconductor laser in which a laser substrate having a cladding layer which is a material for a ridge stripe stacked on an active is formed. The cladding layer as a material for a ridge stripe is etched to form a ridge stripe having flat portions on both sides thereof and a flat top portion protruding therefrom. A protective film and a resist layer are formed to cover the flat portions on both sides and the flat upper surface. A latent image of a grating having a periodic structure is formed in the direction in which the ridge stripe extends is formed on the resist layer. The resist layer is developed and the flat portions on both sides are etched to form a grating on both lateral portions and to remove the protective film. An electrode is formed on the flat top portion, the interface between the ridge strip and the electrode being a smooth surface.