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:
Jul. 19, 2005
Filed:
Jan. 27, 2003
Haruhiko Tabuchi, Kawasaki, JP;
Haruhiko Tabuchi, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In an arrayed waveguide grating type wavelength division demultiplexer including an input waveguide, an input slab waveguide, a phase-grating waveguide array composed of a plurality of optical channel waveguides, an output slab waveguide, and a plurality of output waveguides provided in a core layer so as to form a predetermined pattern, the input slab waveguide is configured to have portions with locally varied thickness in at least the core layer or the cladding layer at the vicinity of each coupling portion of the optical channel waveguide depending on the layout of the optical channel waveguides, whereby the input slab waveguide is made to have a high refractive index region having a refractive index relatively higher than surrounding regions thereof. With this arrangement of the device, the device can be applied to a case where it is undesirable to dope materials of Ge, Ti and Ce. Moreover, with this arrangement of the device, it becomes possible to avoid deterioration with time passage and reduce polarization dependent loss, thereby to improve optical coupling loss.