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. 30, 1999
Filed:
May. 01, 1998
Hideaki Arai, Ibaraki, JP;
Ryoji Suzuki, Ibaraki, JP;
Korenori Tamura, Ibaraki, JP;
Hisato Uetsuka, Ibaraki, JP;
Hitachi Cable, Ltd., Tokyo, JP;
Abstract
A waveguide type grating device according to the invention includes a quartz substrate, a cladding and two waveguides. Waveguides are arranged to provide an input port, an Add port, an output port, a Drop port, directional 3 dB couplers, core width-changing portions, and grating portions each interposed between core width-changing portions. The width of core is changed between each non-grating portion and each grating portion in an adiabatic structure, for example, a parabolic structure. For this structure, a waveguide type grating device is structured to suppress the increase in wavelength loss due to coupling from progressive propagation mode to regressive radiation mode, with less cost and smaller dimension.