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:
Jun. 04, 2002
Filed:
Jul. 20, 1998
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical device has a substrate, a polarization beam splitter, first and second pairs of optical waveguides, a transducer and a thin film. The polarization beam splitter is formed on the substrate and has input and output sides. The first and second pairs of optical waveguides are formed on the substrate to guide polarized optical signals. The first pair of optical waveguides meets at the input side of the polarization beam splitter, and the second pair of optical waveguides meets at the output side of the polarization beam splitter. The transducer is formed of a comb-tooth electrode on the substrate to excite a surface acoustic wave on the substrate and rotate the polarization of the optical signal. The thin film covers a portion of each waveguide of either the first or second pairs of optical waveguides. The thin film may be formed of silicon dioxide or indium dioxide, either with a metal oxide optionally added thereto. The speed of sound in the thin film is less than that in the substrate. The thin film is formed of a material which is transparent to the optical signal. The thin film has a refractive index smaller than that of the optical waveguides.