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:
Apr. 13, 1993
Filed:
Dec. 02, 1991
Per O Granestrand, Tyreso, SE;
Telefonaktiebolaget L M Ericsson, Stockholm, SE;
Abstract
Polarization independent switch or coupler including a directional coupler with extremely relaxed fabrication tolerances. The coupler includes a mono-crystalline wafer of electro-optic material with two closely adjacent light waveguides at an upper surface along with electrodes positioned adjacent the waveguides. The electrodes include a grounded, main electrode formed on one side of the waveguides and four smaller electrodes formed in a line on a side or sides of the waveguides opposite to the main electrode, each of the four smaller electrodes being supplied with a voltage. The electrodes and waveguides can be in a planar or stacked relationship to one another. When the voltages applied to the middle two electrodes have equal values and have like polarity (V.sub.c =V.sub.b) and the voltages applied to the outer electrodes have equal values and like polarity (V.sub.d =V.sub.a), the light travelling in one waveguide is barred from transferring to another waveguide.