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:
Aug. 13, 2002
Filed:
Aug. 02, 2000
William K. Bischel, Menlo Park, CA (US);
Tony C. Kowalczyk, Palo Alto, CA (US);
Gemfire Corporation, Palo Alto, CA (US);
Abstract
A device for variable attenuation of an optical channel includes an elongated core surrounded by a cladding. Optical energy propagating along the longitudinal axis of the core is normally confined thereto by the difference in refractive indices between the core and cladding. The thermo-optic coefficients of the core and cladding are closely matched such that waveguide confinement is substantially invariant with respect to ambient temperature. The device further includes a thermal source arranged above the core. The thermal source is operable to generate a temperature gradient of controllable magnitude along a vertical axis extending through the core. The temperature gradient causes reduction of the local refractive index within the core relative to surrounding regions of the cladding such that a portion of the optical energy is deflected away from the thermal source and extracted from the core.