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:
Sep. 07, 2004
Filed:
Jan. 23, 2002
Jon Thomas Kringlebotn, Trondheim, NO;
Optoplan AS, Trondheim, NO;
Abstract
A method for measurements of the orthogonally polarized minimum and maximum Bragg wavelengths of one of several birefringent fiber Bragg grate FBG sensors, and alternatively a method for eliminating errors in FBG sensor measurements caused by undesired grating birefringence, using an FBG wavelength interrogation apparatus, where the light from a polarized wavelength swept narrowband source ( ) is passed through an electrically controllable polarization controller ( ), operated in either a scanning mode or a tracking mode to find the two orthogonally polarized reflection spectra of the birefringent FBGs ( ) with corresponding minimum and maximum Bragg wavelength &ggr; and &ggr; , where a low-birefringent reference FBG with known wavelength ( ) and a low-birefringent fixed Fabry-Perod interferometer ( ), generating frequency equidistant peaks are used in combination to provide accurate and readable wavelength measurements.