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:
Jul. 22, 2003
Filed:
Jun. 25, 2001
Klaus Bohnert, Oberrohrdorf, CH;
Hubert Brändle, Oberengstringen, CH;
ABB Research Ltd, Zurich, CH;
Abstract
The present invention relates to a fiber laser pressure sensor which is suitable in particular for measuring differential pressures and flow velocities v in oil boreholes. The fiber laser according to the invention comprises two sensor fiber segments subjected to different pressure loading, in which segments a birefringence proportional to the differential pressure &Dgr;p=p −p , and consequently a beat frequency, is induced between the polarization modes or spatial modes in the fiber laser . Exemplary embodiments with polarimetric monomode fibers and/or with elliptical two-mode fibers are specified. Furthermore, pressure-resistant multichamber sensor housings and wavelength division multiplex arrangements are disclosed for the fiber laser pressure sensor . One advantage is that the pressure signal is wavelength-coded and thus highly insensitive to interference. It can be read out directly fiber-optically over large distances between the passively optical sensor head and the optoelectronic measuring device . One application concerns the measurement of a flow velocity v with the aid of a Venturi tube