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:
Oct. 15, 1996
Filed:
Jun. 07, 1995
Gary A Ball, Simsbury, CT (US);
Gerald Meltz, Avon, CT (US);
United Technologies Corporation, Hartford, CT (US);
Abstract
A birefringent active fiber laser sensor includes one or more fiber lasers 12, 14, 16, each having a pair of Bragg gratings 18, 20, embedded in a fiber 10 and excited by a common pump light 30. At least one of the lasers 12, 14, 16 has a laser cavity wit a predetermined birefrigence and a lasing light at a first lasing frequency along a first polarization axis, and at a second fusing frequency along a second polarization axis. A difference frequency between the first and the second lasing frequencies is related to the magnitude of the birefringence, and the birefringence varies in response to a perturbation. Output light 104 from each of the lasers 12,14,16 is fed to a defraction grating 106 which splits the beam 104 into different wavelength groups, each group having the two lasing frequencies and polarizations of a given laser. Each wavelength group is fed to a corresponding analyzer 122-126 which combines the first and second frequencies and polarizations for each laser to form a lower difference or 'beat' frequency, thereby allowing lower frequency detection devices 138-142 to be used.