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:
Dec. 03, 2002
Filed:
Apr. 06, 2001
John Philip Dakin, Romsey, GB;
Stuart John Russell, Downend, GB;
University of Southhampton, , GB;
Abstract
A Sagnac or loop type interferometer is disclosed which uses a single broadband Erbium-doped fibre source ( ) and a single IngaAs detector ( ) together with a 40 km long sensor loop ( ). A wavelength division multiplexer ( ) spectrally slices the broadband light from the source ( ) into two sub-bands, with different optical paths being defined between the source ( ) and detector ( ) for the light in the different spectrally sliced sub-bands. The two optical paths include separate phase modulators ( ) which modulate the two signals at different frequencies, and also separate delay loops ( ) at different places relative to the sensor loop ( ). Effectively, two separate Sagnac loops are provided with a single sensor loop ( ), source ( ) and detector ( ). Standard phase locked loop techniques can be used to extract information from signals that have passed through the two loops and to determine the location of a mechanical or thermal perturbation applied to the sensor loop ( ).