Patents Assigned to FOCUS SENSORS LTD.
  • Distributed acoustic sensing
    Patent number: 10935398
    Abstract: Systems and methods for sensing changes in an optical sensing fibre, principally for detecting changes in strain. A plurality of optical probe pulses at different optical frequencies (f1, f2, . . . fn) spaced by ?f are transmitted into the sensing fibre. Light backscattered from the optical sensing fibre may be mixed with delayed backscatter frequency shifted by ?f+fm where fm is a heterodyne frequency. The backscattered or mixed light may be detected to determine changes in the sensing fibre. ?f may be chosen to optimise performance.
    Type: Grant
    Filed: January 12, 2018
    Date of Patent: March 2, 2021
    Assignee: FOCUS SENSORS LTD.
    Inventors: Edward Alfred Denzil Austin, Weizhong Zhao