High-resolution distributed-feedback fiber laser dc magnetometer based on the Lorentzian force

G.A. Cranch, Gordon M.H. Flockhart, C.K. Kirkendall

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


A low-frequency magnetic field sensor, based on a current-carrying beam driven by the Lorentzian force, is described. The amplitude of the oscillation is measured by a distributed-feedback fiber laser strain sensor attached to the beam. The transduction mechanism of the sensor is derived analytically using conventional beam theory, which is shown to accurately predict the responsivity of a prototype sensor. Excellent linearity and negligible hysteresis are demonstrated. Noise sources in the fiber laser strain sensor are described and thermo-mechanical noise in the transducer is estimated. The prototype sensor achieves a magnetic field resolution of 5 nT Hz for 25 mA of current, which is shown to be close to the predicted thermo-mechanical noise limit of the sensor. The current is supplied optically through a separate optical fiber yielding an electrically passive sensor head.
Original languageEnglish
Article number034023
Number of pages12
JournalMeasurement Science and Technology
Issue number3
Publication statusPublished - Mar 2009


  • beam characteristics
  • intensity
  • spatial pattern formation
  • dynamical laser instabilities
  • noisy laser behavior
  • fiber lasers
  • magnetometers
  • magnetic field measurements


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