Browsing by Author "Ferraro, P."

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Laser-frequency locking techniques for high-sensitivity strain measurements by high-birefringence fiber Bragg gratings and resonators
    (International Society for Optical Engineering; 1999, 2007-12-31T00:00:00Z) Salza, M.; Gagliardi, G.; Di Maio, A.; Ferraro, P.; De Natale, P.; Chehura, Edmon; Tatam, Ralph P.; Antonello, Cutolo; Brian, Culshaw; José, Miguel López-Higuera
    A new approach to simultaneously interrogate orthogonal axes of single Fiber- Bragg-Gratings (FBGs) and FBG-FabryPerot resonator sensors fabricated in linearly highly birefringent (HiBi) fibre is presented. Novel interrogation techniquesof single Fiber-Bragg-Gratings (FBGs) and FBG-resonator sensors are presented. For a single FBG, we combined alaser-modulation technique to an electronic feedback loop that keeps the source always frequency locked to one peak ofthe sensor's reflected spectrum. Two different lasers, with orthogonally- polarized states, were adopted to monitorsimultaneously both the "fast" and "slow" FBG peaks. The corresponding correction signals from the servo-loop outputscan be interpreted as strain or temperature induced on the FBG. Detection limits ranging from 1 nε/√Hz to 100 nε/√Hz,for axial dynamic and static deformations, respectively, and of 0.025 °C/√Hz for temperature variations, are expected. Asimilar approach was developed for sub-pϵ resolution interrogation of an optical resonator made of a high-reflectivityFBG-pair, using the Pound- Drever-Hall (PDH) stabilizati
  • Thumbnail Image
    ItemOpen Access
    Optical fiber sensing based on reflection laser spectroscopy
    (MDPI , 2010-03-05T00:00:00Z) Gagliardi, G.; Salza, M.; Ferraro, P.; Chehura, Edmon; Tatam, Ralph P.; Gangopadhyay, T. K.; Ballard, N.; Paz-Soldan, D.; Barnes, J. A.; Loock, H-P; Lam, TT-Y; Chow, J. H.; De Natale, P.
    An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs) and FBG resonators built in fibers of different types are used for strain, temperature and acceleration measurements using heterodyne-detection and optical frequency-locking techniques. Silica fiber-ring cavities are used for chemical sensing based on evanescent-wave spectroscopy. Various arrangements for signal recovery and noise reduction, as an extension of most typical spectroscopic techniques, are illustrated and results on detection performances are presented.