Citation:
M. Salza, G. Gagliardi, A. Di Maio, P. Ferraro, P. De Natale, E. Chehura, R. Tatam, Laser-frequency locking techniques for high-sensitivity strain measurements by
high-birefringence fiber Bragg gratings and resonators, Third European Workshop on Optical Fibre Sensors, Napoli, Italy, 4th of July 2007, Pages 661915-1-661915-4.
Abstract:
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
