title: Demodulation of fiber bragg grating sensors based on dynamic tuning of a multimode laser diode.
abstract: Dither demodulation of fiber Bragg grating sensors illuminated with multimode light from laser diodes is theoretically and experimentally investigated. Quasi-static temperature and strain sensitivities of 0.09 degrees C/ radical Hz and 0.6 microepsilon/ radical Hz are obtained. We show that it is possible to measure small ac signals that lie outside the feedback loop bandwidth by using a synchronous detection referenced to twice the dither frequency. In this situation, dynamic strain sensitivity of 3.3 n(epsilon)/ radical Hz is achieved.
authors.affiliation: Unidade de Tecnologia Optoelectrónica e Electrónica, Instituto de Engenharia de Sistemas e Computadores, Porto, Portugal.
authors.forename: L A
authors.initials: LA
authors.lastname: Ferreira
authors.forename: E V
authors.initials: EV
authors.lastname: Diatzikis
authors.forename: J L
authors.initials: JL
authors.lastname: Santos
authors.forename: F
authors.initials: F
authors.lastname: Farahi