Demodulation of fiber bragg grating sensors based on dynamic tuning of a multimode laser diode.
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.
Ferreira
L A
LA
Unidade de Tecnologia Optoelectrónica e Electrónica, Instituto de Engenharia de Sistemas e Computadores, Porto, Portugal.
Diatzikis
E V
EV
Santos
J L
JL
Farahi
F
F