title: Demodulation scheme for fiber bragg grating sensors based on active control of the spectral response of a wavelength division multiplexer.
abstract: We present a closed-loop technique for measuring wavelength shifts associated with fiber Bragg gratings by using a fused biconical wavelength division multiplexer (WDM). The spectral response of the WDM is actively tuned by stretching of the coupling region to maintain a fixed coupling ratio at the reflected Bragg wavelength. The closed-loop operation allows sensitivities usually associated with a highly selective WDM to be obtained without compromising the measurement range. A simple theoretical model is presented together with experimental results for temperature and strain measurements.
authors.forename: F M
authors.initials: FM
authors.lastname: Araújo
authors.forename: L A
authors.initials: LA
authors.lastname: Ferreira
authors.forename: J L
authors.initials: JL
authors.lastname: Santos
authors.forename: F
authors.initials: F
authors.lastname: Farahi