Optical fiber sensors play an important role in health monitoring of space shuttles, aviation vehicles, and civil structures to issue early warnings. In my research, a novel fiber sensor configuration using first and second order fiber Bragg gratings, coupled with Fourier demodulation technique, is investigated for simultaneously measuring strain and temperature. A detailed theoretical analysis for measurement resolution with regard to the sensor system matrix and the wavelength detection resolution was carried out for six different fiber grating based sensor configurations. Experimental methods to induce first and second order Bragg resonances in regular fiber gratings in single mode fibers were investigated. Far field (Fraunhofer field) diffraction intensity pattern in phase masks (dielectric surface relief gratings) was studied using simple plane wave electro-magnetic theory and the results were compared with the experimental results. A Fourier transform Bragg demodulator (FTBD) was built for simultaneously interrogating fiber gratings at   780 nm and 1550 nm wavelength ranges. The demodulator sensitivity and the grating sensor multiplexibility were investigated in terms of constraints arising from optical detectors, optical loss, and the spectral shape of the fiber gratings and mirrors. Finally, the measurement resolution of the whole sensor system was examined using simulated sensor data under two different laser tuning schemes; a single continuous sweep of the entire grating spectra and a multiple successive sweeps of the entire grating spectra. It was shown that the strain and temperature could be measured with a resolution of

Currently I am working on optical sensors for detecting chemical species using spectroscopic methods.

Experimental set up for testing FTBD system

Fiber Bragg grating fabrication set up

[ Home ] [ Up ] [ Laboratories ] [ Research ] [ Publications ] [ Events ] [ Faculty ] [ Education ] [ Useful Links ] [ Employment ]

Last modified: March 21, 2002