ACTIVE WAVELENGTH DEMODULATION OF A BRAGG GRATING FIBER OPTIC STRAIN SENSOR USING A QUANTUM-WELL ELECTROABSORPTION FILTERING DETECTOR

The first demodulation of a Bragg grating fibre optic sensor using a s emiconductor quantum well electroabsorption device as a filtering dete ctor is reported. The tunable wavelength response of an InGaAs/InP qua ntum well filtering detector was used in an active manner to track the wavelength of reflected signals from an intracore Bragg grating senso r. A wavelength resolution of +/-9.65pm was achieved with a Bragg grat ing fibre optic strain sensor operating at similar to 1535nm, correspo nding to a strain resolution of +/-8.04 mu epsilon.