Time division multiplexing of a serial fibre optic Bragg grating sensor array

A method of multiplexing fibre optic Bragg grating strain sensors is developed. The proposed design is shown to be capable of meeting the requirements demanded by applications in modern civil engineering constructions. The system is implemented using a mode-locked erbium doped fibre laser as the interrogation source and an electro-optic modulator to demodulate the strain encoded sensor information. Both experimental and theoretical analysis is used to examine the system performance.; The requirements of civil engineers for multiplexing fibre optic sensors were identified and the proposed system was shown to meet them. Some of the particular advantages of the system include simple integration with existing single grating sensor measurement methods, a sensing range capable of monitoring many structures up to the failure point, relaxed demands on the manufacture of the grating sensors and high sensor spatial resolution.