Time division multiplexing of FBG sensor system

A novel fiber Bragg grating (FBG) sensor system for measurement of strain and temperature is proposed in this paper. The proposed sensor technique is based on time division multiplexing (TDM). A semiconductor optical amplifier (SOA) connected in a ring cavity is used to serve as a gain medium and switch. The SOA is driven by a pulse generator which switch on the SOA at different periods, as a switch to select the reflected pulses from a particular sensor. The FBG sensors have identical center wavelengths and can be deployed along the same fiber. This technique relieves the spectral bandwidth issue and permits the interrogation of up to 100 FBGs along a fiber. The sensor system has a fast signal process and control unit, which have a typical scan frequency in 1 kHz and self-adaptive measurement for simple sensor array installation.