Heterodyne interrogation system for TDM interferometric fiber optic sensors array

We proposed an interrogation system for time sequenced fiber optic sensors array based on the heterodyne detection and orthogonal demodulation techniques, where the sensors array is a kind of interferometric fiber optic sensors. The techniques are theoretically analyzed and experimentally demonstrated with recovering the sinusoid wave and triangle wave applied to the sensors. The system has a phase resolution about 1×10−4 rad/√Hz, the amplitude consistency and linearity of the demodulated results are 95.275% and 98.379%, respectively with single frequency event applied to the sensors.