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.

Fiber optic sensors; Heterodyne; Orthogonal demodulation

Institute of Semiconductors, Chinese Academy of Sciences