Two-sensor multiplexing in a split-cavity cross-coupled extrinsic fiber interferometer

A multiplexed configuration of the fiber optic extrinsic Fabry-Perot interferometer is demonstrated by using two sensor heads on a single directional coupler in a split-cavity cross- coupled extrinsic fiber interferometric (SCEFI) arrangement. The provision of four-beam interference along with a spectrum analysis detection scheme devised for the SCEFI eliminates the need for quadrature phase biasing and leads to independent measurements of the phase shift in the two sensor heads. Good agreement between the experimental results and the model for interference is demonstrated.