Differential strain measurement using multiplexed fiber Bragg grating sensors

We investigate differential measurement of strain using fiber Bragg gratings and spatial demultiplexing methods. Differential measurement is shown to improve strain resolution in the presence of noise by an average of 34% compared to absolute measurements of the Bragg wavelengths. Spatial demultiplexing of the gratings provides potentially high-resolution sensing without calculating the sensor wavelengths. The differential method is still temperature dependent. We apply the differential technique to the problem of oil-water boundary detection in production columns, with promising preliminary results.