Dual temperature and strain measurement with the combined fluorescence lifetime and Bragg wavelength shift approach in doped optical fiber

We have constructed fiber-optic sensors to measure temperature and strain by combining the properties of fiber Bragg gratings with the fluorescent lifetimes of various doped fibers. Sensors have been made with the fiber Bragg grating written directly into the doped fiber to ensure the collocation of the strain and temperature measurement points. Results are compared with those obtained previously from a Bragg grating written into standard photosensitive fiber spliced to doped fiber. Standard deviation errors of 7 microepsilon and 0.8 degrees C have been obtained for strain and temperature ranges of up to 1860 microepsilon and 120 degrees C, respectively.