Simultaneous measurement of strain (to 2000 μϵ) and temperature (to 600°C) using a combined Sb-Er-Ge-codoped fiber-fluorescence and grating-based technique

An optical fiber-based sensing scheme for the simultaneous measurement of strain and temperature over a wider range has been demonstrated by writing a grating with very high reflectivity in a 10-cm-long specially fabricated antimony-erbium-germanium (Sb-Er-Ge)-doped silica fiber. The scheme exploits the grating sensitivity to both strain and temperature in association with the temperature-dependent peak power ratio of the two fluorescence peaks around 1535 and 1552 nm of the amplified spontaneous emission due to ⁴I₁₃2/→⁴I₁₅2/ transition arising from the presence of erbium ions in the fiber core, using a 980-nm laser diode as a pumping source. The sensor created using this fiber can be used for the simultaneous measurement of strain and temperature over the wide ranges of 0-2000 με and 20°C-600°C, with root-mean-square errors of 36 με and 2.8°C, respectively.