Simultaneous measurement of strain (to 2000 /spl mu//spl epsiv/) and temperature (to 600/spl deg/C) using a combined Sb-Er-Ge-codoped fiber-fluorescence and grating-based technique

Abstract

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 /sup 4/I/sub 13/2//spl rarr//sup 4/I/sub 15/2/ 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 /spl mu//spl epsiv/ and 20/spl deg/C-600/spl deg/C, with root-mean-square errors of 36 /spl mu//spl epsiv/ and 2.8/spl deg/C, respectively.