Temperature and Strain Measurement Using a Combined Fiber Bragg Grating and Fluoresence Intensity Ratio in Er3+-Doped Fiber

Overcoming the temperature cross sensitivity inherent in optical fiber strain sensors is currently of much interest. Many groups are investigating this cross-sensitivity in Bragg grating (FBG) sensors by seeking ways to have both parameters determined simultaneously from two separate sensor elements having different temperature and strain responsivities. It is therefore of interest to take advantage of the strain insensitivity of the fluorescence intensity ratio (FIR) technique by splicing a length of rare-earth-doped fiber to a FBG sensor. This paper reports initial measurements of temperature and strain using the proposed sensing scheme, in erbium-doped fibre