Temperature-insensitive multipoint strain-sensing system based on fiber Bragg gratings and optical power detection scheme

This work presents a new temperature-insensitive multipoint strain sensor based on fiber Bragg gratings. A divider circuit at the post detection port compensates for optical power variation and thermal instability induced by the nonflatness of the source spectrum. Experimental results show a measurement resolution of /spl plusmn/0.35 /spl mu/S and a temperature stability of /spl plusmn/0.005% for no strain (/spl plusmn/0.48% for a strain of <400 /spl mu/S) in an example with two sensing points. A measurement linearity of /spl plusmn/0.17% is estimated in the range 0 to 350 /spl mu/S with no crosstalk.