Simultaneous measurement of strain and temperature using Bragg gratings written in germanosilicate and boron-codoped germanosilicate fibers

A new fiber Bragg grating sensor configuration is presented for simultaneous measurement of strain and temperature. The sensor utilizes the effect of boron codoping on the temperature dependence of the refractive index in germanosilicate fibers. By writing gratings with dose wavelengths in undoped acid boron doped fibers, different temperature sensitivities are obtained while strain sensitivities remain the same. These gratings are then spliced to obtain a simple sensor head suitable for applications in smart structures and composite materials.