Measurements of Strain and Temperature with Embedded Intrinsic Fabry-Perot Optical Fiber Sensors

The use of embedded intrinsic Fabry-Perot sensors in measuring strains and temperature changes was explored. Tests were performed with intrinsic Fabry-Perot sensors embedded in plates made of Fiberite T300/976 graphite-epoxy and of Fiberite APC2-PEEK graphite thermoplastic unidirectional tapes. The plates were also in strumented with thermocouples and strain gauges. The plates were subjected either to three point bending at room temperature, or to a uniform temperature change without an applied external stress. The temperatures and strains measured by the Fabry-Perot sensors agreed well with the thermocouple and strain gauge data, showing that with a single sensor and a single, constant wavelength light source, either the axial strain component or the temperature change can be measured.