Optical fiber sensor for simultaneous measurement of strain and temperature

An optical fiber sensor for simultaneous measurement of axial strain and temperature is reported. This sensor configuration consists of an in-line fiber etalon cascaded with a in-fiber Bragg grating and demultiplexed using a variation of coherence division multiplexing. The strain/temperature sensor is demonstrated by bonding it to the surface of an aluminum cantilever beam and embedding it into a graphite/epoxy composite cantilever beams. They are found to agree with traditional strain and temperature sensors to within 5 (mu) (epsilon) and 0.5 degree(s)C, respectively for a sensor gage length of approximately 1.0 cm.