A system for the interrogation of fiber Bragg grating sensors using a strain-tuned EDF laser with linear cavity is described. An optical switch is spliced to one end of the laser cavity and connects one of two high-strength draw-tower fiber Bragg gratings (DTG). The gratings are simultaneously tuned by a stretching device and act as the end reflector of the laser cavity. By applying a ramp signal to the actuator synchronized to the optical switch, the laser signal sweeps over two different wavelength intervals, depending on the connected DTG. This approach represents a hybrid wavelength-time domain interrogation for multiplexed sensors and doubles the number of sensors that may be addressed when compared with single DTG scanning. In addition, the use of the DTG allows a fivefold increase in the strain tuned wavelength interval over standard fiber Bragg gratings. An example application is demonstrated where the temperature in an electrical motor is measured during the machine operation.

Date Published: 2 July 2007
PDF: 4 pages
Proc. SPIE 6619, Third European Workshop on Optical Fibre Sensors, 66193F (2 July 2007); doi: 10.1117/12.738581

Published in SPIE Proceedings Vol. 6619:
Third European Workshop on Optical Fibre Sensors
Antonello Cutolo; Brian Culshaw; José Miguel López-Higuera, Editor(s)