METHOD AND DEVICE FOR TIME DOMAIN DEMULTIPLEXING OF SERIAL FIBER BRAGG GRATING SENSOR ARRAYS

• Main Authors: SMITH, PETER W.E, COOPER, DAVID J.F
• Format: Patent
• Language: English; French
• Published: 08.04.2001
• Edition: 6
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; MEASURING QUANTITY OF HEAT; MEASURING TEMPERATURE; PHYSICS; TARIFF METERING APPARATUS; TESTING; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR

The present invention provides a method and device for to implement time division multiplexing of a fiber optic serial Bragg grating sensor arra y containing more than one Bragg grating. The device provides a pulse read-out system that allows for a reduction in system noise and an increase in sensor resolution and flexibility. The optical signals reflected from the Bragg grating sensors are gated by an electronically controlled optical modulator before a ny wavelength measurement is performed to determine the sensor information. Thi s offers significant advantages since the sensor information is encoded into t he wavelength of the optical signal and not its intensity. Therefore the sensor signal information is not distorted by the gating. Since the gating or switching of the optical modulator between transmission and attenuating states is performed o n the optical signal, the speed of the electronic processing needs only to be performed at the speed of variation of the sensor information and the choice of methods of wavelength measurement is not influenced by the gating action.</S DOAB>