In-fiber grating sensors

The period of in-fiber grating can be changed due to the change of pressure or temperature that the in-fiber grating bears. The reflecting wavelength of in-fiber grating will shift as its period changes. This characteristic t rait of in-fiber grating can render it to be used as a sensor element to de tect pressure or temperature. The key issue is how to interrogate the refle cting wavelength shift accurately. The techniques of in-fiber grating senso rs are reviewed with an emphasis on interrogation approaches to reflecting wavelength shift induced by measurement quantities. Some suggestions are al so made in this paper. (C) Published by Elsevier Science Ltd. All rights re served.