Abstract

Fiber-Bragg gratings (FBGs) are proving to be suitable for providing the basis of a range of new fiber devices for use in both the fiber communications and sensing areas.¹ In the communications field, current attention is directed in particular on the development of grating-based WDM devices and dispersion compensators, whereas in sensing, grating-based sensors are being developed for multipoint structural-strain monitoring systems and other embedded sensor applications. In such sensing applications, the inherently wavelength-encoded output of Bragg gratings has a number of distinct advantages over other sensing schemes. One of the most important of these is that because the sensed information is encoded directly into wavelength, which is an absolute parameter, the output does not depend directly on the total light levels, losses in the connecting fibers and couplers, or source power. Consequently, the sensor can easily be operated intermittently without the need for recalibration or reinitialization of the system. The wavelength-encoded nature of the output also facilitates WDM by assigning each sensor to a different slice of the available source spectrum. Additionally, TDM can be used to augment the WDM to improve the multipoint sensing capabilities.

© 1995 Optical Society of America