Enhancement of FBG Multiplexing Capability Using a Spectral Tag Method

Multiplexing of fiber Bragg grating (FBG) sensors is one of the most effective technologies to reduce both installation and operation costs for quasi-distributive strain and temperature measurements such as smart structure applications. We propose a novel method of enhancing the multiplexing capability of a multipoint FBG sensor system without increasing system complexity by providing a unique spectral response as an identification tag to each FBG. The number of sensors in the proposed spectral tag method can increase as N ( N -1)/2 as the number of spectral codes N increases at the expense of the free spectral range.