Transmission characteristics of SMS fiber optic sensor structures

We examine theoretically the transmission characteristics of the Single mode-Multimode-Single mode (SMS) fiber structures when the spot sizes of the fundamental modes of the single and multimode fibers do not match. It is observed that in such cases, the transmitted power becomes highly sensitive to the wavelength of operation and the length of the multimode fiber used. The study should be useful in the design of efficient fiber optic microbend sensors and novel wavelength filters using SMS structures