All-fiber hybrid fiber Bragg gratings cavity for sensing applications

Abstract

By now, fiber Bragg gratings (FBGs) represent a well assessed technology in sensing field. Unfortunately, to make FBGs sensitive to surrounding refractive index, hosting fiber structuring is needed. In last years, also tilted FBGs (TFBGs) have been proposed as promising technological platform for sensing applications. However, complex spectral features limit the practical exploitation of this technology. It would be extremely useful to merge the peculiar spectral characteristics of both grating types. To address this issue, here, we propose a hybrid cavity involving two unbalanced uniform FBGs written at both sides of a TFBG. The proposed configuration provides a wavelength gated reflection signal. Such a structure preserves uniform FBG advantages in terms of interrogation methods and allows the possibility to contemporarily measure multiple parameters. © 2010 Springer Science+Business Media B.V.