Abstract

We report a high sensitive refractive index (RI) sensor using fiber Bragg grating (FBG) where azimuthally symmetric resonant cladding modes were used for RI sensing. We enhanced the sensitivity by tailoring the effective index of a cladding mode to an optimum value so that the mode has maximum sensitivity around a specific surrounding RI. We tailored the effective index of a clad mode by controlled deposition of a thin polymer layer having RI higher than the cladding. Experiments show that the sensitivity of cladding mode (LP_0,12) of a standard FBG with overlay coating to the surrounding medium having RI around 1.333 is ∼ 2600 pm/RIU. The proposed sensing mechanism will be useful for biological sensing application.

© 2016 IEEE

High-refractive-index transparent coatings enhance the optical fiber cladding modes refractometric sensitivity

Jean-Michel Renoirt, Chao Zhang, Marc Debliquy, Marie-Georges Olivier, Patrice Mégret, and Christophe Caucheteur
Opt. Express 21(23) 29073-29082 (2013)

Mode transition in high refractive index coated long period gratings

A. Cusano, A. Iadicicco, P. Pilla, L. Contessa, S. Campopiano, A. Cutolo, and M. Giordano
Opt. Express 14(1) 19-34 (2006)

Cladding mode reorganization in high-refractive-index-coated long-period gratings: effects on the refractive-index sensitivity

Andrea Cusano, Agostino Iadicicco, Pierluigi Pilla, Luigi Contessa, Stefania Campopiano, Antonello Cutolo, and Michele Giordano
Opt. Lett. 30(19) 2536-2538 (2005)

Towards refractive index sensitivity of long-period gratings at level of tens of µm per refractive index unit: fiber cladding etching and nano-coating deposition

Mateusz Śmietana, Marcin Koba, Predrag Mikulic, and Wojtek J. Bock
Opt. Express 24(11) 11897-11904 (2016)

Refractive index sensitivity enhancement of optical fiber cladding mode by depositing nanofilm via ALD technology

Ying Zhao, Fufei Pang, Yanhua Dong, Jianxiang Wen, Zhenyi Chen, and Tingyun Wang
Opt. Express 21(22) 26136-26143 (2013)