Fiber-optic refractometer based on a phase-shifted fiber Bragg grating on a side-hole fiber

Authors

Qi Zhang, University of Nebraska-Lincoln
Lingling Hu, University of Nebraska-Lincoln
Yuefeng Qi, University of Nebraska-Lincoln
G. Liu, University of Nebraska–LincolnFollow
Natale J. Ianno, University of Nebraska - LincolnFollow
Ming Han, University of Nebraska-LincolnFollow

ORCID IDs

https://orcid.org/0000-0002-2423-0463 Natale Ianno

Document Type

Article

Date of this Version

2015

Citation

OPTICS EXPRESS, Vol. 23, No. 13 (29 Jun 2015)

DOI:10.1364/OE.23.016750 |

Comments

© 2015 Optical Society of America. Used by permission.

Abstract

A fiber-optic refractive index (RI) sensor based on a π-phaseshifted fiber-Bragg-grating (πFBG) inscribed on a side-hole fiber is presented. The reflection spectrum of the πFBG features two narrow notches associated with the two polarization modes and the spectral spacing of the notches is used for high-sensitivity RI sensing with little temperature cross-sensitivity. The side-hole fiber maintains its outer diameter and mechanical strength. The side-hole fiber is also naturally integrated into a microfluidic system for convenient sample delivery and reduced sample amount. A novel demodulation method based on laser frequency modulation to enhance the sensor dynamic range is proposed and demonstrated.