title: Dual-peak long-period fiber gratings with enhanced refractive index sensitivity by finely tailored mode dispersion that uses the light cladding etching technique.
abstract: We have experimentally investigated the mode dispersion property and refractive index sensitivity of dual-peak long-period fiber gratings (LPGs) that were sensitized by hydrofluoric acid (HF) etching. The nature of the coupled cladding modes close to the dispersion turning point makes the dual-peak LPGs ultrasensitive to cladding property, permitting a fine tailoring of the mode dispersion and index sensitivity by the light cladding etching method using HF acid of only 1% concentration. As an implementation of an optical biosensor, the etched device was used to detect the concentration of hemoglobin protein in a sugar solution, showing a sensitivity as high as 20 nm/1%.
authors.affiliation: Department of Electronic Engineering, Aston University, Birmingham, UK. chenx2@aston.ac.uk
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Chen
authors.forename: Kaiming
authors.initials: K
authors.lastname: Zhou
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Ian
authors.initials: I
authors.lastname: Bennion