Effect of Wet Etching of Arc-Induced Long-Period Gratings on Their Refractive Index Sensitivity

Abstract

The paper presents highly refractive index sensitive operation of long-period gratings enhanced by wet etching of the ber cladding. Long-period gratings with period of 283 m were induced in Corning SMF28 optical bre using electric arc technique. Then etching in hydrouoric (HF) acid solution has been applied to improve operation of the sensor. Sensitivity improvement eect induced by ber cladding reduction has been numerically simulated. The developed numerical model enables quick estimation of cladding thickness reduction essential to achieve dispersion turning point. At this point long-period gratings reaches maximum sensitivity to external medium refractive index.