Novel Schiff base functionalized 80-μm tilted fiber Bragg grating chemosensor for copper(II) ion detection

A novel Schiff base functionalized tilted fiber Bragg grating (TFBG) is developed for the rapid detection of Copper ions in aqueous solutions. Notably, the proposed TFBG was inscribed in a commercial 80 μm diameter single-mode fiber that has a stronger evanescent field and functionalized with Schiff base that has a strong affinity with copper(II) ions. The findings indicate that the 80-μm TFBG is more superior to the TFBG inscribed in the 125-μm diameter standard optical fiber in terms of higher sensitivity, a lower limit of detection, and less susceptibility to refractive index noise. Furthermore, the proposed sensor is a silica glass-based optical component that can be reused multiple times via chemical stripping followed by a functionalization process. The results show that there is no sign of alteration and degradation in its optical spectrum after 24 times of chemical stripping processes.