An optical fiber hydrogen concentration sensor based on Mach-Zehnder interferometer coated with a film of palladium

An optical fiber hydrogen sensor based on Mach-Zehnder interferometer was proposed. The Mach-Zehnder interferometer is composed of a waist-narrowed taper, a waist-enlarged taper and a single mode fiber. The SMF between two tapers was coated with a film of palladium. The energy distribution of the optical fiber sensor was analyzed by using the finite element means. Hydrogen detection sensitivity reaches about two times than the others with an exponential correlation coefficient of 96.9% under the hydrogen concentration range of 0%-3.6%.