Fiber Bragg grating based pH sensor

This paper presents the modeling of pH sensor based on pH sensitive hydrogel coated fiber Bragg grating. The modeling was done by simulating the hydrogel swelling behavior, then calculating the strain induced by hydrogel expansion. The strain was then used to calculate the shift of λ_B of the fiber Bragg grating. Meshless numerical method is adopted to solve the Poison Nerst Planck equation coupled to mechanical equation to simulate the hydrogel swelling.