Adaptive Neuro-Fuzzy Evaluation of the Tapered Plastic Multimode Fiber-Based Sensor Performance With and Without Silver Thin Film for Different Concentrations of Calcium Hypochlorite

An adaptive neurofuzzy (ANFIS) evaluation study has been applied on tapered plastic multimode sensors. This study is basically using tapered plastic multimode fiber polymethyl methacrylate (PMMA) optical as a sensor. It is proposed and demonstrated for continuous monitoring of solutions based on different concentration of sodium chloride and glucose in deionized water. The tapered PMMA fiber was fabricated using an etching method involving deionized water and acetone to achieve a waist diameter and length of 0.45 and 10 mm, respectively. In addition, a tapered PMMA probe, which was coated by silver film, was fabricated and demonstrated using calcium hypochlorite (G70) solution. The working mechanism of such a device is based on the observation increment in the transmission of the sensor that is immersed in solutions at higher concentration. As the concentration varies from 0 to 6 ppm, the output voltage of the sensor increases linearly from 3.61 to 4.28 mV with a sensitivity of 0.1154 mV/ppm and a linearity of more than 99.47%. The silver film coating increases the sensitivity of the proposed sensor due to the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber. To estimate the output voltage response of the sensors with and without silver film, this paper constructed a process, which simulates the sensors voltage output in regard to different concentration of calcium hypochlorite with ANFIS method. This intelligent estimator is implemented using MATLAB/SIMULINK and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.