Sensitivity optimization of U-shaped fiber optics based on the Taguchi method

Abstract

The structure of macrobending fiber optics is an ideal structure for constructing fiber optic sensors. This study presents a new design and implementation of U-shaped fiber optics. The basic geometric parameters of U-shaped fiber optics, such as dimension size or curve radius, are analyzed. The Taguchi method was used to optimize the effects of the control and noise factors with respect to dimension size, loop, wavelength, and core size. The control factors were varied at different levels to achieve a novel sensitivity response optimization of the wavelength and core size. The quality characteristics of the signal-to-noise ratio (larger-the-better characteristics) were used to determine the effect of the control parameters in the data analysis. The data of the sensitivity response was analyzed to predict the performance of the U-shaped fiber optics. Results indicate that, by using the Taguchi method, the best control factor setting involves 2.5 cm × 1.5 cm (dimension size) and 1550 nm (wavelength). The percentage contribution of wavelength is the highest at 67.17%, followed by dimension size (13.31%) and number of loops (11.72%) for the fiber optic core size of 50–9–50 μm. For the 9 μm single-mode fiber optics, the corresponding percentages are 61.48%, 16.64%, and 12.81% for wavelength, dimension size, and number of loops, respectively. The Taguchi methodology is suitable for designing sensor geometry.

Investigation of U-shaped plastic optical fiber as refractive index sensor for liquids assessment

“…The refractive index of a liquid contains crucial information about its physical characteristics, such as concentration and density, allowing the solution's composition to be determined and monitored such as the concentration of the medication in pharmaceutical manufacturing [8] and contamination in water [9]. There are a few types of geometries modified for plastic optical fiber for sensing purpose, for instance, a D-type, U-type shaped, uncladded, reflectance-based and others [3], [2], [10], [11]. Among these approaches, the U-shaped method has been examined and studied by many researchers because of its benefits such as ease of fabrication, simple experiment setup, and it suited for any point sensing due to its sensitivity, particularly for detecting a liquid's concentration and fat [12]- [14].…”

“…If the modes increase, the evanescent field will increase [22]. The effect of curvature radii and their angle were investigated to explore which sensor has the low-loss performance and give the best parameter of a suitable U-shaped RI sensor for the liquid environment [11]. The expected output of this sensor is to determine the sensor range sensitivity, the suitable polished angle, the propagation loss and cut of sensitivity, the optimum curvature radii, the optimum length, and the ideal temperature [23]- [25].…”