RESUMO
This article presents a technique for reducing the stabilization length of steady-state modes in step-index plastic optical fibers (POFs), which is significant for sensor networks, Internet of Things, signal processing, and data fusion in sensor systems. The results obtained with the com- putational tool developed suggest that the D-shape created in the POF effectively reduces the stabi- lization length of the modes and, by extension, minimizes the dispersion effects of the modes by filtering out high-order modes. Applying the analysis to commercial POFs, the authors experimen- tally verified a reduction in the stabilization length of modes from 27 to 10 m and from 20 m to 5 m. Reducing the mode stabilization length minimizes the bit error rate (BER) in short-length SI-POF- based optical links operating at 250 Mbp/s. A reduction from 7.6 × 10-7 to 3.7 × 10-10 was achieved.
RESUMO
In this work, we present an analysis of the influence of geometrical parameters on the sensitivity and linear range of a fiber optic angular displacement sensor, through computational simulations and experiments. The geometrical parameters analyzed are the lens focal length, the gap between fibers, the fiber cladding radii, the emitting fiber critical angle (or, equivalently, the emitting fiber numerical aperture), and the standoff distance (distance between the lens and the reflective surface). Besides, we analyze the sensor sensitivity regarding any spurious linear displacement. The simulation and experimental results show that the parameters that play the most important roles are the emitting fiber core radius, the lens focal length, and the light coupling efficiency, whereas the remaining parameters have little influence on the sensor characteristics.