  In this work, we present an analysis of the influence of the geometrical
parameters on the sensitivity and linear range of the fiber optic angular
displacement sensor, through computational simulations and experiments. The
geometrical parameters analyzed were the lens focal length, the gap between
fibers, the fibers 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 analyzed
the sensor sensitivity regarding any spurious linear displacement. The
simulation and experimental results showed that the parameters which play the
most important roles are the emitting fiber core radius, the lens focal length,
and the light coupling efficiency, while the remaining parameters have little
influence on sensor characteristics.
  This paper was published in Applied Optics and is made available as an
electronic reprint with the permission of OSA. The paper can be found at the
following URL on the OSA website:
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-53-36-8436. Systematic or
multiple reproduction or distribution to multiple locations via electronic or
other means is prohibited and is subject to penalties under law.
