<title>Fiber optic weigh-in-motion sensor: correlation between modeling and practical characterization</title>

Abstract

This paper shows the way to turn a defect inherent to single-mode fiber, namely birefringence, into a prime quality for a powerful and reliable sensor. The latter is entirely devoted to Weigh-In-Motion (WIM) applications extended to complete active traffic management systems. After a brief description of the sensor and its principle of operation, the theoretical model is developed. Then, a full characterization made in both static and dynamic conditions is presented. The results obtained illustrate how it is difficult to interpret a weight measured in dynamic conditions and correlate the value with the static weight.

<title>Polarimetric optical fiber sensor for weight-in-motion applications</title>

“…As there is no similarity in the modulators' construction, we believe that the hysteresis is caused either by cladding exhibiting inelastic properties or by shear stress present due to nonuniform force application to the modulator. Comparing to the data form [3] the hysteresis in our modulator is lower, probably due to lower value of maximal stress applied.…”

“…Such sensor has already been described in [3]. Measurement results presented there show, however, significant hysteresis reducing its performance.…”

“…Typical results of these measurements are shown in Figure . Hysteresis in a polarimetric sensor has already been reported in [3], where a different modulator type has been used. As there is no similarity in the modulators' construction, we believe that the hysteresis is caused either by cladding exhibiting inelastic properties or by shear stress present due to nonuniform force application to the modulator.…”

A Special Fiber Optic Sensor for Measuring Wheel Loads of Vehicles on Highways

“…Due to these positive attributes of optical fibers, efforts have been directed towards developing sensors for civil engineering infrastructures, including WIM systems and bridge monitoring, using fiber optics technology [ 10 - 24 ]. Optical fiber techniques proposed for WIM systems, include those based on light polarization and interferometry [ 10 , 15 , 17 , 23 ], bending loss, modulation of light intensity through an optical fiber having a single core [ 11 , 13 , 14 ], and on the concept of bragg grating [ 19 , 20 , 24 ]. However, none of these have found widespread practical use so far.…”

“…Other fiber optic techniques investigated for WIM systems include those based on light polarization, interferometry [ 10 , 15 ]; measurement of transmitted light intensity through the fiber having a single core [ 11 , 13 , 14 ]; and on the concept of fiber Bragg grating [ 17 , 18 , 14 ]. Interferometric techniques are complicated and require a different interferometer for each fixed sensing point, separated from other interferometers by a system of fiber optic couplers.…”