Dynamic mechanical analysis on fused polymer optical fibers: towards sensor applications

Abstract

This Letter presents, for the first time, to the best of our knowledge, the dynamic mechanical analysis of a polymer optical fiber (POF) that was previously damaged by the catastrophic fuse effect. The variation of the fiber Young's modulus was evaluated with respect to the increase of temperature, humidity, and frequency of strain cycles. The obtained data for the fused POF are compared with the ones for the same POF without the fuse effect. The results show the feasibility of the fused POF for sensor applications, such as strain and acceleration measurement, since it presents temperature sensitivity almost two times lower in temperatures between 26°C and 90°C and Young's modulus 2.3 times lower than those obtained with the bare fiber. The Young's modulus variation with the humidity is 1.5 MPa/%RH in a humidity range of 66-96%. In addition, the fused POF presented a variation of its dynamic modulus with the frequency increase four times lower than non-fused POFs on the range of 0.01-100.00 Hz. These results pave the way for future applications of fused POFs as sensing elements.

Design and characterization of a curvature sensor using fused polymer optical fibers

“…Note that this value is two orders of magnitude lower than that reported for PMMA-based POF at this angular velocity (∼1.2%) [5]. The reason for this difference may be related to the higher R 2 of the stress-strain curve of the fused POF [18]. Another reason may be the fact that the fused POF shows lower Young's modulus dependence with the frequency variations than the non-fused POF [18].…”

“…The reason for this difference may be related to the higher R 2 of the stress-strain curve of the fused POF [18]. Another reason may be the fact that the fused POF shows lower Young's modulus dependence with the frequency variations than the non-fused POF [18]. Next, the influence of flexion/extension cycle frequency on the angle sensitivity of the POF samples were analyzed by changing the angular velocities (0.48 rad/s, 0.55 rad/s, 1.05 rad/s, 4.55 rad/s, and 5.61 rad/s made in the range between 0 deg and 90 deg, whereas 2.55 rad/s and 3.35 rad/s performed in the range of 0 deg to 50 deg due to experimental limitations).…”

“…Unlike the case of the silica fiber fuse, light can still propagate through the fused POFs, but with a high attenuation of ∼1.4 dB∕cm [15]. In addition, the mechanical characterization of the fused POFs [18] indicates that they have some advantages over the same type of non-fused POFs for elastic deformation sensing applications (strain, curvature, etc. ), especially when the deformation is dynamically applied.…”

“…The higher sensitivity of the fused POF may be attributed to its higher optical propagation losses. Also, the higher R 2 of the fused POF may be originated from its highly linear relationship between stress and strain, when compared with the non-fused POF [18].…”

“…Next, the influence of flexion/extension cycle frequency on the angle sensitivity of the POF samples were analyzed by changing the angular velocities (0.48 rad/s, 0.55 rad/s, 1.05 rad/s, 4.55 rad/s, and 5.61 rad/s made in the range between 0 deg and 90 deg, whereas 2.55 rad/s and 3.35 rad/s performed in the range of 0 deg to 50 deg due to experimental limitations). Since the power-attenuation mechanism of the POFs includes the stress-optic effect [11], the variations in the Young's modulus [18] can lead to stress variations, which result in different attenuation characteristics. Hence, if the material properties of the POF change with the frequency or, in this case, angular velocity, there may be a cross-sensitivity of the angle sensitivity with respect to the angular velocity.…”