Mechanical Properties of Optical Fibers

In-fiber Mach-Zehnder interferometer for gas refractive index measurements based on a hollow-core photonic crystal fiber

“…The sensitivity coefficients may then be estimated with Eq. (9) and are between f = 7 × 10 −5 , 5 × 10 −4 and 4 × 10 −2 , showing that it is difficult to obtain strong interaction of the propagated modes in the sensing arm with the sample liquid.…”

“…the area of the center hole with diameter 10 µm and of 294 holes with a diameter of 3.8 µm. The Young modulus of the fiber E = 16.56 ± 0.39 GPa was previously determined for a fiber coated by a polymer jacket [9]. The contribution of the pressure-induced expansion of the PCF is ΔL/ΔP = 1.9 × 10 −12 m Pa −1 and is negligible compared to the δn i /δP terms.…”

Embedded fiber-optic sensing for accurate internal monitoring of cell state in advanced battery management systems part 1: Cell embedding method and performance

“…The The FBG sensors can monitor strain and temperature with linearly proportional wavelength shifts until the linear elastic material limits of the silica optical fiber or its coating, especially when the FBG sensors are inscribed by a method that does not compromise fiber integrity, such as the draw tower grating approach reported in [24]. For silica optical fibers with one of the common coatings, acrylate, this strain limit is between 2.5% and 4% [25].…”

A Multisensing Setup for the Intelligent Tire Monitoring

“…The value of the Bragg reflection wavelength depends on the effective refractive index, $n_{eff}$, and on the grating period, Λ, according to Equation (1), as presented by Antunes [38]: ${\mathsf{\lambda }}_{\mathrm{B}}=2{\mathrm{n}}_{\mathrm{eff}}\mathrm{sans-serif\Lambda }$ when the FBG sensor is stretched, or compressed, ${\lambda }_B$ changes to $\lambda$, therefore, if the sensor is integrated with the point to measure, for example welding or pasting it to the monitored structure, the reflected wavelength changes are related to the strain and to the thermal variation, as described in Equation (2): $\frac{\mathrm{normal\Delta }\lambda }{{\lambda }_B}=\left(1-{\rho }_e\right)\epsilon +\left(\alpha +\eta \right)\mathrm{normal\Delta }T$ where $\Delta \lambda =\lambda -{\lambda }_B$, ${\rho }_e$ represents the photo-elastic coefficient, $\epsilon$ is the mechanical strain, $\alpha$ is the thermal expansion of the silica, $\eta$ represents the temperature dependence of the refractive index, and $\Delta T$ is the temperature variation.…”