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Firstly, we propose the embedded-core capillary fiber structure for acting as a pressure sensor. Analytical and numerical studies were performed and showed that high pressure sensitivity could be achieved with this simplified fiber structure, which consists of a capillary structure with a germanium-doped core placed within the capillary wall.
Experiments allowed measuring a sensitivity of 1.
Moreover, we studied the so-called surface-core optical fibers, which are fibers whose cores are placed at the external boundary of the fiber. In this approach, Bragg gratings were used to obtain refractive index — making use of the interaction between the guided mode evanescent field and the external medium — and directional curvature sensors — by exploring the off-center core position.
Additionally, antiresonant polymer capillary fibers were investigated as temperature and pressure sensors. For the temperature sensing description, one used an analytical model to simulate the transmission spectra of such fibers and the dependence on temperature variations. Regarding the pressure sensing application, pressure-induced capillary wall thickness variations were analytically accounted and related to the system pressure sensitivity.
In both these applications, experimental data were presented. Finally, additional opportunities using specialty optical fibers were presented, namely, a photonic-crystal fiber-based dual-environment pressure sensor, a three parameters sensor using Bragg gratings, tapered fibers and multimode interference, a liquid-level sensor based on Bragg gratings and multimode interference, and a temperature sensor based in an embedded-core fiber filled with indium.
The results reported herein demonstrates the potential of optical fibers for providing sensing platforms to attain measurements of different sort of parameters with highly sensitivity and improved resolutions.
With the exception of polarization-maintaining fibers, usually the polarization of the wave evolves randomly in the fiber because of the residual fiber birefringence. However, residual birefringence can be canceled by twisting the fiber, which at the same time introduces a known circular birefringence .
Despite the additional circular birefringence effect, twisted fibers have very useful properties for nonlinear applications [6,7]; for instance, it was experimentally shown that the radiation generated in the process of pulse breakup and subsequent SSFS in twisted fibers evolves towards Raman-shifted light pulses that tend to be circularly polarized .
We introduce here the wavenumbers k 1k 2 k 3and k 4which reflect the difference of the wavenumbers between right Research Article and left circularly polarized components.
This difference can be caused by circular birefringence introduced by twisting the fiber and also by the effect of the nonlinear polarization rotation [5, 6].
In the following analysis, we assume that the differences between the phase velocities of the circular components are large enough and independent, so that the relative orientation of polarization ellipses for signal and pump waves changes rapidly at the scale of the Raman amplification length along the propagation direction.The effect of stress can be delayed for days, weeks or even months as some epoxies and “first generation” UV adhesives complete their cure cycles.
New technology DYMAX Optical Adhesives that are designed to minimize stress while producing durable bond. Effect of stress and temperature on the optical phonons of aramid ﬁbers D. Bollas, 1,2J. Parthenios, and C. Galiotis1,2,3,* 1Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes, Greece 2Inter-Departmental Programme of Graduate Studies in Polymer Science and .
Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light.
These optically anisotropic materials are said to be birefringent (or birefractive). Jul 12, · Deformed mesh in Stress-Optical Effects. Posted Jul 11, , AM PDT RF & Microwave Engineering, Mesh, Structural Mechanics & Thermal Stresses 1 Reply.
E. H. Send Private Message Report. Please login with a confirmed email address before reporting spam These days I am also working on the stress-optical effect.
But I met problems. Relative Stress-Optical Coefficients of Some National Bureau of Standards The stress-optical coeffi cients determined fo r the croll'n glasses ranged between and + brewsters.
For the fli nt glasses, a regular vari ation of the stress-opticttl The efFect of tbe chemical composition of glass on.
The optical band gap and the ultraviolet emission peak of the films is found to shift to smaller values with the increase in the growth temperature, which shows a correlation in the optical band gap and the stress present in the film.