The purpose of this article is to study the materials physics behind dye-doped polymethyl metharcylate (PMMA) that is important for the optical fiber drawing process. We report effects of the fabrication process on the mechanical properties of the final fiber. The qualitative degree of polymer chain alignment is found to increase with the drawing force, which in turn decreases with the drawing temperature and increases with the drawing ratio. The chain alignment relaxes when the fibers are annealed at 95 °C with a commensurate decrease in fiber length and increase in diameter. The annealed fiber has higher ductility but lower strength than the unannealed fiber. Both the yield and tensile strengths are dependent on the strain rate. The relationship between tensile strength, σb, and fiber diameter, d, is found empirically to be σb∝d−0.5. The yield strength appears to be less sensitive to the fiber diameter than the tensile strength. For PMMA doped with disperse red 1 azo dye, the yield strength, tensile strength, and Young’s modulus peak at a dye concentration of 0.0094 wt %. These results are useful for designing polymer optical fibers with well-defined mechanical properties.
We report on the demonstration of an all-optical feedback circuit that photomechanically stabilizes the length of a polymer-optical fiber through a photothermal mechanism.
We report on the demonstration of all-optical switching in a 110 μm diam, 1 cm long Fabry–Perot cavity defined in a dye-doped polymer optical fiber waveguide. Such a device is a basic building block of optical logic.
In previous studies, we demonstrated the ability to linearly guide axonal regeneration using scaffolds comprised of precision microchannels 2 mm in length. In this work, we report our efforts to augment the manufacturing process to achieve clinically relevant scaffold dimensions in the centimeter-scale range. By selective etching of multi-component fiber bundles, agarose hydrogel scaffolds with highly ordered, close-packed arrays of microchannels, ranging from 172 to 320 μm, were fabricated with overall dimensions approaching clinically relevant length scales. Cross-sectional analyses determined that the maximum microchannel volume per unit volume of scaffold approached 80%, which is nearly twice that compared to our previously reported study. Statistical analyses at various points along the length of the microchannels also show a significant degree of linearity along the entire length of the scaffold. Two types of multi-component fiber bundle templates were evaluated; polystyrene and poly(methyl methacrylate). The scaffolds consisting of 2 cm long microchannels were fabricated with the poly(methyl methacrylate) fiber-cores exhibited a higher degree of linearity compared to those fabricated using polystyrene fibers. It is believed that the materials process developed in this study is useful for fabricating high aspect ratio microchannels in biocompatible materials with a wide range of geometries for guiding nerve regeneration.
We report on the demonstration of both mechanical and optical multistability in a 110 μm diameter and 2.5 cm long Fabry-Perot cavity defined in a dye-doped polymer optical fiber waveguide. Such a device is a basic building block of optical and mechanical logic.
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