Reusable polymer optical fiber strain sensor with memory capability based on ABS crazing.

A reusable memory capable polymer optical fiber (POF) strain sensor is reported. The fiber consists of an acrylonitrile butadiene styrene (ABS) core and polymethylmethacrylate cladding. The memory capability is derived from stress whitening due to crazing of the ABS core, which can be reversed by heating the fiber close to the ABS glass transition temperature. The probe was characterized under transverse compressive load, macrobending, and tensile loading. Testing shows that the optical properties of the fiber can be reversed to near pristine ABS conditions after thermal recovery and that the POF can be used on the accurate assessment of indentation, flexural and tensile loading, static or cyclical, even after removal of the load. The reusability of the proposed sensor combined with a deeper understanding of the memory mechanisms in POFs are of great interest for the development of new large-strain sensors for modern applications.

Ultra-simplified Single-Step Fabrication of Microstructured Optical Fiber.

Manufacturing optical fibers with a microstructured cross-section relies on the production of a fiber preform in a multiple-stage procedure, and drawing of the preform to fiber. These processes encompass the use of several dedicated and sophisticated equipment, including a fiber drawing tower. Here we demonstrate the use of a commercial table-top low-cost filament extruder to produce optical fibers with complex microstructure in a single step - from the pellets of the optical material directly to the final fiber. The process does not include the use of an optical fiber drawing tower and is time, electrical power, and floor space efficient. Different fiber geometries (hexagonal-lattice solid core, suspended core and hollow core) were successfully fabricated and their geometries evaluated. Air guidance in a wavelength range where the fiber material is opaque was shown in the hollow core fiber.