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We have fabricated the first single-mode step-index and humidity insensitive polymer optical fiber operating in the 850 nm wavelength ranges. The step-index preform is fabricated using injection molding, which is an efficient method for cost effective, flexible and fast preparation of the fiber preform. The fabricated single-mode step-index (SI) polymer optical fiber (POF) has a 4.8µm core made from TOPAS grade 5013S-04 with a glass transition temperature of 134°C and a 150 µm cladding made from ZEONEX grade 480R with a glass transition temperature of 138°C. The key advantages of the proposed SIPOF are low water absorption, high operating temperature and chemical inertness to acids and bases and many polar solvents as compared to the conventional poly-methyl-methacrylate (PMMA) and polystyrene based POFs. In addition, the fiber Bragg grating writing time is short compared to microstructured POFs.
We report the fabrication and characterization of a polycarbonate (PC) microstructured polymer optical fiber (mPOF) Bragg grating (FBG) humidity sensor that can operate beyond 100ºC. The PC preform, from which the fiber was drawn, was produced using an improved casting approach to reduce the attenuation of the fiber. The fiber loss was found reduced by a factor of two compared to the latest reported PC mPOF [20], holding the low loss record in PC based fibers. PC mPOFBG was characterized to humidity and temperature, and a relative humidity (RH) sensitivity of 7.31±0.13 pm/% RH in the range 10-90% RH at 100ºC and a temperature sensitivity of 25.86±0.63 pm/ºC in the range 20-100 ºC at 90% RH were measured.
We describe an automatic system for fast unattended acquisition of accurate and complete 3D models, called Ro-boScan. The design goal is to reduce the three main bottlenecks in human-assisted 3D scanning: the selection of the range maps to be taken (view planning), the positioning of the scanner in the environment, and the range maps' alignment. The system is designed around a commercial laser-based 3D scanner moved by a robotic arm. The acquisition session is organised in two stages. First, an initial sampling of the surface is performed by the automatic selection of a set of views. Then, some added views are automatically selected, acquired and merged to the initial set in order to fill the surface regions left unsampled. Both the initial set of range maps and the subsequently added ones are post-processed automatically, by using the known scanner positions to initialise the alignment phase. Results of the assessment of the system on real acquisitions are presented and discussed.
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