Polymeric optical fibers and preform manufacture

Abstract

This Master of Science Thesis is one part of the project to set up development work of polymeric optical fibres (POF) in the Institute of Fibre Materials Science at Tampere University of Technology. The aim of this study was description of polymers in POF applications and fabrication of an optical fibre preform. The properties of plastics offer possibilities for various applications to the optical fiber field. POFs connect cost effectively different interconnections. The main transparent polymers for optical applications are polymethyl methacrylate, polycarbonate, polystyrene, and cyclic olefin copolymers. Perfluoro polymers with a remarkable lower attenuation than the other polymers are attractive for LAN applications. However, the cost of the material is high. The experiments concentrated on PMMA chemistry. Optimal level of process conditions to attain desired molecule construction of the polymer was evaluated by polymerisation tests, which were analysed with GPC. Based on the results of the tests thermal bulk polymerisation is a robust method of MMA polymerisarion. Models of molecule weight and intrinsic viscosity as a function of the content of the initiator and the chain transfer agent were developed. A step index perform with a homogeneous core region of constant refractive index surrounded by a cladding polymer of lower refractive index was fabricated. The core of the perform was cast after formation of the cladding. Equipments used were perform lathe and nitrogen pressurized (25bar) reactor. The polymerisation was carried out at 90°C and the polymerisation time used is 24 h. /Kir10