All-polymer multimaterial optical fiber fabrication for high temperature applications

In this work, we report the fabrication of an all-polymer multimaterial optical fiber based on two different grades of cyclo-olefin polymers (known as Zeonex) and the highperformance thermoplastic polysulfone (PSU) with glass transition temperature (T_g) of 189°C. The core/cladding structure using the Zeonex polymers (E48R/480R, respectively) was developed using a co-extrusion method followed by a rod-in-tube approach to form the final preform. The fiber materials were characterized in terms of their T_g, viscosity as well as refractive index profiles. The final preform was thermally drawn down to a fiber with ~300 μm and ~70 μm total and core diameter, respectively. We thermally characterized and compared our step-index fiber with a commercially available polymer (Cytop) as well as a purely Zeonex single-mode step-index fiber. The proposed multimaterial fiber exhibited stable operation at temperatures as high as 180°C being ~35°C higher than any polymer fiber reported so far to the best of our knowledge. Therefore, we believe that our results constitute a significant step forward for the polymer optical fiber community making the proposed polymer multimaterial fiber an efficient route towards truly heat-resistant applications.