High-temperature polymer multimaterial fibers

This work presents the fabrication of a heat-resistant multimaterial polymer optical fiber based on two different grades of cyclo-olefin polymers (Zeonex grade E48R and 480R) and high-performance thermoplastic polysulfone (PSU) [1] . The latter are known mainly for their high heat resistance (> 190 o C), strength, durability, biocompatibility, as well as their ability to withstand several cycles and doses of radiation [2] . POFs have distinct advantages compared to silica fibers, however their main limitation is that they cannot operate at high temperatures due to the low Tg of the host material [3] . Our three polymer materials are characterized using a Dynamical Mechanical Thermal Analysis (DMTA) where the glass transition temperatures of the materials are identified as shown in Fig. 1 (a) . We measured T g =143.1 o C and T g =143.2 o C for the 480R and E48R, respectively, and a T g =189 o C for the PSU. The core/cladding structure of our multimaterial fiber consist of Zeonex grade E48R and 480R and was developed using a co-extrusion method followed by a rod-in tube approach to form the final preform, as shown in Fig. 1 (b) . The drawn multimaterial fiber exhibited ~300 μm and ~70 μm total and core diameter, respectively. The transmission spectrum and the optical losses were then measured for the multimaterial POF as shown in Fig. 1 (c) , showing a minimum loss of ~13.9 dB/m at 800 nm, higher than previous reported [4] . Finally, we thermally characterized and compared our multimaterial POF with a commercially available Cytop fiber as well as a purely Zeonex step-index fiber, as depicted in Fig. 1 (d) . Our proposed multimaterial POF exhibited stable output power for several hours at 180 o C, which is higher than any polymer fiber reported so far.