High temperature resistant graded-index polymer optical fiber

The dopant system graded-index polymer optical fiber (GI POF) for high temperature stability both in bandwidth and attenuation is reported for the first time. We confirmed that the numerical aperture (NA) of the GI POF strongly influences the high temperature stability of the GI POF in the attenuation. It was confirmed in this paper that the attenuation increment was mainly induced by the bending loss, since the GI POF drawn by high tension tended to show its length shrinkage, resulting in irregular bending due to the orientation relaxation of polymer chain. We clarified the optimum drawing tension which maintains high mechanical property and minimizes the length shrinkage of the GI POF at high temperature, and the optimum fabrication conditions of the GI POF for high temperature stability both in bandwidth and attenuation.