A process to enhance the performance of plastic optical fiber to operate with a high data rate (e.g., at least 1 gigabit per second) at high temperature (e.g., 100 degrees Celsius) for airplane avionic systems. Gigabit plastic optical fiber has a core including a dopant that enables data transmission at gigabit rates. The enhancement process uses rapid thermal cooling of the gigabit plastic optical fiber to stabilize the polymer matrix of the fiber. This rapid cooling treatment blocks dopant diffusion in a high-temperature environment, thereby avoiding degradation of the fiber's bandwidth and optical loss characteristic. Such degradation typically occurs in gigabit plastic optical fiber having core and cladding made of transparent carbon-hydrogen bond-free perfluorinated polymer.