Recent status of the polymer optical fiber (POF) for high-speed data communication and telecommunication is reviewed. The GI POF was proposed for the first time at Keio University, and several methodologies to fabricate GI POF have been currently proposed. In this paper, we clarify the great advantage of perfluorinated polymer as the polymer matrix of low-loss and high bandwdith graded-index (GI) POF It is generally known that the PF polymer can decrease the intrinsic absorption loss compared with poly methy methacrylate (PMMA), which is the conventional material of POF Furthermode, it was found that low material dispersion of the PF polymer is another advantage to obtaind the high bandwidth GI POF It was clarified for the first time that the power distribution of modes formed by the mode dependent attenuation was the dominant factors of the higher bandwidth of the GI POF than theoretically predicted bandwidth, while the effect of the mode coupling was small.