Modal bandwidth enhancement in a plastic optical fiber by W-refractive index profile

A plastic optical fiber (POF) having a W-shaped refractive index profile (W-shaped POF) was prepared for the first time that had a possibility to realize a higher bit rate transmission than those of the conventional silica-based multimode fiber and graded index (GI) POF links. Since the W-shaped POF has a valley of the refractive index at the boundary of the core and cladding of the conventional graded-index (GI) POF, the group delay of higher order modes is strongly influenced, and the modal dispersion in the GI POF is compensated. By comparing the propagating mode properties of the W-shaped POF with those of the GI POF, we clarified theoretically and experimentally that the index valley has a remarkable modal dispersion compensation effect.