OPTIMIZATION OF THE REFRACTIVE-INDEX DISTRIBUTION OF HIGH-BANDWIDTH GI POLYMER OPTICAL-FIBER BASED ON BOTH MODAL AND MATERIAL DISPERSIONS

The optimum refractive-index distribution of the high bandwidth graded -index polymer optical fiber (GI POF) in which material dispersion is taken into account was clarified for the first time. Since modal dispe rsion remarkably decreases by GI POF, this paper focuses on the ultima te bandwidth achieved by POF, quantitatively estimating the material d ispersion as well as modal dispersion. The results indicated that the bandwidth of the poly(methyl methacrylate) (PMMA) based GI POF was dom inated by material dispersion when the required data rate becomes larg er than a few Gbs(-1). It was also confirmed that material dispersion strongly depends on the matrix polymer and that use of fluorinated pol ymer whose material dispersion (-0.078 ns nm(-1) km(-1)) is lower than that of PMMA (-0.305 ns nm(-1) km(-1)) allows for a 10 Gbs(-1) signal transmission.