摘要 |
MULTIFILAMENT TYPE PLASTIC OPTICAL FIBER AND PROCESS FOR PREPARATION THEREOF A multifilament type plastic optical fiber having a substantially rectangular cross-section and an islandsin-the-sea structure in which 100 to 10,000 islands are arranged in the sea, wherein the respective islands have a substantially circular cross-section and a core-sheath structure, the islands are arranged in a sigzag-stacked structure, the core occupancy ratio in the multifilament type optical fiber cores section is at least 50% and the brightness index value I which is defined by the following (1), is at least 4.5 x 10-2: I = S?NA2?10 (1) wherein S stands for the core occupancy ratio in the multifilament type optical fiber, .alpha. stands for the transmission loss (dB/m) per meter of the multifilament type optical fiber, NA stands for the numeral apertures, and L stands for the length (m) of the used optical fiber. |