PLASTIC OPTICAL FIBER, PLASTIC OPTICAL CABLE, AND OPTICAL SIGNAL TRANSMISSION METHOD

摘要

PROBLEM TO BE SOLVED: To broaden a transmission band while suppressing increase of transmission loss and bending loss in a step index type plastic optical fiber. SOLUTION: The optical fiber which consists of the plastics material has a core 10, and one or more optical transmission parts 20 consisting of two or more sheath layers 11a and 11b provided at the circumference of the core 10, and is provided with one or more protective layers 12 at the circumference of the optical transmission parts 20. The refractive index of the first sheath layer 11a at the innermost part of sheath layers 11a and 11b is lower than the refractive index of the core 10. The refractive index of the sheath layer 11b provided outside the first sheath layer 11a is equal to or more than the refractive index of the first sheath layer 11a, and the refractive index of the innermost protective layer 12 is lower than the refractive index of the outermost sheath layer 11b.