OPTICAL FIBER, METHOD FOR MANUFACTURING OPTICAL FIBER, OPTICAL FIBER CABLE, AND SENSOR

摘要

The present invention provides a plastic optical fiber having a core and cladding comprising at least one layer, the plastic optical fiber having a transmission loss of 120dB/km or less as measured by a 25m-1m cutback technique under the conditions of a wavelength of 525nm and excitation NA=0.45, and satisfying either one of the following conditions when the thickness of the innermost cladding layer is 0.5µm - 4.5µm: the concentration of foreign matter having a size of 2µm or greater contained in the innermost cladding layer is 2000/cm3 or less, or a size X (µm) of the foreign matter contained in the innermost cladding layer and the amount Y of the foreign matter (number/cm3) satisfy formula (1) below: Y ≤ 1200 × e(-0.067×X). Such optical fibers have a low transmission loss of green light (in particular, light having a wavelength of 525nm), enabling longer distance communication.