Optical fiber, optical fiber ribbon and optical fiber cables

A optical fiber to reduce the reduced and strength reduction increase of transmission loss, to provide an optical fiber ribbon and optical fiber cables. SOLUTION: In an optical fiber the primary coating layer on an outer peripheral surface of the optical fiber is coated, wherein the primary coating layer comprises a UV-curable resin, the ultraviolet curable resin, a reactive silane coupling agent wherein at least 0.05 part by weight and 0.75 parts by mass, to provide an optical fiber which comprises a non-reactive silane coupling agent 0.05 parts by mass or more and 0.75 parts by mass. .FIELD 1A