OPTICAL TRANSMISSION SYSTEM, OPTICAL TRANSMISSION PATH, AND OPTICAL-ELECTRICAL COMPOSITE CABLE

An optical transmission system includes an optical signal transmitter that transmits an optical signal output from a light source, an optical signal receiver that receives the optical signal, and an optical transmission path that optically connects the optical signal transmitter and the optical signal receiver and transmits the optical signal, wherein a first optical transmission path is disposed immediately after the light source and further, optically connected to a second optical transmission path, the first optical transmission path having a product of a scattering loss with respect to the optical signal and a length of 6 dB or less, and when a Gaussian beam emitted from a single-mode optical fiber is input by center excitation, the first optical transmission path outputting the Gaussian beam with a beam diameter being enlarged by three times or more.