FREE-SPACE OPTICAL RECEIVER, FREE-SPACE OPTICAL COMMUNICATION SYSTEM, AND FREE-SPACE OPTICAL COMMUNICATION METHOD

摘要

It is difficult to increase the transmission rate in free-space optical communication systems due to the fact that deterioration of the coupling efficiency between received light and single-mode fiber cannot be avoided. For this reason, the present invention provides a free-space optical receiver comprising: a light-collecting means which collects reception-side laser light that has been propagated through a free-space transmission path and subjected to wavelength multiplexing; an excitation mode control means into which reception-side laser light collected by the light-collecting means is input, which generates a propagation mode group comprising a plurality of types of propagation mode light in which the excitation state differs for each wavelength, and which separates each of the plurality of types of propagation mode light and outputs the resu a plurality of single-mode transmission mediums which guide each of the plurality of types of propagation mode light; and a plurality of light-receiving means which receive each of the plurality of types of propagation mode light via the plurality of single-mode transmission mediums.