System and method for communication via an optical link and associated relay terminal

Relay terminal (4; 62) which is intended to communicate over an optical link comprising a first user terminal (6) and a second user terminal (8); wherein the first user terminal (6) is adapted to a beam in a first spectral band (B1) to the relay terminal (4; 62) to be transmitted, and wherein the second user terminal (8) is adapted to (a beam in a second spectral band B2) extending (from the first spectral band B1) is different (on the relay terminal 4, to transmit 62); characterized in that the relay terminal (4; 62) comprises: - a first communication path (30; 64) which is adapted to process the beams to the first spectral band (B1) include, - a second communication path (32; 72) which is adapted to process the beams to the second spectral band (B2) include, wherein the first spectral band (B1) and the second spectral band (B2) of between 0.7 microns and 1 , are 7 micrometers; wherein the first spectral band (B1) and the second spectral band (B2) are separated by a spectral distance of more than 0.1 microns; and - a transfer unit (22), comprising: - a receiving element (37) which is adapted to come at least a portion of the beam from the first user terminal (6) and at least a portion of the beam coming from the second user terminal (8) to receive, and - a control / regulating element (36, 38) is adapted during the whole duration of the communication received the part of the energy of the of the receiving element (37) beam in the first spectral band (B1) is contained, to the first communication path (30; 64) to be transferred and the remainder of the energy of the of the receiving member (37) received beam to the second communication path (32; 72) to be transmitted.