A system for transmitting a message from a source entity to a target entity, the system including an input unit connected to the source entity in order to transmit the message via an optical transmission device to an output unit re-directing the message to the target entity. The optical transmission device is configured to transmit the message unidirectionally from the input unit to the output unit; and duplicate an optical input system containing the message into at least two optical output signals each containing the message to be transmitted to the output unit.