Patent ID: 6922431

Claim:
A method of transferring an electrical digital signal from a first terminal on an optical fiber to a second terminal, the electrical digital signal incoming to the first terminal, the method comprising the sequential steps of: spreading the electrical digital signal using a spread spectrum method to produce a spread electrical signal; modulating the spread electrical signal on a subcarrier of a radio frequency to produce a modulated electrical signal of a first frequency range around the radio frequency of the subcarrier; adding a control digital signal of a second frequency range comprising control information to the modulated electrical signal to provide a sum signal, frequencies of the first frequency range being higher than frequencies of the second frequency range; converting the sum signal to an optical signal; transmitting the optical signal on the optical fiber to the second terminal to be received in the second terminal as a received optical signal; and performing in the second terminal inverse operations on the received optical signal to provide signals corresponding to the electrical digital signal and to the control digital signal.