Full duplex optical modem for broadband access network

Abstract

An optical modem link for full duplex transmission of multiple, independent RF carrier signals between network elements of a Broadband Access Network, includes a first optical modem, e.g., at a CATV headend broadcast facility, linked by a single optical fiber with a second optical modem, e.g., at a distributed hub location, to form an optical modem link. Each optical modem end of a respective link is equipped with an optical transmitter, which transmits light signal having a first wavelength, a receiver which receives a light signal having a second wavelength, and a wavelength division multiplexer which directs the outgoing light signal onto, and the incoming light signal off of, respectively, the fiber link. Simultaneous transmission of digital baseband signals and independent RF signals in each direction over the optical modem link is accomplished by first forming an aggregate digital data signal from the digital baseband data signals to be transmitted, modulating an RF carrier with the aggregate digital data signal, and modulating an optical signal with both the digitally modulated RF carrier signal and the independent RF signals, respectively, so that all communication signals are transmitted in the RF domain over the optical link.