Patent ID: 8849119

Claim:
A wavelength-shifted bidirectional wavelength division multiplexing (WDM) optical network comprising: an optical fiber line; an optical line terminal (OLT) comprising a first optical transmitter transmitting a downstream WDM optical signal, a first standard wavelength multiplexer/demultiplexer that wavelength-multiplexes the downstream WDM optical signal, a first optical circulator transferring the wavelength-multiplexed downstream WDM optical signal through the optical fiber line, and transferring a wavelength-multiplexed upstream WDM optical signal transferred through the optical fiber line, a first wavelength-shifted wavelength multiplexer/demultiplexer that wavelength-demultiplexes the wavelength-multiplexed upstream WDM optical signal transferred through the first optical circulator to form a wavelength-demultiplexed upstream WDM optical signal, and a first optical receiver receiving the wavelength-demultiplexed upstream WDM optical signal; a remote node (RN) comprising a second wavelength-shifted wavelength multiplexer/demultiplexer shifting a center wavelength of an upstream WDM optical signal, and wavelength-multiplexing the upstream WDM optical signal with the shifted center wavelength to form the wavelength-multiplexed upstream WDM optical signal, a second optical circulator transferring the wavelength-multiplexed upstream WDM optical signal through the optical fiber line, and transferring the wavelength-multiplexed downstream WDM optical signal transferred through the optical fiber line, and a second standard wavelength multiplexer/demultiplexer that wavelength-demultiplexes the wavelength-multiplexed downstream WDM optical signal transferred through the second optical circulator to form a wavelength-demultiplexed downstream WDM optical signal; and multiple optical network units (ONUs) each comprising a second optical transmitter transmitting the upstream WDM optical signal to the second wavelength-shifted wavelength multiplexer/demultiplexer, and a second optical receiver receiving the wavelength-demultiplexed downstream WDM optical signal.