Patent ID: 8538259

Claim:
An optical access network system comprising a relay station that receives a wavelength multiplexed optical signal (WDM optical signal) from an optical network, and transmits optical signals having specified wavelengths to subscriber units, wherein said relay station comprises: optical demultiplexing means for demultiplexing said WDM optical signal into a plurality of optical signals having fixed wavelength intervals between them as one group; optical branching means for dividing the demultiplexed group of optical signals into a plurality of branches; and switching means for transmitting the divided group of optical signals to specified subscriber units, wherein said optical demultiplexing means is a cyclic multiplexing/demultiplexing filter that demultiplexes each of the optical signals of a plurality of groups from said WDM optical signal, and multiplexes the optical signals of each group, then outputs the signal from a specified port; and said relay station comprises a said optical branching means and optical switching means for each group.