Passive optical network system and optical signal receiving method thereof

A method for receiving upstream optical signals from a plurality of optical network units in a passive optical network system, the method comprising:

• overlapping and multiplexing a plurality of upstream optical signals having different wavelengths;
• and
• receiving, by an optical line terminal, the multiplexed upstream optical signals divided in a time division multiplexing (TDM) scheme,
• wherein the multiplexed upstream optical signals are divided according to the different wavelengths, and the upstream optical signals corresponding to the divided wavelengths are received through a plurality of optical receivers, and
• wherein the upstream optical signals of the same wavelengths received by any one of the optical receivers are divided in a time division multiplexing (TDM) scheme.

A passive optical network system, comprising:

• a plurality of optical signal splitter receiving optical signals from a plurality of optical network units (ONUs) to provide a plurality of upstream optical signals having different wavelengths;
• a hybrid optical filter multiplexing the plurality of upstream optical signals in a wavelength division multiplexing (WDM) scheme;
• and
• an optical line terminal (OLT) receiving the multiplexed upstream optical signals in a time division multiplexing (TDM) scheme,
• wherein the hybrid optical filter comprises:
• a plurality of optical signal dividers and a mirror dividing a downstream optical signal to different input ports, and a plurality of wavelength filters overlapping the plurality of upstream optical signals to one position through a plurality of filters, the plurality of wavelength filters being arranged to have minimum number of transmission with respect to the plurality of upstream optical signals.