Patent ID: 9749080
Date: 2017-08-29
CPC Classifications: H04B,H04J,H04Q

Claim:
1. A communication system comprising: a central office comprising: a feeder optical fiber optically connected with the third multiplexer and arranged to convey the feeder optical signal; and an arrayed waveguide grating optically connected with the feeder optical fiber and configured to multiplex/demultiplex between the feeder optical signal and optical network unit signals, each optical network unit signal comprising a legacy upstream wavelength in a legacy upstream free spectral range, a legacy downstream wavelength in a legacy downstream free spectral range, an upgrade upstream wavelength in an upgrade upstream free spectral range, and an upgrade downstream wavelength in an upgrade downstream free spectral range, wherein each of the first and second optical line terminal signals comprises the legacy downstream wavelength in the legacy downstream free spectral range, each of the third and fourth optical line terminal signals comprises the legacy upstream wavelength in the legacy upstream free spectral range, each of the fifth and sixth optical line terminal signals comprises the upgrade downstream wavelength in the upgrade downstream free spectral range, and each of the seventh and eighth optical line terminal signals comprises the upgrade upstream wavelength in the upgrade upstream free spectral range.