Employing feed-forward downstream cancellation in optical network units for 2.5G/1.25G RSOA-based and 10G/10G REAM-based Passive Optical Networks for efficient wavelength reuse

Optical Network Units for Next-Generation Passive Optical Networks with wavelength reuse are investigated for asymmetrical 2.5 G/1.25 G and symmetrical 10 G/10 G down- and upstream data rates. The transmission performance was enhanced by a feed-forward cancellation circuitry adapted to an RSOA and an REAM used as remodulator. The range of downstream extinction ratios for error-free upstream transmission at BER of 10
^-10
was extended from 3 to 4 dB for the RSOA-based ONU and from 1.5 to 3 dB for the REAM-based ONU.