A novel smooth PON evolution based on signal cancellation

Abstract

A novel smooth evolution from current PONs to next generation PON is proposed. The new PON link is added into the deployed optical distribution network to reuse the existing infrastructure. Pre-cancellation is applied to eliminate the crosstalk from the new PON signal to the legacy PON signal. In the optical line terminator (OLT), the legacy PON signal is added with an inverse new PON signal before optical modulation. The optical signal from the legacy PON transmitter is the sum of the legacy PON signal and the inverse new PON signal. Such optical signal will be received together with new PON optical signal in the existing optical network units (ONUs). The added inverse new PON signal cancels the received new PON signal, with the legacy PON signal left. Compared with the previous coding based smooth evolution, the effective bit rate of the new PON signal is higher as the code efficiency is 100% and the operation complexity is lower as coding and decoding are not required. The signal cancellation based smooth evolution from 1.25 Gb/s, 2.5 Gb/s, and 10 Gb/s legacy PON to 10 Gb/s new generation PON is demonstrated. The tested results show the feasibility of the proposed smooth evolution.