Using adaptive four-band OFDM modulation with 40 Gb/s downstream and 10 Gb/s upstream signals for next generation long-reach PON.

In this demonstration, we propose and demonstrate an adaptive long-reach passive optical network (LR-PON) using four-band orthogonal frequency division multiplexed (OFDM) channels. The downstream traffic rates from 6.25 to 40 Gb/s (using fixed quadrature amplitude modulation (QAM) level in the four OFDM bands) and from 9.37 to 40.3 Gb/s (using variable QAM levels in the four OFDM bands) can be achieved adaptively in the optical network units (ONUs) depending on different fiber transmission lengths from 0 to 100 km. For the upstream transmission, a 10 Gb/s 16-QAM OFDM signal with pre-emphasis is experimentally performed by using a 2.5 GHz directly modulated laser (DML). Based on the simulation and experimental results, the proposed adaptive four-band OFDM system could be a promising candidate for the future LR-PON.