We report on a wavelength division multiplexed-orthogonal frequency division multiplexed-passive optical network (WDM-OFDM-PON), for downstream transmission, based on a tunable mode locked comb source. The 12.75 Gb/s compatible single side-band (SSB) OFDM signal is used to modulate 10 comb tones separated by 10 GHz. Net spectral efficiencies of 1.12 and 1 bit/s/Hz were achieved in conjunction with the use of low complexity electronics. Transmission over 50 and 87 km of standard single mode fiber was successfully demonstrated. The incurred penalty after transmission over 50 km was <1 dB at a bit error rate (BER) of 3 × 10-3, relative to the back-to-back case. All channels after 87 km transmission achieved performance below the 20% forward error correction (FEC) limit. © 1989-2012 IEEE.