OFDM-NOMA Optical Transmission Utilizing Dispersion-Induced Power Fading of SMF for Multi-Distance PON

We propose a novel optical transmission technique based on orthogonal frequency division multiplexing non-orthogonal multiples access (OFDM-NOMA) for multi-distance passive optical network with direct detection. This method uses diversity of dispersion-induced power fading in single-mode fiber channels to suppress the interference caused by non-orthogonally multiplexed OFDM. Since chromatic dispersion in optical fiber involves the conversion between optical intensity and phase modulations, an arbitrary frequency can be suppressed at a specific transmission distance by adjusting the intensity-to-phase modulation ratio at the transmitter. In the proposed technique, two optical signals are polarization-multiplexed to suppress the NOMA frequency band across different transmission distances. As chromatic dispersion suppresses interference between NOMA signals, direct detection using a single photodetector is possible without polarization demultiplexing and successive interference cancellation. 23 and 43 km transmission of 8 Gb/s polarization-multiplexed OFDM-NOMA was performed and successfully verified the proposed technique.