Slow Adaptive OFDMA-PON Through Channel Stabilization Employing Seed Carrier Clipping

We have proposed and experimentally demonstrated a novel slow adaptive orthogonal frequency division multiple access (OFDMA)-based passive optical network (PON) with a single-fiber loopback link. The proposed slow adaptive OFDMA-PON is realized by employing a clipping modulation of an optical seed carrier, which is fed to uplink transmitters at an optical network unit (ONU) in a carrier distribution scheme. Therefore, a fast changing characteristic of the single-fiber loopback channel, which is mainly attributed to Rayleigh backscattering interference, can be dramatically stabilized. Consequently, the uplink OFDMA-PON transmitters can reduce a large number of signal processing in updating channel state information and relevant subcarrier allocation for multiple access unless the required traffic condition changes for the given ONU.