Orthogonal frequency division multiple access PON (OFDMA PON) employs orthogonal frequency division multiplexing (OFDM) as the data modulation scheme to increase the provisioning data rate. Qian et al.  demonstrated the transmission of 108 Gb/s downstream data rate over a type B fiber with a split ratio of 32. Figure 6.1 describes one typical OFDMA PON architecture. OFDMA PON uses OFDMA as an access scheme [90, 111], which divides the upstream/downstream bandwidth in baseband into multiple subcarriers with orthogonal frequencies. These subcarriers are dynamically allocated to different ONUs based on their real-time incoming traffic information. As compared to TDM PON and WDM PON, OFDMA PON enjoys numerous advantages such as high speed transmission, fine granularity of bandwidth allocation, and color-free ONUs .