The uplink physical throughput potential of orthogonal frequency division multiplexing passive optical network (OFDM-PON) is discussed. Reflective semiconductor optical amplifiers (RSOAs) are used in optical network units (ONUs) as the colorless resources to produce the dual-sideband intensity modulation, and a PIN photodiode with semiconductor optical amplifier (SOA) as pre-amplifier is used in optical line terminal (OLT) to complete direct detection. Based on a coherent narrowband integral model of RSOA, the weak perturbation solutions of the carrier rate equation and the wave propagation equation are used to investigate the RSOA’s dynamic electro-optical modulation behavior and frequency chirp characteristic theoretically and experimentally. It is proved that the RSOA is of low-pass modulation characteristics, and its 3 dB cut-off frequency is related to the bias current and the inject optical power. The optical equilibrium is achieved and the 3 dB cut-off frequency of the uplink can be promoted from 1.5 GHz up to 2.2 GHz by taking advantage of RSOA’s optical frequency chirp and the high-pass optical gain characteristic of SOA, and cascading a blue-shifted optical band-pass filter with RSOA. Furthermore, by utilizing the adaptive bit loading modulation, the data throughput in one RSOA-based uplink can reach 4 Gb/s and above，which means that the total uplink throughput of an OFDM-PON with ten RSOA-based ONUs can achieve 40 Gb/s.