Orthogonal Frequency Division Multiplexing (OFDM) has gained great attention in the next generation Long-Reach Passive Optical Network (LR-PON) due to its high spectrum efficiency, flexible resource allocation and natural compatibility with Digital Signal Processing (DSP)-based implementation. In this paper, we propose and demonstrate a 40Gbit/s direct-detection long reach OFDM-PON system for downstream transmission over 100km standard signal mode fiber (SSMF). By using a simple Least Square (LS) method for the channel estimation, our proposed system achieves high bit rate without the need for chromatic dispersion compensation.
