The channel estimation result of non-pilot subcarriers mainly depends on adjacent pilot subcarriers. A linear interpolation algorithm has been applied to the channel estimation of non-pilot subcarriers. The performance of interpolation algorithm has been simulated in a 10Gb/s direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) communication system. Constellation convergence is greatly improved.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.