Channel Estimation Algorithms in Optical OFDM Transmission

Recent progress and patents on channel estimation algorithms in optical orthogonal frequency division multiplexing (OFDM) systems are reviewed. The channel estimation algorithms can be divided into two categories of pilotaided and blind approaches. For the pilot-aided schemes, the two pilot patterns including the comb-type pilots and blocktype pilots are evaluated by experiments. For the blind schemes, the phase noise caused by the laser linewidth and chromatic dispersion (CD) in the fiber channel can be effectively compensated by the proposed data-aided channel estimation algorithms, which is experimentally demonstrated by the significant improvement in the performances of transmitted OFDM signals.