Single channel 224 Gbit/s (56-GBaud) PAM-16 transmission using linear digital pre-distortion

摘要： With linear digital pre-distortion (DPD) and 8-bit digital to analogue converter (DAC), a single channel 224 Gbit/s (56-GBaud) 16-level pulse amplitude modulation (PAM-16) signal is experimentally transmitted over a 100 m standard single-mode fibre (SSMF) for the first time using intensity modulation and direct detection (IM/DD). The 3 dB bandwidth of the whole system is around 22 GHz, which is far below the bandwidth of the 56-GBuad PAM-16 signal. The strong inter-symbol interference caused by the limited system bandwidth is pre-compensated by the proposed linear DPD technique. The experimental results indicate that the linear DPD process can effectively avoid the noise enhancement by the aggressive feed-forward equalisation at the receiver, and also improves the system performance at the cost of additional finite impulse response filter at the transmitter.