Deep photonic reservoir computer for fiber nonlinearity compensation of coherent signals

This work experimentally demonstrates a fiber nonlinearity compensation technique by using the deep photonic reservoir computer (PRC). The deep PRC is constructed by cascading injection-locked semiconductor lasers with optical feedback. The deep PRC has 3 reservoir layers and a total of 120 virtual neurons. The operation frequency of the deep PRCis as high as 20 GHz. The signal under processing is a 240 Gbps 16-QAM coherent signal, with a launch power of 12 dBm and a transmission distance of 50 km. It is experimentally proved that the deep PRC achieves a Q-factor gain as high as 0.58 dB, compared with the conventional digital signal processing technique.