2025/04/23 by Li, Rui-Qian, Shen, Yi-Wei, Niu, Zekun +5
#FOS: Physical sciences #Optics (physics.optics)
paper · doi:10.48550/arxiv.2504.16769
Photonic reservoir computer (PRC) is a kind of real-time and adaptive recurrent neural network, where only weights in the readout layer require training. PRC is a promising tool to deal with the crucial issue of nonlinear equalization in optical fiber communications. Here we theoretically show a deep PRC for the nonlinear equalization of coherent signals with the format of 16- level quadrature amplitude modulation (16-QAM). The deep PRC consists of cascading injection-locked Fabry-Perot lasers with optical feedback. Both the in-phase component and the quadrature component of the 16-QAM signals are simultaneously injected into the deep PRC in parallel, based on the wavelength multiplexing of Fabry-Perot lasers. It is demonstrated that the deep PRC exhibits strong capability for the nonlinearity compensation of coherent signals. The Q factor is improved by more than 1 dB for 16-QAM signals with launch powers above 10 dBm, associated with a bit rate of 240 Gbps and a transmission distance of 50 km.