Low-Resolution Digital Pre-Compensation Enabled by Digital Resolution Enhancer

Digital pre-compensation (DPC) is an indispensable block of state-of-the-art optical transceivers, and a key enabler for high-order modulation formats (HOMFs) transmission. A crucial component, which enables the transmission of the precompensated HOMFs, is the digital-to-analog-converter (DAC). However, as data and symbol rates grow, the implementation of such devices becomes highly challenging in terms of performance, power consumption, and costs. In this paper, a digital-resolution-enhancer (DRE) algorithm is discussed, conjoined with high-end DPC methods. Simulation results demonstrate that the DRE reduces the effect of DAC quantization noise power by more than 8 dB for the considered cases of 400G with 64QAM. The proposed scheme is experimentally verified by transmitting a 4-bit DP-64QAM 400 Gbit/s signal in a WDM scenario over 95 km of single mode fiber.