Real-time 400 Gbps/carrier WDM transmission over 2,000 km of field-installed G.654.E fiber

We combine erbium-doped fiber amplifier (EDFA) and backward distributed Raman amplifier (DRA) to achieve the real-time wavelength division multiplexing (WDM) transmission of 400 Gbps/carrier polarization division multiplexing (PDM) 16 quadrature amplitude modulation (QAM) signals over 2,000 km of terrestrial field-deployed cut-off shifted fiber (CSF) compliant with ITU-T G.654.E. This paper compares the transmission performance of 400 Gbps/carrier signals achieved in CSF and standard single-mode fiber (SMF). This transmission distance, 2,019 km, is, to the best of our knowledge, the longest in 400 Gbps/carrier WDM transmission field experiments using digital signal processing (DSP) application specific integrated circuit (ASIC) integrated real-time optical transponders with the technologies to compensate device imperfections; the backward DRA used is fully compliant with laser power safety requirements.