High Spectral Efficiency Real-Time 500-Gb/s/carrier Long-Haul Transmission Over Field-Installed Fibers

Abstract

We demonstrated high spectral efficiency real-time 500-Gb/s/carrier transmission over a 1200 km length with terrestrial field-installed cut-off shifted fiber (CSF) of ITU-T G.654.E compliant. For that demonstration, we used our real-time transponder and a combination of three amplification schemes (erbium-doped fiber amplifier (EDFA), and forward and backward distributed Raman amplifiers (DRAs)) that met safety requirements for lasers as defined by safety standard IEC 60825-2. By using forward DRA, optical signal-to-noise ratio (OSNR) improved by more than 1.3 dB. 66-GBaud polarization division multiplexing (PDM) 32 quadrature amplitude modulation (QAM) signals were generated by a real-time transponder using a 16-nm digital signal processing application-specific integrated circuit (DSP-ASIC) with device imperfection compensation technologies. We compared the 500-Gb/s/carrier transmission characteristics in a wavelength-division multiplexing (WDM) condition yielded by CSF, standard single-mode fiber (SMF), and dispersion-shifted fiber (DSF) installed in the field. The results show that the best transmission characteristics are attained by CSF transmission with forward DRA. The 1234-km transmission achieved with high spectral efficiency of 5.71 b/s/Hz, is, as far as we know, the longest yet achieved in 500-Gb/s/carrier transmission field experiments.