title: Transmission of 8 × 480-Gb/s super-Nyquist-filtering 9-QAM-like signal at 100 GHz-grid over 5000-km SMF-28 and twenty-five 100 GHz-grid ROADMs.
abstract: We experimentally demonstrate a highly filtering-tolerant multi-modulus equalization (MMEQ) process for very aggressively spectrum-shaped 9-ary quadrature-amplitude-modulation (9-QAM)-like polarization division multiplexing quadrature phase shift keying (PDM-QPSK) signal to achieve 400-Gb/s wavelength-division-multiplexing (WDM) channels on the 100-GHz grid for ultra-long-haul reach and high tolerance of the filter narrowing effect caused by reconfigurable optical add-drop multiplexers (ROADMs). We successfully transmitted 8 channels 480-Gb/s super-Nyquist (channel occupancy much less than signal baud rate) WDM signals at 100-GHz grid over 25 × 200 km conventional single-mode fiber-28 (SMF-28) with post Raman amplification and 25 ROADMs at a net spectral efficiency (SE) of 4b/s/Hz, after excluding the 20% soft-decision forward-error-correction (FEC) overhead. The system performance is significantly enhanced by the MMEQ based on 9-QAM-like constellations compared to the conventional 4 point QPSK constellation. A record transmission distance over conventional SMF-28 with a large number of ROADMs is firstly reported on the 400-Gb/s channels at 100-GHz grid.
authors.affiliation: 1ZTE Corp, Beijing 100191, China. yu.jianjun@zte.com.cn
authors.forename: Jianjun
authors.initials: J
authors.lastname: Yu
authors.forename: Junwen
authors.initials: J
authors.lastname: Zhang
authors.forename: Ze
authors.initials: Z
authors.lastname: Dong
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Jia
authors.forename: Hung-Chang
authors.initials: HC
authors.lastname: Chien
authors.forename: Yi
authors.initials: Y
authors.lastname: Cai
authors.forename: Xin
authors.initials: X
authors.lastname: Xiao
authors.forename: Xinying
authors.initials: X
authors.lastname: Li