title: Experimental demonstration of iterative post-equalization algorithm for 37.5-Gbaud PM-16QAM quad-carrier Terabit superchannel.
abstract: We experimentally demonstrate a quad-carrier 1-Tb/s solution with 37.5-GBaud PM-16QAM signal over 37.5-GHz optical grid at 6.7 b/s/Hz net spectral efficiency. Digital Nyquist pulse shaping at the transmitter and post-equalization at the receiver are employed to mitigate the impairments of joint inter-symbol-interference (ISI) and inter-channel-interference (ICI) symbol degradation. The post-equalization algorithms consist of one sample/symbol based decision-directed least mean square (DD-LMS) adaptive filter, digital post filter and maximum likelihood sequence estimation (MLSE), and a positive iterative process among them. By combining these algorithms, the improvement as much as 4-dB OSNR (0.1nm) at SD-FEC limit (Q(2) = 6.25 corresponding to BER = 2.0e-2) is obtained when compared to no such post-equalization process, and transmission over 820-km EDFA-only standard single-mode fiber (SSMF) link is achieved for two 1.2-Tb/s signals with the averaged Q(2) factor larger than 6.5 dB for all sub-channels. Additionally, 50-GBaud 16QAM operating at 1.28 samples/symbol in a DAC is also investigated and successful transmission over 410-km SSMF link is achieved at 62.5-GHz optical grid.
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: Jianjun
authors.initials: J
authors.lastname: Yu
authors.forename: Chengliang
authors.initials: C
authors.lastname: Zhang
authors.forename: Junjie
authors.initials: J
authors.lastname: Li
authors.forename: Yiran
authors.initials: Y
authors.lastname: Ma
authors.forename: Dongdong
authors.initials: D
authors.lastname: Shang
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Sheping
authors.initials: S
authors.lastname: Shi
authors.forename: Huitao
authors.initials: H
authors.lastname: Wang