title: 2048 QAM (66 Gbit/s) single-carrier coherent optical transmission over 150 km with a potential SE of 15.3 bit/s/Hz.
abstract: We describe a 2048 QAM single-carrier coherent optical transmission over 150 km in detail. The OSNR at the transmitter was increased by 5 dB and the phase noise at the receiver was reduced from 0.35 to 0.17 degrees compared with a previous 1024 QAM transmission. Furthermore, we employed an A/D converter with a higher ENOB (7 bit) to guarantee the SNR of the digital QAM data, and introduced a polarization-demultiplexing algorithm to fast track the polarization state transition. As a result, a 66 Gbit/s polarization-multiplexed 2048 QAM signal was successfully transmitted within an optical bandwidth of 3.6 GHz including a pilot tone, and a potential SE of 15.3 bit/s/Hz under a 20% FEC overhead was achieved.
authors.forename: Shohei
authors.initials: S
authors.lastname: Beppu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kasai
authors.forename: Masato
authors.initials: M
authors.lastname: Yoshida
authors.forename: Masataka
authors.initials: M
authors.lastname: Nakazawa