title: Photonic RF vector signal generation with enhanced spectral efficiency using precoded double single-sideband modulation.
abstract: In this study, a novel photonic vector signal at frequency (RF) bands generation scheme based on the beating of double single sidebands (SSBs) is proposed and experimentally demonstrated. The double SSBs carry separate constant- or multi-amplitude quadrature-amplitude-modulation vector signals are generated from a single I/Q modulator. By adopting phase and amplitude precoding, different constellations can be generated, such as 3-ary phase-shift keying (PSK), 4-PSK, 7-PSK, 8-PSK, and so on. In this work, 10-Gbaud 7-PSK vector signal generation at 20 GHz enabled by two precoded 4-PSK SSB signals via a single I/Q modulator is theoretically and experimentally investigated. Compared to a single-drive Mach-Zehnder modulator or conventional I/Q modulator-based photonic vector signal generation scheme, the spectrum efficiency can be doubled. Differential coding is also implemented at the transmitter side for accurate demodulation of 7-PSK into two 4-PSK signals. The bit-error ratio for 10-Gbaud 7-PSK vector signals can be under hard-decision forward-error-correction threshold of 3.8×10-3after 10 km standard single-mode fiber transmission.
authors.forename: Yuanquan
authors.initials: Y
authors.lastname: Wang
authors.forename: Hung-Chang
authors.initials: HC
authors.lastname: Chien
authors.forename: HaiChao
authors.initials: H
authors.lastname: Guo
authors.forename: Jianjun
authors.initials: J
authors.lastname: Yu
authors.forename: Gee-Kung
authors.initials: GK
authors.lastname: Chang
authors.forename: Nan
authors.initials: N
authors.lastname: Chi