Digital pilot aided carrier frequency offset estimation for coherent optical transmission systems Zhao, Donghe ; Xi, Lixia ; Tang, Xianfeng ; Zhang, Wenbo ; Qiao, Yaojun ; Zhang, Xiaoguang Abstract Publication: Optics Express Pub Date: September 2015 DOI: 10.1364/OE.23.024822 Bibcode: 2015OExpr..2324822Z