supported by the National Natural Science Foundation of China(NSFC)(No.61971378);Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22030208);Zhoushan-Zhejiang University Joint Research Project(No.2019C81081)。
In this paper,an optical pulse amplitude modulation with 4 levels(PAM-4)using a fiber combiner is proposed to enhance the data rate of a field-programmable gate-array-based long-distance real-time underwater wireless ...