Chinese Optics Letters, Vol. 17, Issue 10, 100004 (2019)
50 Gb/s PAM4 underwater wireless optical communication systems across the water–air–water interface [Invited]
Chung-Yi Li1, Hai-Han Lu2,*, Yong-Cheng Huang2, Qi-Ping Huang2, Jing-Yan Xie2, and Song-En Tsai2
- 1Department of Communication Engineering, Taipei University, New Taipei City 237, China
- 2Institute of Electro-Optical Engineering, Taipei University of Technology, Taipei 106, China
A 50 Gb/s four-level pulse amplitude modulation (PAM4) underwater wireless optical communication (UWOC) system across the water–air–water interface is demonstrated in practice. In practical scenarios, laser beam misalignment due to oceanic turbulence degrades performance in UWOC systems. With the adoption of a reflective spatial light modulator (SLM) with an electrical controller, not only can the laser be arbitrarily adjusted to attain a water–air–water scenario, but oceanic engineering problems can also be resolved to establish a reliable UWOC link. Brilliant bit error rate performance and clear PAM4 eye diagrams are attained by adopting a Keplerian beam expander and a reflective SLM with an electrical controller. This proposed PAM4 UWOC system presents a feasible state that outperforms existing UWOC systems due to its feature providing a high-speed water–air–water link.