A high-speed underwater optical communications link that operates at a data rate
of 4.8 Gbits s−1 over a distance of 5.4 m has been demonstrated by scientists
in Saudi Arabia and Taiwan. The link is the result of work by Hassan Oubei
and co-workers from King Abdullah University of Science and Technology (KAUST),
National Taiwan University and National Chiao Tung University. It makes use of
a 15 mW blue laser diode with a wavelength of 450 nm to transmit light pulses
in the blue-green low-absorption window of seawater, which are then detected
by a silicon avalanche photodiode-based receiver. A 16-QAM-OFDM modulation
and multiplexing format is used to optimize the links signal-to-noise ratio
(15.63 dB) and bit error rate (2.6 × 10−3). Such high-speed underwater
communication links are expected to be useful for providing data connections
to sensor networks and remotely operated vehicles.

Nature Photonics 9, 707 (2015) doi:10.1038/nphoton.2015.218

Published online 29 October 2015

http://www.nature.com/nphoton/journal/v9/n11/full/nphoton.
2015.218.html?WT.ec_id=NPHOTON-201511&spMailingID=49887820&
spUserID=MTMyMTU5MzI1NDg5S0&spJobID=784049983&spReportId=
Nzg0MDQ5OTgzS0

Optics Express 23, 23302–23309 (2015), doi: 10.1364/OE.23.023302

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-23-18-23302