Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications
Abstract
To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we show up to a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam; we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the 40-Gbit/s link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the 4-Gbit/s link, a green laser diode is directly modulated. Finally, we show that inter-channel crosstalk induced by thermal gradients can be mitigated using multi-channel equalisation processing.
Additional Information
© 2016 Macmillan Publishers Limited. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ Received: 15 June 2016. Accepted: 24 August 2016. Published online: 12 September 2016. We acknowledge James M. Krause, Michael J. Luddy, and Jack H. Winters for valuable help and fruitful discussions. S.M.K. is supported by 'Light-Material Interactions in Energy Conversion' Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. E.A. and A.A. are supported by Samsung Electronics. Device nanofabrication was performed at the Kavli Nanoscience Institute at California Institute of Technology. This work is supported by Vannever Bush Faculty Fellowship from ASD (R&E) and ONR, the National Science Foundation, and NxGen Partners. Yongxiong Ren & Long Li: These authors contributed equally to this work. Author Contributions: Y.R., L.L. and A.E.W. developed the concept and designed the experiments. Y.R., L.L., Z.Z., G.X., Z.W., N.A., Y.Y., C.L. and A.J.W carried out the measurements and analysed the data. L.L., Y.C. and Y.R. designed and implemented the multiple-input-multiple-output equalisation algorithm. S.M.K., E.A., A.A. and A.F. designed, fabricated, and characterized the metasurface OAM generator phase masks. S.A., M.T., A.F. and A.E.W. provided technical support. The project was conceived and supervised by A.E.W. The authors declare no competing financial interests.Attached Files
Published - srep33306.pdf
Submitted - 1604.06865.pdf
Supplemental Material - srep33306-s1.pdf
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Additional details
- PMCID
- PMC5018855
- Eprint ID
- 70421
- Resolver ID
- CaltechAUTHORS:20160919-101452405
- Department of Energy (DOE)
- Samsung Electronics
- Vannever Bush Faculty Fellowship
- Office of Naval Research (ONR)
- NSF
- NxGen Partners
- Created
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2016-09-28Created from EPrint's datestamp field
- Updated
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2022-04-19Created from EPrint's last_modified field
- Caltech groups
- Kavli Nanoscience Institute