Thomas Lee Elifritz

http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2012.138.html

Terabit free-space data transmission employing orbital angular momentum multiplexing, Jian Wang, Jeng-Yuan Yang, Irfan M. Fazal, Nisar Ahmed, Yan Yan, Hao Huang, Yongxiong Ren, Yang Yue, Samuel Dolinar, Moshe Tur and Alan E. Willner, Nature Photonics, 24 June 2012

We demonstrate that four light beams with different values of orbital angular momentum and encoded with 42.8 × 4 Gbit s⁻¹ quadrature amplitude modulation (16-QAM) signals can be multiplexed and demultiplexed, allowing a 1.37 Tbit s⁻¹ aggregated rate and 25.6 bit s⁻¹ Hz⁻¹ spectral efficiency when combined with polarization multiplexing. Moreover, we show scalability in the spatial domain using two groups of concentric rings of eight polarization-multiplexed 20 × 4 Gbit s⁻¹ 16-QAM-carrying orbital angular momentum beams, achieving a capacity of 2.56 Tbit s⁻¹ and spectral efficiency of 95.7 bit s⁻¹ Hz⁻¹. We also report data exchange between orbital angular momentum beams encoded with 100 Gbit s⁻¹ differential quadrature phase-shift keying signals.

Wow, that was quick.

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