In this paper, to achieve higher robustness against atmospheric turbulence for high-capacity free-space optical (FSO) communications, an adaptive multi-modal FSO transceiver has been designed and experimentally demonstrated. We show that based on the dynamically estimated channel state information, modulation formats and power for different transmit modes can be adaptively allocated at the transmitter side. Meanwhile, at the receiver side, we show that the most suitable multi-input/multi-output decoder can be selected and employed to meet the requirement of forward error correction at the minimal expense of power consumption. By employing time-division multiplexed transmitter and receiver emulation and a spatial light modulator for turbulence emulation, an aggregate data rate of 590 Gbit/s/wavelength has been achieved when suffering from strong atmospheric turbulence, verifying the feasibility of the proposed adaptive transceiver over a turbulent FSO link. Moreover, to demonstrate practical applicability, all key devices such as transponder, multiplexer, and demultiplexer are commercially available in this work.
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Funding: Research supported by EPSRC under grant number EP/T009047/1, EP/T009012/1, EP/S003436/1, EP/S016171/1, and the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 713694.
- Atmospheric turbulence
- Channel estimation
- MIMO communication
- Optical receivers
- Optical transmitters
- free-space optics (FSO)
- mode-division multiplexing (MDM)
- multiple-input multiple-output (MIMO)
- optical wireless communication