Abstract
We experimentally demonstrate 10-channel mode-division
multiplexed free-space optical transmission with five spatial modes, each carrying 19.6925-Gbaud dual-polarization
quadrature phase shift keying signals. Strong inter-mode
cross talk is observed in our commercially available photonic
lantern based system when using a complete orthogonal
mode set as independent channels. A successive interference
cancellation based multiple-input multiple-output digital
signal processing (DSP) algorithm is first applied to mitigate the inter-mode cross talk in mode-division multiplexed
systems. The DSP also supports unequal transmit and
receive channel numbers to further improve the cross talk
resiliency. Compared to the conventional minimum mean
square error DSP, the required optical signal-to-noise ratio
of the successive interference cancellation DSP is decreased
by approximately 5 dB at the hard-decision forward error
correction limit. As a result, this system demonstrates a
record-high independent channel number of 10 and spectral efficiency of 13.7 b/s/Hz in mode-division multiplexed
free-space optical systems.
multiplexed free-space optical transmission with five spatial modes, each carrying 19.6925-Gbaud dual-polarization
quadrature phase shift keying signals. Strong inter-mode
cross talk is observed in our commercially available photonic
lantern based system when using a complete orthogonal
mode set as independent channels. A successive interference
cancellation based multiple-input multiple-output digital
signal processing (DSP) algorithm is first applied to mitigate the inter-mode cross talk in mode-division multiplexed
systems. The DSP also supports unequal transmit and
receive channel numbers to further improve the cross talk
resiliency. Compared to the conventional minimum mean
square error DSP, the required optical signal-to-noise ratio
of the successive interference cancellation DSP is decreased
by approximately 5 dB at the hard-decision forward error
correction limit. As a result, this system demonstrates a
record-high independent channel number of 10 and spectral efficiency of 13.7 b/s/Hz in mode-division multiplexed
free-space optical systems.
| Original language | English |
|---|---|
| Pages (from-to) | 2742-2745 |
| Number of pages | 4 |
| Journal | Optics Letters |
| Volume | 47 |
| Issue number | 11 |
| Early online date | 20 May 2022 |
| DOIs | |
| Publication status | Published - 1 Jun 2022 |
Bibliographical note
Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Funding: H2020 Marie Skłodowska-Curie Actions (713694); Engineering and Physical Sciences Research Council (EP/S003436/1, EP/S016171/1,
EP/T009047/1).