Coherent frequency microcombs,generated in nonlinear high-Q microresonators and driven by a single continuouswave laser,have enabled several scientific breakthroughs in the past decade,thanks to their high intrinsic p...Coherent frequency microcombs,generated in nonlinear high-Q microresonators and driven by a single continuouswave laser,have enabled several scientific breakthroughs in the past decade,thanks to their high intrinsic phase coherence and individual comb line powers.Here,we report terabit-per-second-scale coherent data communications over a free-space atmospheric link,using a platicon frequency microcomb,employing wavelength-and polarizationdivision multiplexing for next-generation optical wireless networks.Spanning more than 55 optical carriers with 115 GHz channel spacing,we report the first free-space coherent communication link using a frequency microcomb,achieving up to 8.21 Tbit/s aggregate data transmission at a 20 Gbaud symbol rate per carrier over 160 m,even under log-normal turbulent conditions.Utilizing 16-state quadrature amplitude modulation,we demonstrate retrieved constellation maps across the broad microcomb spectrum,achieving bit-error rates below both hardand soft-decision thresholds for forward-error correction.Next,we examine a wavelength-division multiplexing free-space passive optical network as a baseline for free-space fronthaul,achieving an aggregate data rate of up to 5.21 Tbit/s and a field-tested spectral efficiency of 1.29 bit/s/Hz in the microcomb-based atmospheric link.We also quantify experimental power penalties of≈3.8 dB at the error-correction threshold,relative to the theoretical additive white Gaussian noise limit.Furthermore,we introduce the first-ever demonstration of master–slave free-space carrier phase retrieval with frequency microcombs,and the compensation for turbulence-induced intensity scintillation and pointing error fluctuations,to improve end-to-end symbol error rates.This work provides a foundational platform for broadband vertical heterogeneous connectivity,terrestrial backbone links,and groundsatellite communication.展开更多
基金financial support from the Office of Naval Research(N00014-16-1-2094)the National Science Foundation(1824568,1810506,1741707,and 1919355).
文摘Coherent frequency microcombs,generated in nonlinear high-Q microresonators and driven by a single continuouswave laser,have enabled several scientific breakthroughs in the past decade,thanks to their high intrinsic phase coherence and individual comb line powers.Here,we report terabit-per-second-scale coherent data communications over a free-space atmospheric link,using a platicon frequency microcomb,employing wavelength-and polarizationdivision multiplexing for next-generation optical wireless networks.Spanning more than 55 optical carriers with 115 GHz channel spacing,we report the first free-space coherent communication link using a frequency microcomb,achieving up to 8.21 Tbit/s aggregate data transmission at a 20 Gbaud symbol rate per carrier over 160 m,even under log-normal turbulent conditions.Utilizing 16-state quadrature amplitude modulation,we demonstrate retrieved constellation maps across the broad microcomb spectrum,achieving bit-error rates below both hardand soft-decision thresholds for forward-error correction.Next,we examine a wavelength-division multiplexing free-space passive optical network as a baseline for free-space fronthaul,achieving an aggregate data rate of up to 5.21 Tbit/s and a field-tested spectral efficiency of 1.29 bit/s/Hz in the microcomb-based atmospheric link.We also quantify experimental power penalties of≈3.8 dB at the error-correction threshold,relative to the theoretical additive white Gaussian noise limit.Furthermore,we introduce the first-ever demonstration of master–slave free-space carrier phase retrieval with frequency microcombs,and the compensation for turbulence-induced intensity scintillation and pointing error fluctuations,to improve end-to-end symbol error rates.This work provides a foundational platform for broadband vertical heterogeneous connectivity,terrestrial backbone links,and groundsatellite communication.
