A single-end adaptive-optics(AO)module is experimentally demonstrated to mitigate the emulated atmospheric turbulence efects in a bi-directional quantum communication link,which employs orbital angular momentum(OAM)fo...A single-end adaptive-optics(AO)module is experimentally demonstrated to mitigate the emulated atmospheric turbulence efects in a bi-directional quantum communication link,which employs orbital angular momentum(OAM)for data encoding.A classical Gaussian beam is used as a probe to detect the turbulence-induced wavefront distortion in the forward direction of the link.Based on the detected wavefront distortion,an AO system located on one end of the link is used to simultaneously compensate for the forward and backward channels.Specifcally,with emulated turbulence and when the probe is turned on,the mode purity of photons carrying OAMℓ=1 is improved by∼21%with AO mitigation.We also measured the performance when encoding data using OAM{ℓ=−1,+2}and{ℓ=−2,+1}in the forward and backward channels,respectively,at 10 Mbit/s per channel with one photon per pulse on average.For this case,we found that the AO system could reduce the turbulence efects increased quantum-symbolerror-rate(QSER)by∼76%and∼74%,for both channels in the uni-directional and bi-directional cases,respectively.Similar QSER improvement is observed for the opposite direction channels in the bi-directional case.展开更多
Stimulated Brillouin scattering(SBS)in optical fibers has long been used in frequency-selective optical signal processing,including in the realization of microwave-photonic(MWP)filters.In this work,we report a signifi...Stimulated Brillouin scattering(SBS)in optical fibers has long been used in frequency-selective optical signal processing,including in the realization of microwave-photonic(MWP)filters.In this work,we report a significant enhancement in the selectivity of SBS-based MWP filters.Filters having a single passband of 250 MHz–1 GHz bandwidth are demonstrated,with selectivity of up to 44 dB.The selectivity of the filters is better than that of the corresponding previous arrangements by about 15 dB.The shape factor of the filters,defined as the ratio between their−20 dB bandwidth and their−3 dB bandwidth,is between 1.35 and 1.5.The central transmission frequency,bandwidth,and spectral shape of the passband are all independently adjusted.Performance enhancement is based on two advances,compared with previous demonstrations of tunable SBS-basedMWPfilters:(a)the polarization attributes of SBS in standard,weakly birefringent fibers are used to discriminate between in-band and out-of-band components and(b)a sharp and uniform power spectral density of the SBS pump waves is synthesized through external modulation of an optical carrier by broadband,frequency-swept waveforms.The signal-to-noise ratio of filtered radio-frequency waveforms and the linear dynamic range of the filters are estimated analytically and quantified experimentally.Lastly,a figure of merit for the performance of the filters is proposed and discussed.The filters are applicable to radio-over-fiber transmission systems.展开更多
Orbital angular momentum(OAM) has gained interest due to its potential to increase capacity in optical communication systems as well as an additional domain for reconfigurable networks. This is due to the following:(i...Orbital angular momentum(OAM) has gained interest due to its potential to increase capacity in optical communication systems as well as an additional domain for reconfigurable networks. This is due to the following:(i) coaxially propagated OAM beams with different charges are mutually orthogonal,(ii) OAM beams can be efficiently multiplexed and demultiplexed, and(iii) OAM charges can be efficiently manipulated. Therefore, multiple data-carrying OAM beams could have the potential capability for reconfigurable optical switching and routing. In this paper, we discuss work involving reconfigurable OAM-based optical add/drop multiplexing, space switching,polarization switching, channel hopping, and multicasting.展开更多
基金This work is supported by the Ofce of Naval Research(ONR)[N00014-15-1-2635]the Vannevar Bush Faculty Fellowship program sponsored by the Basic Research Ofce of the Assistant Secretary of Defense for Research and Engineering and funded by ONR[N00014-16-1-2813]the National Science Foundation(NSF)[ECCS-1509965].
文摘A single-end adaptive-optics(AO)module is experimentally demonstrated to mitigate the emulated atmospheric turbulence efects in a bi-directional quantum communication link,which employs orbital angular momentum(OAM)for data encoding.A classical Gaussian beam is used as a probe to detect the turbulence-induced wavefront distortion in the forward direction of the link.Based on the detected wavefront distortion,an AO system located on one end of the link is used to simultaneously compensate for the forward and backward channels.Specifcally,with emulated turbulence and when the probe is turned on,the mode purity of photons carrying OAMℓ=1 is improved by∼21%with AO mitigation.We also measured the performance when encoding data using OAM{ℓ=−1,+2}and{ℓ=−2,+1}in the forward and backward channels,respectively,at 10 Mbit/s per channel with one photon per pulse on average.For this case,we found that the AO system could reduce the turbulence efects increased quantum-symbolerror-rate(QSER)by∼76%and∼74%,for both channels in the uni-directional and bi-directional cases,respectively.Similar QSER improvement is observed for the opposite direction channels in the bi-directional case.
基金by the Israel Science Foundation(ISF,Grant No.1380/12).K.Zhong acknowledges the China Scholarship Council(CSC)for support of his research stay at Bar-Ilan Universityby the National Natural Science Foundation of China(Grant Nos.60937003 and 61177085).
文摘Stimulated Brillouin scattering(SBS)in optical fibers has long been used in frequency-selective optical signal processing,including in the realization of microwave-photonic(MWP)filters.In this work,we report a significant enhancement in the selectivity of SBS-based MWP filters.Filters having a single passband of 250 MHz–1 GHz bandwidth are demonstrated,with selectivity of up to 44 dB.The selectivity of the filters is better than that of the corresponding previous arrangements by about 15 dB.The shape factor of the filters,defined as the ratio between their−20 dB bandwidth and their−3 dB bandwidth,is between 1.35 and 1.5.The central transmission frequency,bandwidth,and spectral shape of the passband are all independently adjusted.Performance enhancement is based on two advances,compared with previous demonstrations of tunable SBS-basedMWPfilters:(a)the polarization attributes of SBS in standard,weakly birefringent fibers are used to discriminate between in-band and out-of-band components and(b)a sharp and uniform power spectral density of the SBS pump waves is synthesized through external modulation of an optical carrier by broadband,frequency-swept waveforms.The signal-to-noise ratio of filtered radio-frequency waveforms and the linear dynamic range of the filters are estimated analytically and quantified experimentally.Lastly,a figure of merit for the performance of the filters is proposed and discussed.The filters are applicable to radio-over-fiber transmission systems.
基金Air Force Office of Scientific Research(AFOSR)FA9550-15-C-0024Defense Advanced Research Projects Agency(DARPA)+2 种基金National Science Foundation(NSF)ECCS-1509965)Nx Gen PartnersOffice of Naval Research(ONR)416678-G
文摘Orbital angular momentum(OAM) has gained interest due to its potential to increase capacity in optical communication systems as well as an additional domain for reconfigurable networks. This is due to the following:(i) coaxially propagated OAM beams with different charges are mutually orthogonal,(ii) OAM beams can be efficiently multiplexed and demultiplexed, and(iii) OAM charges can be efficiently manipulated. Therefore, multiple data-carrying OAM beams could have the potential capability for reconfigurable optical switching and routing. In this paper, we discuss work involving reconfigurable OAM-based optical add/drop multiplexing, space switching,polarization switching, channel hopping, and multicasting.
