Data availability
All the data in this study are openly available in the NTU research data repository DR-NTU at https://doi.org/10.21979/N9/UKLX3D.
References
Alsharif, M. H. & Nordin, R. Evolution towards fifth generation (5G) wireless networks: current trends and challenges in the deployment of millimetre wave, massive MIMO, and small cells. Telecommun. Syst. 64, 617–637 (2017).
Dang, S., Amin, O., Shihada, B. & Alouini, M.-S. What should 6G be? Nat. Electron. 3, 20–29 (2020).
Akyildiz, I. F., Kak, A. & Nie, S. 6G and beyond: the future of wireless communications systems. IEEE Access 8, 133995–134030 (2020).
Rappaport, T. S. et al. Wireless communications and applications above 100 GHz: opportunities and challenges for 6G and beyond. IEEE Access 7, 78729–78757 (2019).
Nagatsuma, T., Ducournau, G. & Renaud, C. C. Advances in terahertz communications accelerated by photonics. Nat. Photon. 10, 371–379 (2016).
Article ADS CAS Google Scholar
Akyildiz, I. F., Jornet, J. M. & Han, C. Terahertz band: next frontier for wireless communications. Phys. Commun. 12, 16–32 (2014).
Koenig, S. et al. Wireless sub-THz communication system with high data rate. Nat. Photon. 7, 977–981 (2013).
Article ADS CAS Google Scholar
Fu, X., Yang, F., Liu, C., Wu, X. & Cui, T. J. Terahertz beam steering technologies: from phased arrays to field-programmable metasurfaces. Adv. Opt. Mater. 8, 1900628 (2020).
Monnai, Y., Lu, X. & Sengupta, K. Terahertz beam steering: from fundamentals to applications. J. Infrared Millim. Terahertz Waves 44, 169–211 (2023).
Tan, Y. J. et al. Self-adaptive deep reinforcement learning for THz beamforming with silicon metasurfaces in 6G communications. Opt. Express 30, 27763–27779 (2022).
Sengupta, K. & Hajimiri, A. A 0.28 THz power-generation and beam-steering array in CMOS based on distributed active radiators. IEEE J. Solid-State Circuits 47, 3013–3031 (2012).
Tousi, Y. & Afshari, E. A high-power and scalable 2-D phased array for terahertz CMOS integrated systems. IEEE J. Solid-State Circuits 50, 597–609 (2015).
Che, M. et al. Optoelectronic THz-wave beam steering by arrayed photomixers with integrated antennas. IEEE Photon. Technol. Lett. 32, 979–982 (2020).
Article ADS CAS Google Scholar
Sengupta, K., Nagatsuma, T. & Mittleman, D. M. Terahertz integrated electronic and hybrid electronic–photonic systems. Nat. Electron. 1, 622–635 (2018).
Zeng, Y. et al. Electrically pumped topological laser with valley edge modes. Nature 578, 246–250 (2020).
Shalaev, M. I., Walasik, W., Tsukernik, A., Xu, Y. & Litchinitser, N. M. Robust topologically protected transport in photonic crystals at telecommunication wavelengths. Nat. Nanotechnol. 14, 31–34 (2019).
Gao, F. et al. Topologically protected refraction of robust kink states in valley photonic crystals. Nat. Phys. 14, 140–144 (2018).
Dong, J.-W., Chen, X.-D., Zhu, H., Wang, Y. & Zhang, X. Valley photonic crystals for control of spin and topology. Nat. Mater. 16, 298–302 (2017).
Ma, T. & Shvets, G. All-Si valley-Hall photonic topological insulator. New J. Phys. 18, 025012 (2016).
Yang, Y. et al. Terahertz topological photonics for on-chip communication. Nat. Photon. 14, 446–451 (2020).
Article ADS CAS Google Scholar
Kumar, A. et al. Phototunable chip-scale topological photonics: 160 Gbps waveguide and demultiplexer for THz 6G communication. Nat. Commun. 13, 5404 (2022).
Jia, R. et al. Valley-conserved topological integrated antenna for 100-Gbps THz 6G wireless. Sci. Adv. 9, eadi8500 (2023).
Hatsugai, Y. Edge states in the integer quantum Hall effect and the Riemann surface of the Bloch function. Phys. Rev. B 48, 11851–11862 (1993).
Article ADS CAS Google Scholar
Balanis, C. A. Modern Antenna Handbook (Wiley, 2011).
Sen, P., Siles, J. V., Thawdar, N. & Jornet, J. M. Multi-kilometre and multi-gigabit-per-second sub-terahertz communications for wireless backhaul applications. Nat. Electron. 6, 164–175 (2023).
Acknowledgements
We acknowledge the support from the National Research Foundation (NRF) Singapore, grant no. NRF-CRP23-2019-0005 (TERACOMM). G.D. and P.S. acknowledge the characterization testbeds supported by the France 2030 programmes, PEPR (Programmes et Equipements Prioritaires pour la Recherche) and CPER Wavetech. The PEPR is operated by the Agence Nationale de la Recherche (ANR), under the grants ANR-22-PEEL-0006 (FUNTERA, PEPR ‘Electronics’) and ANR-22-PEFT-0006 (NF-SYSTERA, PEPR 5 G and beyond—Future Networks). The Contrat de Plan Etat-Region (CPER) WaveTech is supported by the Ministry of Higher Education and Research, the Hauts-de-France Regional Council, the Lille European Metropolis (MEL), the Institute of Physics of the French National Centre for Scientific Research (CNRS) and the European Regional Development Fund (ERDF).
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Authors and Affiliations
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
Wenhao Wang,Yi Ji Tan,Thomas CaiWei Tan,Abhishek Kumar&Ranjan Singh
Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, Singapore, Singapore
Wenhao Wang,Yi Ji Tan,Thomas CaiWei Tan,Abhishek Kumar&Ranjan Singh
Institute of Microelectronics, Agency for Science, Technology and Research, Singapore, Singapore
Prakash Pitchappa
Université de Lille, CNRS, UMR 8523 - PhLAM, Laboratoire de Physique des Lasers, Atomes et Molécules, Lille, France
Pascal Szriftgiser
Université de Lille, CNRS, UMR 8520 - IEMN, Institut d’Electronique, Microélectronique et Nanotechnologie, Lille, France
Guillaume Ducournau
Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, USA
Ranjan Singh
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Contributions
W.W. and R.S. conceived the idea; W.W., Y.J.T., A.K. and R.S. designed the experiments; W.W. performed the simulation; Y.J.T. performed the NN-assisted inverse design of the topological beamformers; P.P. fabricated a portion of the intrinsic AB-type topological beamformer samples; T.C.T. led the overall sample fabrication; W.W. performed the on-chip transmission and two-dimensional radiation pattern measurements with the help of T.C.T.; W.W. and R.S. designed the phototunable beamforming experiment; W.W. performed the active tuning measurements with the help of T.C.T.; G.D. performed the vector network analyser transmission, antenna gain and 3D radiation pattern measurements; P.S. and G.D. performed THz wireless communication experiments; W.W., Y.J.T., A.K., G.D. and R.S. analysed all the data; W.W. and R.S. wrote the paper with inputs from all co-authors; and R.S. led the overall project.
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Correspondence to Ranjan Singh.
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Extended data figures and tables
Extended Data Fig. 1 Topological power splitters.
Optical images of four-channel (4-CH) a AB-type and b BA-type topological power splitters. Type A (B) VPC unit cell is highlighted with a purple (orange) color. The AB-type and BA-type zigzag interfaces are marked with red and blue dotted lines, respectively. The 4-CH AB-type (BA-type) power splitter is composed of an AB-type (BA-type) zigzag interface on the left channel CH 1 and three BA-type (AB-type) zigzag interfaces on the right channels CHs 2-4.
Extended Data Fig. 2 Intrinsic broadband topological waveguide phased arrays.
Simulated a (c) transmission and b (d) phase of the 16 radiating channels of AB- (BA-) type four-stage topological beamformer. The 16 channels of AB- (BA-) type beamformer have similar transmission while showing intrinsic π (0) phase difference between adjacent channels over the entire broad bandwidth of 26.5 GHz (18.9 GHz). e Simulated and measured transmission of BA-type topological beamformers having different numbers of tapers by summing the transmission of all the channels. The shaded gray area of the measured transmission spectrum indicates the standard error.
Extended Data Fig. 3 Optical images of AB-type topological beamformers.
The optical images show the evolution of the AB-type topological beamformers from the zero-stage having 20 = 1 output taper to four-stage having 24 = 16 output tapers.
Extended Data Fig. 4 Evolution of the far-field radiation pattern of intrinsic AB-type topological beamformer with the stage number.
a,b,c Measured and simulated azimuthal radiation patterns of the intrinsic AB-type two-, three-, and four-stage topological beamformers at the horizontal plane (polar angle ϕ = 0°) at 0.325 THz. d,e,f Measured 3D radiation patterns at 0.325 THz for the space θ > 0°. g,h,i Measured broadband radiation patterns. As the number of taper (radiating channel) increases from 22 to 24, the gain of the main lobe increases from 12 dBito 16 dBi.
Extended Data Fig. 5 Broadband 2π-phase control of topological beamformer’s radiating channel.
a Optical image of the taper region of the AB-type four-stage topological beamformer. Simulated b transmission and c phase of a single taper of the AB-type four-stage topological beamformer as a function of frequency and length L of the rectangular bar of the taper coupler. The transmission remains constant, while the phase undergoes a 2π variation across the entire bandwidth.
Extended Data Fig. 6 Broadband beamforming with three to eight beams.
a-f Measured and simulated radiation patterns at 0.331 THz (left panel) and measured broadband gain distributions (right panel) of the AB-type four-stage topological beamformers having three to eight radiating beams. The arrows in the left panel of a-f indicate the azimuthal angle position where the gain is measured in the right panel.
Extended Data Fig. 7 Reconfigurable photoswitching and control of the number of THz beams in 360° topological beamformer.
a Optical image of the 360° topological beamformer having six branches B1−B6. Each of the six branches transmits the THz signal into free space with a single radiated beam directed towards θB. Here θB = −120°, −60°, 0°, 60°, 120°, 180° is the orientation azimuthal angle of each branch. The ten markers centered at the domain wall denote the pump positions of a 525-nm continuous wave laser (diameter of the beam spot = 0.55 mm, pump power fluence = 902.9 Wcm−2). b Measured broadband radiation patterns of the 360° topological beamformer pumped at different positions P1 −P10.
Extended Data Fig. 8 Effect of pump fluence on the gain of topological beamformer.
a Measured gain of the THz beam radiated by the B2 branch of the 360° topological beamformer at different pump fluences. The topological beamformer is pumped at position P1 marked by a yellow circle in Extended Data Fig. 7a. b Measured gain at 0.3342 THz which is indicated by a dashed line in a.
Extended Data Fig. 9 Polarization analysis of topological beamformer.
a Schematic of the experimental configuration for polarization analysis. The THz wave radiated by the topological beamformer passes through a THz polarizer in free space and then is received by another topological beamformer. The THz polarizer is a wire grid polarizer consisting of an array of metal wires on a High-Density Polyethylene (HDPE) film. Such polarizers have > 95% transmission in the 300 GHz band which is the frequency range of interest in this work. The diameter of the available surface is 40 mm, and it is POL-HDPE-CA40-OD50.8-T8 from TYDEX optics. b Normalized OTA transmittance for different polarization angle α at 0.325 THz. Maximum power is received at α = 90° and a minimum power of 0.005 is reached at α = 0°. It indicates that the THz beam radiated from the topological beamformer is highly TE-polarized with a polarization purity of 99.5%.
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Wang, W., Tan, Y.J., Tan, T.C. et al. On-chip topological beamformer for multi-link terahertz 6G to XG wireless. Nature 632, 522–527 (2024). https://doi.org/10.1038/s41586-024-07759-5
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DOI: https://doi.org/10.1038/s41586-024-07759-5
