Photonic Supercoupling in Silicon Topological Waveguides.

Waveguide interconnect coupling control is essential for enhancing the chip density of photonic integrated circuits to incorporate a growing number of components. However, a critical engineering challenge is to achieve both strong waveguide isolation and efficient long-range coupling on a single chip. Here, a novel photonic supercoupling phenomenon is demonstrated for waveguide coupling over separation distances from a quarter to five wavelengths (λ), leveraging the tunable mode tails and the vortex energy flow in topological valley Hall system.

On-chip topological beamformer for multi-link terahertz 6G to XG wireless.

Terahertz (THz) wireless communication holds immense potential to revolutionize future 6G to XG networks with high capacity, low latency and extensive connectivity. Efficient THz beamformers are essential for energy-efficient connections, compensating path loss, optimizing resource usage and enhancing spectral efficiency. However, current beamformers face several challenges, including notable loss, limited bandwidth, constrained spatial coverage and poor integration with on-chip THz circuits.

150 Gbps THz Chipscale Topological Photonic Diplexer.

Photonic diplexers are being widely investigated for high data transfer rates in on-chip communication. However, dividing the available spectrum into nonoverlapping multicarrier frequency sub-bands has remained a challenge in designing frequency-selective time-invariant channels. Here, an on-chip topological diplexer is reported exhibiting terahertz frequency band filtering through Klein tunneling of topological edge modes.

Slow light topological photonics with counter-propagating waves and its active control on a chip.

Topological slow light exhibits potential to achieve stopped light by virtue of its widely known robust and non-reciprocal behaviours. Conventional approach for achieving topological slow light often involves flat-band engineering without disentangling the underlying physical mechanism. Here, we unveil the presence of counter-propagating waves within valley kink states as the distinctive hallmark of the slow light topological photonic waveguides.

Valley-conserved topological integrated antenna for 100-Gbps THz 6G wireless.

The topological phase revolutionized wave transport, enabling integrated photonic interconnects with sharp light bending on a chip. However, the persistent challenge of momentum mismatch during intermedium topological mode transitions due to material impedance inconsistency remains. We present a 100-Gbps topological wireless communication link using integrated photonic devices that conserve valley momentum.

Interfacial topological photonics: broadband silicon waveguides for THz 6G communication and beyond.

Topological photonics has expanded our understanding of electromagnetic wave propagation and unraveled new methods of electromagnetic wave shaping. Among the various topological photonic systems, valley photonic crystal (VPC) is a highly versatile platform for constructing interfaces that supports unidirectional edge state to enable the robust topological transport of light. Although silicon VPC waveguides has demonstrated the lossless propagation of terahertz (THz) waves through multiple sharp bends, existing designs are mostly based on the standard zigzag-interface.

Self-adaptive deep reinforcement learning for THz beamforming with silicon metasurfaces in 6G communications.

Exponential growth in data rate demands has driven efforts to develop novel beamforming techniques for realizing massive multiple-input and multiple-output (MIMO) systems in sixth-generation (6G) terabits per second wireless communications. Existing beamforming techniques rely on conventional optimization algorithms that are too computationally expensive for real-time applications and require complex digital processing yet to be achieved for phased array antennas at terahertz frequencies. Here, we develop an intelligent and self-adaptive beamforming scheme enabled by deep reinforcement learning, which can predict the spatial phase profiles required to produce arbitrary desired radiation patterns in real-time.

Space-Time Wave Packets from Smith-Purcell Radiation.

Space-time wave packets are electromagnetic waves with strong correlations between their spatial and temporal degrees of freedom. These wave packets have gained much attention for fundamental properties like propagation invariance and user-designed group velocities, and for potential applications like optical microscopy, micromanipulation, and laser micromachining. Here, free-electron radiation is presented as a natural and versatile source of space-time wave packets that are ultra-broadband and highly tunable in frequency.