Published on 03 Jul 2022

Terahertz Topological Photonics for On-Chip Communication

Web of Science's Hot Paper by Assoc Prof Ranjan Singh


The terahertz (THz) frequency region, lying at the convergence of electronics and photonics, is key to the development of 6G communications and Internet-Of-Things (IoT) platforms due to the large bandwidth and the high data rates of up to 1 terabit per second (Tbps) that it offers.  THz technology is therefore the next frontier of communication technology and can enable networks with ultra-high data rates and low latency.

To usher the world into this new era of connectivity, that will unify the digital, physical, and biological worlds, an all-silicon on-chip integrated platform capable of operating at THz frequencies to enable low-loss, energy-efficient, and high-speed interchip links is vital. However, fabrication defects and bending losses limit the size and efficiency of conventional devices designed to work at these frequencies.

The article published in Nature Photonics presents a high-speed silicon photonic topological insulator (PTI) chip that can transmit THz waves resulting in a data rate of 11 gigabits per second (Gbit/s), exceeding the theoretical limit of 10 Gbit/s for 5G communications. The breakthrough of this silicon topological chip is that it can transmit signals error-free even around several sharp bends inside the chip. This technology could be the steppingstone for the next generation ‘6G communication with Tbps speed’ and will set a new paradigm for on-chip communication with the most recent results from Assoc Prof. Ranjan Singh’s lab showing data communication speeds exceeding 150 Gbit/s.

Assoc Prof Ranjan Singh and his team present the principles of PTI waveguide design and experimentally demonstrate high-speed data transfer by the error-free transmission of uncompressed 4k high-definition video. Furthermore, the all-silicon platform simplifies integration with conventional electronic devices. This along with the compact nature of the platform will enable widespread adoption of THz technology in the future. The article has therefore inspired research on how the concepts of PTI can be used to develop compact all-Si devices that can be seamlessly integrated into applications like THz sensing, THz imaging, and 6G communications.

Simulated |Hz| field distribution (colour scale) in the onchip VPC.


Yang YH, Yamagami Y, Yu XB, Pitchappa P, Webber J, Zhang BL, Fujita M, Nagatsuma T, Singh R, “ Terahertz Topological Photonics for On-Chip Communication ”,  Nature Photonics, 14,  446–451 (2020), DOI 10.1038/s41566-020-0618-9

Web of Science’s Hot Paper | 181 Citations (as of 4 July 2022)