# Terahertz topological photonics for on-chip communication

## TL;DR

This paper demonstrates robust terahertz topological valley transport on silicon chips, enabling high-speed, error-free on-chip communication with minimal losses even through sharp bends, advancing THz communication technology.

## Contribution

It provides the first experimental demonstration of topological phases of THz waves on silicon chips, showcasing robust valley transport for high-speed on-chip data transmission.

## Key findings

- Unity transmission over a bulk band gap after ten sharp corners
- Error-free data transmission at 10 Gbit/s
- Successful uncompressed 4K video transmission

## Abstract

The computing speeds in modern multi-core processors and big data servers are no longer limited by the on-chip transistor density that doubles every two years following the Moores law, but are limited by the on-chip data communication between memories and microprocessor cores. Realization of integrated, low-cost, and efficient solutions for high speed, on-chip data communications require terahertz (THz) interconnect waveguides with tremendous significance in future THz technology including THz-wave integrated circuits and THz communication. However, conventional approaches to THz waveguiding suffer from sensitivity to defects and considerable bending losses at sharp bends. Here, building on the recently-discovered topological phase of light, we experimentally demonstrate robust THz topological valley transport on low-loss, all-silicon chips. We show that the valley polarized topological kink states exhibit unity transmission over a bulk band gap even after propagating through ten sharp corners. Such states are excellent information carriers due to their robustness, single-mode propagation, and linear dispersion-key properties for next generation THz communications. By leveraging the unique properties of kink states, we demonstrate error-free communication through a highly-twisted domain wall at an unprecedented data rate (10 Gbit/s) and uncompressed 4K high-definition video transmission. Our work provides the first experimental demonstration of the topological phases of THz wave, which could certainly inspire a plethora of research on different types of topological phases in two and three dimensions.

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Source: https://tomesphere.com/paper/1904.04213