Topological Berry Antenna on a Silicon Chip for Terahertz Wireless Communication

Abstract

Nonzero Berry curvature is central to the existence of topological edge states in electronic and photonic valley-Hall systems. While manipulating the Berry curvature in condensed matter systems is challenging, valley-Hall topological photonics offer unprecedented control, where the broken spatial inversion symmetry alters the Berry curvature. Herein, an all-silicon Berry antenna is presented, using a continuously varying geometry corresponding to a gradual change in Berry curvature. The on-chip topological edge mode with a tunable field extent is achieved to enhance effective antenna aperture, creating a high-gain on-chip photonic antenna with perfectly planar wavefronts. Experimentally, a maximum gain of 17 dBi that supports 20 Gbps chip-to-chip wireless communication is demonstrated, with active optical tunability of the antenna gain with modulation depths of 8 dBi. This Berry antenna paves the way for the development of complementary metal-oxide-semiconductor (CMOS) compatible topological Berry devices, with potential applications in integrated micro-/nano-photonics, next-generation wireless communications (6G to Xth generation), and terahertz detection and ranging.