Photonic Supercoupling in Silicon Topological Waveguides
Ridong Jia, Yi Ji Tan, Nikhil Navaratna, Abhishek Kumar, Ranjan Singh
Abstract
Abstract 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. A supercoupled integrated chip is developed, realizing a 91% coupling ratio and a −30 dB isolation over 2.8λ waveguide separations simultaneously. Supercoupled devices are further showcased including a waveguide‐cavity system with 3.2λ excitation distance, and a waveguide directional supercoupler with a compact coupling area of nearly λ 2 /4, which outperform conventional devices. Supercoupling provides new degrees of freedom for optimizing coupling and isolation between photonic integrated components, facilitating new applications in on‐chip sensing, lasing, and telecommunications.