Broadband and High-Efficiency Optical Switch using Waveguide Superlattices with Artificial Gauge Field at 2-Micron

The 2 μm waveband has emerged as a promising transmission window for next-generation low-loss, low-latency optical communication. Thermo-optic modulators and switches serve as indispensable fundamental building blocks for large-scale and programmable photonic integrated circuits. Here, we experimentally demonstrate a broadband and high-efficiency silicon thermo-optic Mach–Zehnder switch enabled by waveguide superlattices with artificial gauge field. By applying a sinusoidal modulation profile to the binary waveguide array, low-crosstalk and broadband light propagation can be effectively realized. Benefiting from geometric topology optimization, the presented design achieves the lowest power consumption of 2.17 mW at this wavelength without resorting additional thermal isolation, along with a low insertion loss of 1.5 dB, and maintains crosstalk below −22 dB across the broadest operation bandwidth of 110 nm within the 2 μm waveband. With such superior overall performance and excellent scalability, the proposed thermo-optic switch holds great potential for advancing next-generation large-scale photonic integrated circuits in the 2 μm waveband and beyond.