Artificial gauge field based thermo-optic phase shifter enabling low power consumption and broadband operation

Thermo-optic phase shifters are cornerstones in large-scale silicon photonic systems, yet their practical deployment is hindered by a persistent trade-off between power efficiency and compact broadband operation. Here, we break this trade-off using an artificial-gauge-field (AGF) design that permits dense waveguide folding without incurring crosstalk penalties-a key enabler for high-density photonic integration. Fabricated on a standard 220-nm SOI platform, our devices achieve π-phase-shift powers of 3.4 mW (7-fold) and 4.2 mW (5-fold) within a footprint of only 200 × 10 μm². Across the S + C + L band (1480-1600 nm), the phase shifters maintain >15 dB extinction ratio with flat tuning response, ensuring wavelength-independent operation for multi-band systems. Moreover, devices tolerate ±20 nm fabrication variations without performance degradation, demonstrating CMOS-compatible manufacturability.