Stable non-volatile phase modulation with antimony-based phase shifter on a broadband silicon nitride platform

Silicon-based photonics is a leading platform for scalable and low-power photonic integrated circuits (PICs). However, conventional modulation methods suffer from high power consumption and volatility, particularly when using the silicon nitride platform. Phase change materials (PCMs) provide a compelling alternative, enabling nonvolatile and low-loss switching with a high refractive index contrast (Δn). In this work, we demonstrate, for the first time to the best of our knowledge, the integration of an n-doped polysilicon microheater to induce phase transitions in antimony selenide (Sb₂Se₃) on a silicon nitride (SiN_x) platform in the C-band. The device utilizes controlled electrical pulses to achieve a phase shift of 0.43π by switching Sb₂Se₃ between its amorphous and crystalline states over 7900 cycles, with an extinction ratio of up to 12.5 dB and a variation of ±1.9 dB over the entire 7900 cycles. These results highlight the potential scalability of this approach for broadband photonic switching applications that require nonvolatile functionality.