Energy-Efficient Thermo-Optic Switches Enabled by 3D Glass-Based EIC–PIC Packaging for High-Density Photonic Switch Arrays

Thermo-optic (TO) switches are essential components in integrated photonic circuits (PICs), but their efficiency is limited by significant heat dissipation into the silicon substrate due to its high thermal conductivity. This study presents an energy-efficient TO switching solution based on 3D glass-based EIC–PIC packaging. By leveraging the low thermal conductivity of a glass interposer, the heater efficiency is significantly enhanced. Finite element simulations show that the hybrid-bonded PIC achieves a 3.43 times improvement in heater efficiency compared to conventional surface-mounted PICs, reaching 947.7 pm/mW. For a switch array with a through-glass via pitch of 100 μm, the normalized thermal crosstalk remains below 6% . The out-of-plane warpage is less than 1 μm for a 5 mm × 5 mm PIC. This 3D integration strategy provides a scalable and energy-efficient platform for high-density photonic switching, addressing key challenges in large-scale optical systems.