Broadband Nonvolatile Electrically Controlled Programmable Units in Silicon Photonics

Programmable photonic integrated circuits (PICs) have recently gained significant interest due to their potential in creating next-generation technologies ranging from artificial neural networks and microwave photonics quantum information processing. The fundamental building block of such programmable PICs is a tunable 2 x switch, traditionally controlled by the thermo-optic or free-carrier dispersion. Yet, these implementations are power-hungry, volatile, large footprint (typically > 100 um). Therefore, truly 'set-and-forget' type switch with zero static power consumption highly desirable for large-scale PICs. Here, we report broadband nonvolatile electrically silicon based on phase-change material Ge2Sb2Te5. directional coupler exhibits compact coupling length (64 um), small insertion loss (<2 dB), minimal crosstalk (<-8 dB) across entire telecommunication C-band while maintaining record-high endurance over 2,800 switching cycles. This demonstrated constitutes critical component realizing future generic systems.