Broadband Nonvolatile Electrically Controlled Programmable Units in Silicon Photonics

Programmable photonic integrated circuits (PICs) have recently gained significant interest because of their potential in creating next-generation technologies ranging from artificial neural networks and microwave photonics to quantum information processing. The fundamental building block of such programmable PICs is a 2 x 2 programmable unit, traditionally controlled by the thermo-optic or free-carrier dispersion. However, these implementations are power-hungry and volatile and have a large footprint (typically >100 mu m). Therefore, a truly set-and-forget-type 2 x 2 programmable unit with zero static power consumption is highly desirable for large-scale PICs. Here, we report a broadband nonvolatile electrically controlled 2 x 2 programmable unit in silicon photonics based on the phase-change material Ge2Sb2Te5. The directional coupler-type programmable unit exhibits a compact coupling length (64 mu m), small insertion loss (similar to 2 dB), and minimal crosstalk (<-8 dB) across the entire telecommunication C-band while maintaining a record-high endurance of over 2800 switching cycles without significant performance degradation. This nonvolatile programmable unit constitutes a critical component for realizing future generic programmable silicon photonic systems.

Automated summary

Programmable photonic integrated circuits (PICs) have recently gained significant interest due to their potential in next-generation technologies. The fundamental building block is a 2 x 2 programmable unit, traditionally controlled by thermal or free-carrier dispersion. However, these implementations are power-hungry and volatile, making a set-and-forget-type unit with zero static power consumption highly desirable. This report presents a nonvolatile electrically controlled 2 x 2 programmable unit in silicon photonics, which exhibits compact size, low insertion loss, and minimal crosstalk.