Nonvolatile Reconfigurable Phase-change-materials Integrated Silicon Photonics

The emergence of integrated photonic technology provides an attractive solution of high speed, broad bandwidth and strong parallelism for large-scale information transmission and processing in interconnection, communication and computing. Reconfigurability is necessary for photonic processors to adapt varieties of application scenarios in the fields of data exchange, microwave photonics and neural networks. As yet, thermo-optical effect and carrier plasma dispersion effect are the most common phenomena for optical modulation. However, the volatility not only requires continuous power supply to maintain the devices’ state, but also accompanies with serious thermal crosstalk induced by active regions. Hence, the nonvolatile methods that can reconfigure and fix on the current state for a long time after a single external excitation are considered as one of the significant technologies in the next generation of integrated photonics. Nonvolatile reconfiguration has been achieved through trapped-charge effect, bistable micro-electromechanical system (MEMS) with nano-latch mechanism and ferroelectric materials, which suffer from high loss, lower stability and complex process flow. Chalcogenide phase change materials (PCM) have become a promising method to realize compact and nonvolatile reconfigurable integrated photonic devices due to the high optical constant contrast between amorphous state and crystalline state, superiorly stable property and low temperature deposition possibility. Here, we developed a monolithic back-end-of-line integration technology of PCM in silicon photonics, supporting "Zero-change" heterogeneous integration platform at wafer scale. On this basis, nonvolatile integrated photonic devices with excellent performance have been fabricated. It lays a foundation for improving the energy efficiency and integration density of integrated photonic processors and suppressing thermal crosstalk between integrated photonic devices.