Design of Reconfigurable On-Chip Optical Architectures based on Phase Change Material

Integrated optics is a promising technology to take the advantage of light propagation for high throughput chip-scale computing architectures and interconnects. Optical devices call for reconfigurable architectures to maximize resource utilization. Typical reconfigurable optical computing architectures involve micro-ring resonators for electro-optic modulation. However, such devices require voltage and thermal tuning to compensate for fabrication process variability and thermal sensitivity. To tackle this challenge we propose to use non-volatile Phase Change Material (PCM) to configure optical path. The non-volatility of PCM elements allows maintaining the optical path without consuming energy and the high contrast between two state of crystalline (cr) and amorphous (am) allows to route signal only through the required resonators, thus saving the calibration energy of bypassed resonators. We evaluate the efficiency of PCM based design on Reconfigurable Directed Logic (RDL) and nanophotonic interconnect. We develop a model allowing to estimate optical and electrical energy consumption. In the context of nanophotonic interconnect we evaluate the efficiency of the proposed PCM-based interconnects using system level simulations carried out with SNIPER manycore simulator. Results show that the proposed implementation allows reducing the static power by 53% on average for RDL and communication power saving up to 52% is achieved for nanophotonic interconnect