Thermal-Aware Placement and Routing for 3D Optical Networks-on-Chips

Many-core chip architectures integrate tens to hundreds of processor cores on a single chip. Recent development of photonic interconnects has made Optical Networks-on-Chips (ONoCs) an attractive technology to overcome the drawbacks of electrical networks-on-chips. With ultra-high bandwidth, low latency, and great energy efficiency, ONoCs enable the designer to build scalable systems. However, photonic devices are sensitive to temperature fluctuations, and hence, require proactive management. This paper first calculates the thermal distribution from cell distribution using an approximated Green's function and proposes a post-placement algorithm to reduce the number of photonic devices in the hotspots. The paper then improves the routing algorithm considering bending loss and temperature variations. Experimental results also verify the efficiency and effectiveness of our algorithm.