POPSTAR: a Robust Modular Optical NoC Architecture for Chiplet-based 3D Integrated Systems.

Silicon photonics technology is now gaining maturity with increasing levels of design complexity from devices to large photonic integrated circuits. Close integration of control electronics with 3D assembly of photonics and CMOS opens the way to high-performance computing architectures partitioned in chiplets connected by optical NoC on silicon photonic interposers. In this paper, we give an overview of our works on optical links and NoC for manycore systems, from low-level control of photonic devices to high-level system optimization of the optical communications. We detail the POPSTAR optical NoC topology and architecture (Processors On Photonic Silicon interposer Terascale ARchitecture) with electro-optical interface chiplets, the corresponding nested spiral topology for single-writer multiple- reader links and the associated control electronics, in charge of high-speed drivers, thermal stabilization and handling of the protocol stack, from data integrity to flow-control, routing and arbitration of the optical communications. The strengths and opportunities for this architecture will be discussed, with a shift in system & implementation constraints with respect to previous optical NoC proposals, and new challenges to be addressed.