Design and evaluation of an arbitration-free passive optical crossbar for on-chip interconnection networks

With recent advances in silicon nanophotonics, optical crossbars based on CMOS-compatible microring resonators have emerged as viable on-chip optical interconnection networks to deliver high-bandwidth communication at low power dissipation with a small footprint. This paper describes the design, fabrication and evaluation of an arbitration-free passive crossbar based on a microring resonator matrix that can be used to route wavelength division multiplexing (WDM) signals across the chip. The salient feature of the proposed design is the ability to support multicasting and many-to-one communication efficiently (without arbitration), which makes it suitable for implementing cache coherency protocols and on-chip interconnect in future many-core processors.