  As we move towards an era of hundreds of cores, the research community has
witnessed the emergence of opto-electronic network on-chip designs based on
nanophotonics, in order to achieve higher network throughput, lower latencies,
and lower dynamic power. However, traditional nanophotonics options face
limitations such as large device footprints compared with electronics, higher
static power due to continuous laser operation, and an upper limit on
achievable data rates due to large device capacitances. Nanoplasmonics is an
emerging technology that has the potential for providing transformative gains
on multiple metrics due to its potential to increase the light-matter
interaction. In this paper, we propose and analyze a hybrid opto-electric NoC
that incorporates Hybrid Plasmonics Photonics Interconnect (HyPPI), an optical
interconnect that combines photonics with plasmonics. We explore various
opto-electronic network hybridization options by augmenting a mesh network with
HyPPI links, and compare them with the equivalent options afforded by
conventional nanophotonics as well as pure electronics. Our design space
exploration indicates that augmenting an electronic NoC with HyPPI gives a
performance to cost ratio improvement of up to 1.8x. To further validate our
estimates, we conduct trace based simulations using the NAS Parallel Benchmark
suite. These benchmarks show latency improvements up to 1.64x, with negligible
energy increase. We then further carry out performance and cost projections for
fully optical NoCs, using HyPPI as well as conventional nanophotonics. These
futuristic projections indicate that all-HyPPI NoCs would be two orders more
energy efficient than electronics, and two orders more area efficient than
all-photonic NoCs.
