  Electrooptic modulation performs the conversion between the electrical and
optical domain with applications in data communication for optical
interconnects, but also for novel optical compute algorithms such as providing
nonlinearity at the output stage of optical perceptrons in neuromorphic
analogue optical computing. Since the clock frequency for photonics on chip has
a power overhead sweet slot around 10s of GHz, ultrafast modulation may only be
required in long distance communication, but not for short onchip links. Here
we show a roadmap towards atto Joule per bit efficient modulators on chip as
well as some experimental demonstrations of novel plasmon modulators with sub
1fJ per bit efficiencies. We then discuss the first experimental demonstration
of a photon plasmon-hybrid Graphene-based electroabsorption modulator on
silicon. The device shows a sub 1V steep switching enabled by near ideal
electrostatics delivering a high 0.05dB per V um performance requiring only 110
aJ per bit. Improving on this design, we discuss a plasmonic slot based
Graphene modulator design, where the polarization of the plasmonic mode matches
with Graphenes inplane dimension. Here a push pull dual gating scheme enables
2dB per V um efficient modulation allowing the device to be just 770 nm short
for 3dB small signal modulation. This in turn allows for a device-enabled two
orders of magnitude improvement of electrical optical co integrated network on
chips over electronic only architectures. The latter opens technological
opportunities in in cognitive computing, dynamic data-driven applications
system, and optical analogue compute engines to include neuromorphic photonic
computing.
