  Electro-optic modulation performs a technological relevant functionality such
as for communication, beam steering, or neuromorphic computing through
providing the nonlinear activation function of a perceptron. Wile Silicon
photonics enabled the integration and hence miniaturization of optoelectronic
devices, the weak electro-optic performance of Silicon renders these modulators
to be bulky and power-hungry compared to a single switch functionality known
from electronics. To gain deeper insights into the physics and operation of
modulators hetero-generous integration of emerging electro-optically active
materials could enable separating light passive and low-loss light routing from
active light manipulation. Here we discuss and review our recent work on a)
fundamental performance vectors of electro-optic modulators, and b) showcase
recent development of heterogeneous-integrated emerging EO materials into
Si-photonics to include an ITO-based MZM, a Graphene hybrid-plasmon and the
first TMD-MRR modulator using a microring resonator. Our results indicate a
viable path for energy efficient and compact Silicon photonic based modulators.
