  Electro-optic modulators provide a key function in optical transceivers and
increasingly in photonic programmable Application Specific Integrated Circuits
(ASICs) for machine learning and signal processing. However, both foundry ready
silicon based modulators and conventional material based devices utilizing
Lithium niobate fall short in simultaneously providing high chip packaging
density and fast speed. Current driven ITO based modulators have the potential
to achieve both enabled by efficient light matter interactions. Here, we
introduce micrometer compact Mach Zehnder Interferometer (MZI) based modulators
capable of exceeding 100 GHz switching rates. Integrating ITO thin films atop a
photonic waveguide, spectrally broadband, and compact MZI phase shifter.
Remarkably, this allows integrating more than 3500 of these modulators within
the same chip area as only one single silicon MZI modulator. The modulator
design introduced here features a holistic photonic, electronic, and RF-based
optimization and includes an asymmetric MZI tuning step to optimize the
Extinction Ratio (ER) to Insertion Loss (IL) and dielectric thickness sweep to
balance the tradeoffs between ER and speed. Driven by CMOS compatible bias
voltage levels, this device is the first to address next generation modulator
demands for processors of the machine intelligence revolution, in addition to
the edge and cloud computing demands as well as optical transceivers alike.
