  Here, we experimentally demonstrate an Indium Tin Oxide (ITO) Mach-Zehnder
interferometer heterogeneously integrated in silicon photonics. The phase
shifter section is realized in a novel lateral MOS configuration, which, due to
favorable electrostatic overlap, leads to efficient modulation (V{\pi}L = 63
Vum). This is achieved by (i) selecting a strong index changing material (ITO)
and (ii) improving the field overlap as verified by the electrostatic field
lines. Furthermore, we show that this platform serves as a building block in an
endfire silicon photonics optical phased array (OPA) with a half-wavelength
pitch within the waveguides with anticipated performance, including narrow main
beam lobe (<3{\deg}) and >10 dB suppression of the side lobes, while
electrostatically steering the emission profile up to plus/minus 80{\deg}, and
if further engineered, can lead not only towards nanosecond-fast beam steering
capabilities in LiDAR systems but also in holographic display, free-space
optical communications, and optical switches.
