  Lowering the operating voltage of electrooptic modulators is desirable for a
variety of applications, most notably in analog photonics , and digital data
communications . In particular for digital systems such as CPUs, it is
desirable to develop modulators that are both temperature-insensitive and
compatible with typically sub-2V CMOS electronics ; however, drive voltages in
silicon-based MZIs currently exceed 6.5V . Here we show an MZI modulator based
on an electrooptic polymer-clad silicon slot waveguide, with a halfwave voltage
of only 0.69V, and a bandwidth of 500 MHz. We also show that there are also
paths to significantly improve both the bandwidth and drive voltage . Our
silicon-organic modulator has an intrinsic power consumption less than 0.66
pJ/bit, nearly an order of magnitude improvement over the previous lowest
energy silicon MZI .
