  We describe a resonantly enhanced Mach-Zehnder modulator (MZM) that can be
operated over a wide temperature range of 55C without being actively biased,
while providing a significant resonant enhancement of 6.8 at the nominal
wavelength / temperature compared to a linear MZM driven with a distributed
driver. More importantly, it enables a ~20X improvement in power consumption
compared to a 50 {\Omega} matched linear traveling wave modulator with
comparable phase shifter technology, drive voltage and output optical
modulation amplitude. Passive biasing of the Mach-Zehnder interferometer is
further implemented by replacing a splitter element in the MZM with a novel
device combining splitting and fiber coupling functionalities in a single,
multi-modal structure, that converts permanent fiber placement into a phase
correction. Both concepts are combined in a single modulator device, removing
the need for any type of active control in a wide temperature operation range.
