  The Large Binocular Telescope Interferometer (LBTI) can perform Fizeau
interferometry in the focal plane, which accesses spatial information out to
the LBT's full 22.7-m edge-to-edge baseline. This mode has previously been used
to obtain science data, but has been limited to observations where the optical
path difference (OPD) between the two beams is not controlled, resulting in
unstable fringes on the science detectors. To maximize the science return, we
are endeavoring to stabilize the OPD and tip-tilt variations and make the LBTI
Fizeau mode optimized and routine. Here we outline the optical configuration of
LBTI's Fizeau mode and our strategy for commissioning this observing mode.
