  In this paper are discussed the nulling and imaging properties of monolithic
pupil telescopes equipped with a focal plane waveguide array, which could be
envisaged as precursor space missions for future nulling interferometers or
coronagraphs searching for habitable planets outside of our solar system. Three
different concepts of nulling telescopes are reviewed, namely the
Super-Resolving Telescope (SRT) having multiple, non-overlapping exit
sub-apertures and the Sheared-Pupil Telescope (SPT), either unmasked or masked
with a Lyot stop placed at its exit pupil plane. For each case simple
theoretical relationships allowing to estimate the nulling rate,
Signal-to-Noise Ratio (SNR) and Inner Working Angle (IWA) of the telescope are
established or recalled, and numerical simulations are conducted. The
preliminary results of this study show that the most promising designs should
either be a SRT of high radiometric efficiency associated with an adequate
leakage calibration procedure, or a masked SPT with potentially deeper nulling
rates but lower SNR, depending on what kind of performance is to be preferred.
