High-Contrast, Narrow-Field Imaging with a Multi-Aperture Telescope

The direct detection of faint planetary companions to bright nearby stars calls for the development of high-contrast narrow-field detection techniques. A number of novel coronagraphic approaches aimed at filling this niche have recently been proposed, but this challenging observational goal may also call for the development of novel types of telescope architecture. As discussed here, one approach to high-contrast narrow field imaging involves replacing the monolithic telescope assembly by an array of small "sub-aperture" telescopes, with the final pupil being assembled by means of a single-mode fiber array. Such an approach can potentially greatly relax the volume, mass and cost constraints thought to apply to large and accurately-figured monolithic telescopes. However, the suggested approach relies on the use of a well-matched, low-dispersion, single-mode fiber array. Classical single mode fibers would require dispersion correction to match pathlengths, but the new generation of photonic fibers, with design-selectable parameters, may ease this issue.