Development of an extremely coherent single-mode fiber bundle array for high-contrast imaging of extrasolar planets with visible Terrestrial Planet Finder

We report results from development of a prototype extremely coherent single mode fiber optic array for the TPF visible nulling interferometer. This device is used to negate the effects of residual stellar leakage (scattering) due to imperfections in the TPF telescope optics and the visible nulling interferometer optical train. This prototype consists of 10 X 10 single mode fibers, V-groove arrays, two lenslet arrays (one at the front end and the other at the back end) and auxiliary mechanical components. This first development will pave a clear path for making a final coherent fiber array with ~ 1000 fibers. The final array, once fully functional, should be able to improve image contrast by another ~ 3 orders of magnitude after 6-7 orders of magnitude star light subtraction using the visible nulling interferometer to allow detection of earth-like planets as close as 0.1 arcseconds around stars at ~ 10 pc in space with a 4m size TPF. This concept combines all the advantages of a nulling interferometer with the simplicity of a modest size and modest optical quality single aperture telescope, which allows tremendous reduction of the total cost and simplicity of the operation of a visible TPF over other TPF approaches. This fiber array can also be used in the visible coronagraph for rejecting scattered light.