  In this communication is described a new type of Achromatic phase shifter
(APS) suitable for both nulling interferometry and coronagraphy, based on a
couple of crossed beamsplitter cubes, well-suited for equipping future
spaceborne instruments searching for extra-solar planets located in a habitable
zone. We present the general principle of this APS and discuss possible
implementations into a nulling coronagraph telescope or into a sparse-aperture
interferometer, either of the Fizeau or Michelson type. Expected performance in
terms of transmission maps and a preliminary tolerance analysis are also
provided. It turns out that the device is cheap, compact, and presents
reasonable manufacturing tolerances and costs

Instrumentation and Methods for Astrophysics;Optics