Nulling interferometer based on an integrated optics combiner

The Multi-Aperture Imaging Interferometer (MAI 2 ), which Alcatel Space has been developing for ESA for deep nulling demonstration in preparation of the Darwin project, is based on an innovative layout, where both beam combination and modal wave-front filtering functions are achieved by means of an Integrated Optics (IO) component. Two different components, based on different designs and technologies, have been developed and characterised by LAOG with detailed design and manufacturing performed by IMEP/GeeO/LETI. SAGEIS-CSO (optical path control) and Alcatel Space have developed the other breadboard functions. The MAI² interferometer achieved stable Darwin-class nulling (10-5) of a simulated star in monochromatic light, and with a relative bandwidth of several percent (10-4). Operation in non-polarised light, with unchanged nulling performances, was also demonstrated. Preliminary characterisation of the relationship between nulling and bandwidth is also provided.