Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble

Figure 11.6: Left: Integrated optics two-telescope beam combiner for the VINCI instrument of the VLTI.
Right: first fringes obtained with the Auxiliary Telescopes of the VLTI on HD 62082 by means of the integrated
optics beam combiner in the K band (ESO Press Release 06/05).
11.2.4 Instrumental Research and development activities
Lab workbenches IONIC passed and future on-sky experiments rely on a intensive laboratory effort whose
aim is to characterize as much as possible all the performances in lab before any shipment. This has required
the development of new testbeds such as an industrial level connectorization bench to plug fiber V-grooves to
integrated optics chips, or a full VLTI 8-telescope simulator (Jocou et al., 2004, SPIE, 5491, 1351).
An infrared camera dedicated to these interferometric workbenches has been fully developed in LAOG in
collaboration with the LESIA (Observatoire de Paris) for the clock sequencer. This camera uses a PICNIC
infrared array produced by the Rockwell Science Center in the US. The main features of this detector are:
256x256 pixels of 24 µm size, sensitive to the [0.9 µm; 2.5 µm] range, CMOS technology allowing multiple
non-destructive readout and image windowing, readout noise of about 40 e − . Such a lab camera is required for
the Vitruv demonstrator as well as for measuring interferometric signals coming from a 8-telescope combiner.
The PICNIC camera is currently under its final tests: the cryogenics and the readout electronics sub-systems
were successfully accepted, the first images of the whole system at cold temperature using the ”MUX” was
recently obtained (electrical model of the detector used to debug the system before using the science grade
detector). This camera will be delivered to the laboratory before the end of 2005.
Integrated optics for DARWIN: MAII, IODA LAOG is involved in R&D programs dedicated to the
preparation of the ESA DARWIN mission (Léger et al., 1996, A&SS, 241(1), 135). This mission is aimed at
discovering life on Earth-like exoplanets and therefore is extremely challenging on the technical side. One of
the most critical concerns is the ability in this nulling experiment to perform the most efficient modal filtering
to achieve very high dynamic range and main star extinction mandatory for detection of Earth-like planets. In
this context, single-mode waveguides have been identified as one of the most promising solutions (Ménesson et
al., 2002, JOSA, 19(3), 596). On this basis of its expertise in integrated optics for interferometry, LAOG has
contributed to three ESA R&D contracts dedicated to the DARWIN mission by:
• providing the integrated optics beam combiner of a nulling bench in the H band in the framework of
the Multi Aperture Imaging Interferometer, (MAII, an ESA contract). The project under direction of
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