A&A 477, 345-352 (2008)
DOI: 10.1051/0004-6361:20078757
First results from a laboratory hypertelescope using single-mode fibers
F. Patru1, D. Mourard1, J.-M. Clausse1, L. Delage2, F. Reynaud2, M. Dubreuil1, D. Bonneau1, S. Bosio1, Y. Bresson1, Y. Hugues1, O. Lardière3, and A. Roussel11 Observatoire de la Côte d'Azur, Dpt. Gemini, UMR CNRS 6203, avenue Copernic, 06130 Grasse, France
e-mail: Denis.Mourard@obs-azur.fr
2 XLIM, Dpt. Photonique, UMR CNRS 6172, 123 avenue Albert Thomas, 87060 Limoges Cedex, France
3 Adaptive Optics Lab, Engineering Lab Wing B133, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
(Received 29 September 2007 / Accepted 19 October 2007)
Abstract
Context.In the future, giant optical interferometric arrays will be developed with
kilometric baselines and a large number of telescopes. Such arrays could have
direct imaging capabilities if optimized beam combiners are used.
Aims.This paper aims at studying the performance of an interferometric beam
combiner using single mode fibers and in the frame of a hypertelescope.
Methods.A laboratory testbed called SIRIUS was developed. We describe the general
concept, the technical specifications and the results obtained. These results
are analyzed with the help of a numerical simulator.
Results.Direct images were obtained at the densified focus of SIRIUS. We show that the
fibers greatly ease the pupil rearrangement. They also greatly improve the
quality and the stability of the direct image. The computed images allow us to
reproduce the effects of differential photometry and the influence of optical
path difference variations. Optical path difference errors less than
and differential photometries less than 60% are required to keep
the quality of the direct image.
Conclusions.These results demonstrate the great potential of direct imaging
interferometric beam combiners for future optical large arrays. The excellent
comparison between experience and simulation clearly shows the simplicity of
the fibered pupil densifier. It also gives us a great confidence in the
extrapolation of these results and specifications for future arrays with a very
large number of apertures.
Key words: instrumentation: high angular resolution -- instrumentation: interferometers -- telescopes -- methods: observational
© ESO 2007

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