Calibration of silica fibers for the Optical Hawaiian Array for Nanoradian Astronomy (`OHANA): Temperature dependence of differential chromatic dispersion

Sébastien Vergnole (1) , Takayuki Kotani (2, 3, 4) , Guy Perrin (2, 3) , L. Delage (1) , Francois Reynaud (1)

1 IRCOM - Institut de Recherche en Communications Optiques et Microondes
2 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
3 Pôle Astronomie du LESIA
4 Department of Astronomy, School of Science, University of Tokyo

In the frame of the Optical Hawaiian Array for Nanoradian Astronomy (`OHANA) project, 300-m long silica fibers are necessary to coherently link the Canada France Hawaii and Gemini telescopes. In this paper, we report measurements of the differential chromatic dispersion between two 300-m long silica polarization maintaining fibers for the astronomical J band (1.10 1.40 mum) as a function of the temperature variation on one fiber arm of the interferometer. We demonstrate that the second order coefficient of chromatic dispersion increases linearly with the temperature. Consequently, we propose two methods to compensate this additional and variable differential chromatic dispersion: the first one using a dispersive optical fiber delay line and the second one using a set of CaF₂ bulk plates.

Domaines: Astrophysique [astro-ph]

Sébastien Vergnole, Takayuki Kotani, Guy Perrin, L. Delage, Francois Reynaud. Calibration of silica fibers for the Optical Hawaiian Array for Nanoradian Astronomy (`OHANA): Temperature dependence of differential chromatic dispersion. Optics Communications, 2005, 251, pp.115-123. ⟨10.1016/j.optcom.2005.02.077⟩. ⟨hal-03785789⟩