SPIRou at CFHT: fiber links and pupil slicer
Résumé
SPIRou is a near-IR (0.98-2.35μm) echelle spectropolarimeter / high precision velocimeter installed at the beginning of the year 2018 on the 3.6m Canada-France-Hawaii Telescope (CFHT) on Mauna Kea, Hawaii, with the main goal of detecting Earth-like planets around low mass stars and magnetic fields of forming stars. In this paper, the fiber links which connects the polarimeter unit to the cryogenic spectrograph unit (35 meter apart) are described. The pupil slicer which forms a slit compatible with the spectrograph entrance specifications is also discussed in this paper. Some challenging aspects are presented. In particular this paper will focus on the manufacturing of 35 meter fibers with a very low loss attenuation (< 13dB/km) in the non-usual fiber spectral domain from 0.98 μm to 2.35 μm. Other aspects as the scrambling performance of the fiber links to reach high accuracy radial velocity measurements (<1m/s) and the performances of the pupil slicer exposed at a cryogenic and vacuum environment will be discussed.