Laboratory characterization of FIRSTv2 photonic chip for the study of substellar companions

K. Barjot, E. Huby, S. Vievard, N. Cvetojevic, S. Lacour, G. Martin, V. Deo, V. Lapeyrere, D. Rouan, O. Guyon, J. Lozi, N. Jovanovic, C. Cassagnettes, G. Perrin, F. Marchis, G. Duchêne, T. Kotani

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


FIRST (Fibered Imager foR a Single Telescope instrument) is a post-AO instrument that enables high contrast imaging and spectroscopy at spatial scales below the diffraction limit. FIRST achieves sensitivity and accuracy by a unique combination of sparse aperture masking, spatial filtering by single-mode fibers and cross-dispersion in the visible. The telescope pupil is divided into sub-pupils by an array of microlenses, coupling the light into single-mode fibers. The output of the fibers are rearranged in a non redundant configuration, allowing the measurement of the complex visibility for every baseline over the 600-900 nm spectral range. A first version of this instrument is currently integrated to the Subaru Extreme AO bench (SCExAO). This paper focuses on the on-going instrument upgrades and testings, which aim at increasing the instrument's stability and sensitivity, thus improving the dynamic range. FIRSTv2's interferometric scheme is based on a photonic chip beam combiner. We report on the laboratory characterization of two different types of 5-input beam combiner with enhanced throughput. The interferometric recombination of each pair of sub-pupils is encoded on a single output. Thus, to sample the fringes we implemented a temporal phase modulation by pistoning the segmented mirrors of a Micro-ElectroMechanical System (MEMS). By coupling high angular resolution and spectral resolution in the visible, FIRST offers unique capabilities in the context of the detection and spectral characterization of close companions, especially on 30m-class telescopes.

Original languageEnglish (US)
Title of host publicationOptical and Infrared Interferometry and Imaging VII
EditorsPeter G. Tuthill, Antoine Merand, Stephanie Sallum
ISBN (Electronic)9781510636798
StatePublished - 2020
EventOptical and Infrared Interferometry and Imaging VII 2020 - Virtual, Online, United States
Duration: Dec 14 2020Dec 22 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical and Infrared Interferometry and Imaging VII 2020
Country/TerritoryUnited States
CityVirtual, Online


  • Exoplanets
  • High contrast imaging
  • Interferometry
  • Pupil remapping
  • Single-mode fiber filtering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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