Multi-core fiber-fed integral field spectrograph (MCIFU)-III: An ultrafast laser inscribed photonic reformatter and mask

Fraser A. Pike, Aurelien Benoit, David G. MacLachlan, Calum A. Ross, Robert J. Harris, Sebastiaan Y. Haffert, Itandehui Gris-Sanchez, Timothy A. Birks, Robert R. Thomson

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

4 Citations (Scopus)
36 Downloads (Pure)


We report on the conception and the fabrication of a 3D photonic reformatter of 73 waveguides and its associated opaque mask in a wide collaboration to develop a multi-core fiber-fed integral field spectrograph (MCIFU) centered on the Jband. The reformatter is a 3D structure that light from the input quasi-hexagonal multicore fiber is spread out by rearrangement to avoid individual core spectra overlapping when the light is dispersed. The reformatter is fabricated using ultrafast laser inscription (ULI) in a borosilicate glass of 20 mm length. Using a similar ULI process, a 73-hole mask was fabricated in silica glass that precisely matched the waveguides at the output of the reformatter. The output surface of the mask was coated with a 120 nm layer of chromium to block scattered light generated in the bulk material and enhance the signal-To-noise. All inscribed waveguides, characterized using a stable laser centered at 1310 nm from the multicore fiber to the output mask, present consistent single-mode output behavior with a maximum throughput exceeding 60%. Over the 73 cores, the average throughput was measured at 40%. First observations of the full MCIFU device during on-sky measurements have shown promising results to the potential of this novel fiber integral field unit.

Original languageEnglish
Title of host publicationAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV
EditorsRamon Navarro, Roland Geyl
ISBN (Electronic)9781510636903
ISBN (Print)9781510636897
Publication statusPublished - 13 Dec 2020
EventSPIE Astronomical Telescopes + Instrumentation 2020 - Virtual, Online, United States
Duration: 14 Dec 202022 Dec 2020

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE Astronomical Telescopes + Instrumentation 2020
Country/TerritoryUnited States
CityVirtual, Online


  • Astrophotonics
  • Exoplanets
  • High contrast imaging.
  • Integral field spectroscopy
  • Multi-core fiber
  • Photonic reformatter
  • Ultrafast Laser Inscription
  • Waveguides

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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