Multi-core integral field unit (MCIFUv2): fibre-link design and status

Abstract

The Multi-Core Integral Field Unit (MCIFU v2) is an add-on for the MagAO-X adaptive optics system, enabling spectroscopy and spectral differential imaging of close companions such as protoplanets and exoplanets in the Y, J, and H bands at R ∼ 5000. MagAO-X provides a diffraction-limited focal plane, which the MCIFU samples using a 117-spaxel fibre link that relays a ∼ 0.65 arcsec field of view to an external spectrograph. Two fibre links have been designed, one for Y+J (0.96-1.345 μm) and one for H (1.49-1.78 μm) bands, each consisting of a micro-lens array (MLA), a multi-core fibre (MCF), and a photonic reformatter, and this paper focuses on the Y+J implementation. The MLA enhances coupling efficiency into the MCF, whose heterogeneous core design is optimised using Coupled-Power Theory to minimise inter-core crosstalk. At the output, an ultrafast-laser-inscribed reformatter converts the hexagonal core layout into a linear slit with a simulated throughput of ∼ 66% and crosstalk below 6 × 10−4. The spectrograph then disperses all spaxels onto a HAWAII-2 detector. We present the first measurements of the fabricated MCF, confirming the predicted low crosstalk and compliance with the instrument requirement.

Authors 15

1. Sajjad Mahdizadeh

   Durham University

   Affiliation as printed

   Durham Univ. (United Kingdom)

2. R.J. Mears

   University of Bath

   Affiliation as printed

   Univ. of Bath (United Kingdom)

3. Nikoleta Zhekova

   University of Bath

   Affiliation as printed

   Univ. of Bath (United Kingdom)

4. Aurélien Benoît

   Heriot-Watt University

   Affiliation as printed

   Heriot-Watt Univ. (United Kingdom)

5. Sebastiaan Y. Haffert Aachen Leiden Univ. (Netherlands)

   Leiden University

   Affiliation as printed

   Leiden Univ. (Netherlands)

6. David G. MacLachlan

   Heriot-Watt University

   Affiliation as printed

   Heriot-Watt Univ. (United Kingdom)

7. Chiara D'Amato

   Politecnico di Milano

   Affiliation as printed

   Politecnico di Milano (Italy)

8. Viktoria Kutnohorsky

   Durham University

   Affiliation as printed

   Durham Univ. (United Kingdom)

9. Jared R. Males

   University of Arizona

   Affiliation as printed

   The Univ. of Arizona (United States)

10. Joshua Guy

    Durham University

    Affiliation as printed

    Durham Univ. (United Kingdom)

11. Olivier Guyon

    University of Arizona

    Affiliation as printed

    The Univ. of Arizona (United States)

12. Laird M. Close

    University of Arizona

    Affiliation as printed

    The Univ. of Arizona (United States)

13. Andrea Bianco

    Brera Astronomical Observatory

    Affiliation as printed

    INAF - Osservatorio Astronomico di Brera (Italy)

14. Robert R. Thomson

    Heriot-Watt University

    Affiliation as printed

    Heriot-Watt Univ. (United Kingdom)

15. T. A. Birks

    University of Bath

    Affiliation as printed

    Univ. of Bath (United Kingdom)