Title 3D free-form optical lens — miniaturised fibre couplers for astrophotonics
Authors Mu, Haoran ; Smith, Daniel ; Katkus, Tomas ; Le, Nguyen Hoai An ; Stonytė, Dominyka ; Gailevičius, Darius ; Kapsaskis, Dan ; Frate, Alexander Del ; Bedi, Talwinder Singh ; Narbutis, Donatas ; Anand, Vijayakumar ; Astrauskytė, Darija ; Grinevičiūtė, Lina ; Ng, Soon Hock ; Glazebrook, Karl ; Lawrence, Jon ; Juodkazis, Saulius
DOI 10.1016/j.optlastec.2025.112960
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Is Part of Optics & laser technology.. Elsevier. 2025, vol. 190, art. no. 112960, p. 1-13.. ISSN 0030-3992. eISSN 1879-2545
Keywords [eng] micro-optics ; fibre couplers ; etendue matching ; laser ablation ; crystal optics
Abstract [eng] In astronomy, multi-object spectrographs employ fibre positioning robots to couple the light from multiple astronomical sources (stars or galaxies) into multiple multi-mode fibres, which are distributed across the focal plane of the telescope. These fibres transport the celestial light to the entrance slit of a spectrograph (or bank of spectrographs) for analysis. For any multi-object system, mm-scale opto-mechanical solutions are required to couple the telescope light efficiently into the fibre. We demonstrate a unique micro( μ )-optics solution to replace current optical fibre couplers. Specifically, we target technology on board the Keck telescope’s FOBOS - Fibre-Optic Broadband Optical Spectrograph — which operates at UV to IR spectral ranges. For spectrally broadband UV-IR band operation, we use glass and crystals: fused silica, crystalline quartz (transparency 0 . 16 − 2 μ m ), sapphire Al2O3 ( 0 . 2 − 5 μ m ), CaF 2 ( 0 . 2 − 7 μ m ), and BaF 2 ( 0 . 2 − 10 μ m ). The miniaturised μ -coupler is monolithic, with the entire light path contained within glass or crystal, seamlessly extending to the fibre entrance, which is laser-machined and precisely aligned with the optical axis.
Published Elsevier
Type Journal article
Language English
Publication date 2025
CC license CC license description