Hexabundles: imaging fiber arrays for low-light astronomical applications

Joss Bland-Hawthorn*, Julia Bryant, Gordon Robertson, Peter Gillingham, John O'Byrne, Gerald Cecil, Roger Haynes, Scott Croom, Simon Ellis, Martin Maack, Peter Skovgaard, Danny Noordegraaf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

117 Citations (Scopus)


We demonstrate a novel imaging fiber bundle ("hexabundle") that is suitable for low-light applications in astronomy. The most successful survey instruments at optical-infrared wavelengths use hundreds to thousands of multimode fibers fed to one or more spectrographs. Since most celestial sources are spatially extended on the celestial sphere, a hexabundle provides spectroscopic information at many distinct locations across the source. We discuss two varieties of hexabundles: (i) lightly fused, closely packed, circular cores; (ii) heavily fused non-circular cores with higher fill fractions. In both cases, we find the important result that the cladding can be reduced to ∼2μm over the short fuse length, well below the conventional ∼10γ thickness employed more generally, with a consequent gain in fill factor. Over the coming decade, it is to be expected that fiber-based instruments will be upgraded with hexabundles in order to increase the spatial multiplex capability by two or more orders of magnitude.

Original languageEnglish
Pages (from-to)2649-2661
Number of pages13
JournalOptics Express
Issue number3
Publication statusPublished - 31 Jan 2011
Externally publishedYes


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