Long-term stability of fibre-optic transmission for multi-object spectroscopy

TL;DR

This study analyzes six years of data on fibre-optic transmission in astronomy, showing stable bulk transmission but identifying end termination losses, with potential improvements through better maintenance.

Contribution

It provides long-term empirical data on fibre-optic stability in astronomical instruments and identifies specific sources of transmission loss.

Findings

No significant degradation in bulk transmission over six years

End termination losses account for most performance degradation

Maintenance can significantly improve fibre-optic performance

Abstract

We present an analysis of the long-term stability of fibre-optic transmission properties for fibre optics in astronomy. Data from six years of operation of the AAOmega multi-object spectrograph at the Anglo-Australian Telescope is presented. We find no evidence for significant degradation in the bulk transmission properties of the 38 m optical fibre train. Significant losses (<20% relative, 4% absolute) are identified and associated with the end termination of the optical fibres in the focal plane. Improved monitoring and maintenance can rectify the majority of this performance degradation.