The Asgard/BIFROST pre-injection optics and fibre injection module: optomechanical design & lab results

Abstract

The BIFROST instrument is poised to revolutionize high-spectral resolution interferometry at the VLTI by extending the accessible wavelength range down to 1.0 µm, encompassing the Y, J, and H bands. In this paper, we discuss the optical design for BIFROST's pre-injection optics which correct for birefringence effects and longitudinal dispersion between the different beam lines. We present the optomechanical design for the light injection module that compresses the beams and injects them into single-mode fibres, while maintaining the full field-of-view of the VLTI auxiliary or unit telescopes. Our fibre switching module will allow for the injection of light into photonic devices optimised for different wavebands or applications. Finally, we outline our integration & alignment strategy and present the first characterisation results obtained in the optics lab at the University of Exeter. Show more