Abstract
We measured the transmission of tapered and untapered optical fibres as a function of input beam numerical aperture at 635 nm. The tapered fibres were fabricated with an adiabatic tapering process from graded and step-index fibres with 50 μm core diameters to form a 100 mm long taper with 5:1 taper ratio. We tested tapered graded-index and step-index fibres fabricated from commercial Thorlabs products and a custom graded-index taper. The 5:1 tapered graded-index fibre can give a transmission greater than 0.4 for Thorlabs and 0.6 for the custom taper. We simulated the transmission of the tapered fibres and found reasonable agreement with the measured graded-index tapered fibre results across the numerical aperture range of interest. Experimentally, step-index tapered fibres performed relative poorly and considerably below modelling expectations. Based on our examinations this arises because the properties of step-index fibre were not robust to the tapering process. Suitably tapered graded-index fibres may offer a new route for efficient focal ratio reduction of fibre optic signals, e.g., in fibre-fed spectrographs, though we stress that our measurements have been limited to monochromatic light in this work.
Original language | English |
---|---|
Article number | 102632 |
Journal | Optical Fiber Technology |
Volume | 66 |
Early online date | 24 Jul 2021 |
DOIs | |
Publication status | Published - 31 Oct 2021 |
Keywords
- Adiabatic tapered fibre
- COMSOL
- Fibre simulation
- Fibre transmission
- Graded-index fibre
- Numerical aperture characterisation
- Step-index fibre
- Zemax
ASJC Scopus subject areas
- Control and Systems Engineering
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Instrumentation
- Electrical and Electronic Engineering