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 |
Bibliographical note
Funding Information:PC is supported by a Thai Government PhD scholarship. Support for WM, HRAJ, RE and the experimental setup is from the STFC Newton Fund ST/R006598/1, ST/P005667/1 and ST/T007311/1. SY is funded by the Opticon EPSRC Proteus project EP/R005257/1.
Funding Information:
This research has been assisted by very useful discussions with Prof. Tim A. Birks of the University of Bath. The Zemax simulation of tapered fibre was assisted by suggestions from Weerapot Wanajareon of Chiang Mai University. This work has made use of the University of Hertfordshire's high-performance computing facility and licensed software Maxlm DL6, COMSOL and Zemax. The authors are very grateful for the patience and constructive comments from the anonymous reviewers in the several revisions of the manuscript. The paper has been considerably improved by their suggestions.
Funding
PC is supported by a Thai Government PhD scholarship. Support for WM, HRAJ, RE and the experimental setup is from the STFC Newton Fund ST/R006598/1, ST/P005667/1 and ST/T007311/1. SY is funded by the Opticon EPSRC Proteus project EP/R005257/1. This research has been assisted by very useful discussions with Prof. Tim A. Birks of the University of Bath. The Zemax simulation of tapered fibre was assisted by suggestions from Weerapot Wanajareon of Chiang Mai University. This work has made use of the University of Hertfordshire's high-performance computing facility and licensed software Maxlm DL6, COMSOL and Zemax. The authors are very grateful for the patience and constructive comments from the anonymous reviewers in the several revisions of the manuscript. The paper has been considerably improved by their suggestions.
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