Transmission properties of tapered optical fibres: Simulations and experimental measurements

Piyamas Choochalerm, William E. Martin, Hugh R.A. Jones, Ronny Errmann, Stephanos Yerolatsitis, Thomas A. Wright, Christophe Buisset

Research output: Contribution to journalArticlepeer-review

6 Citations (SciVal)


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 languageEnglish
Article number102632
JournalOptical Fiber Technology
Early online date24 Jul 2021
Publication statusPublished - 31 Oct 2021


  • Adiabatic tapered fibre
  • 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


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