Endlessly adiabatic fiber with a logarithmic refractive index distribution

Kerrianne Harrington, S. Yerolatsitis, Dennis van Ras, Dionne M. Haynes, T. A. Birks

Research output: Contribution to journalArticlepeer-review

18 Citations (SciVal)


It is well known that a fiber taper—an optical fiber whose size varies along its length—must exceed a certain minimum length to be adiabatic and low-loss. In contrast, we show that an optical fiber with a logarithmic refractive index profile can be adiabatically tapered over any length, however short. Its mode field distribution is independent of the fiber’s size and so remains the same along a taper. We report an experimental fiber in which tapers shorter than 2 mm can have losses as low as 0.03 dB. The fiber is compatible with standard telecoms fiber but with low bend loss and should have applications where it is desirable to make tapered fiber components (such as fused couplers and photonic lanterns) as short as possible. The index profile is analogous to the logarithmic potential of quantum mechanics.

Original languageEnglish
Pages (from-to)1526-1533
Number of pages8
Issue number12
Early online date15 Dec 2017
Publication statusPublished - 20 Dec 2017


  • Fiber design and fabrication
  • Fiber optics components

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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