Robustness of Light-Transport Processes to Bending Deformations in Graded-Index Multimode Waveguides

Dirk E. Boonzajer Flaes, Jan Stopka, Sergey Turtaev, Johannes F. De Boer, Tomáš Tyc, Tomáš ČiŽmár

Research output: Contribution to JournalArticleAcademicpeer-review


Light transport through a multimode optical waveguide undergoes changes when subjected to bending deformations. We show that optical waveguides with a perfectly parabolic refractive index profile are almost immune to bending, conserving the structure of propagation-invariant modes. Moreover, we show that changes to the transmission matrix of parabolic-index fibers due to bending can be expressed with only two free parameters, regardless of how complex a particular deformation is. We provide detailed analysis of experimentally measured transmission matrices of a commercially available graded-index fiber as well as a gradient-index rod lens featuring a very faithful parabolic refractive index profile. Although parabolic-index fibers with a sufficiently precise refractive index profile are not within our reach, we show that imaging performance with standard commercially available graded-index fibers is significantly less influenced by bending deformations than step-index types under the same conditions. Our work thus predicts that the availability of ultraprecise parabolic-index fibers will make endoscopic applications with flexible probes feasible and free from extremely elaborate computational challenges.

Original languageEnglish
Article number233901
Pages (from-to)1-5
Number of pages5
JournalPhysical Review Letters
Issue number23
Publication statusPublished - 6 Jun 2018


D. E. B. F. and J. F. de B. acknowledge support from the Netherlands Organisation for Scientific Research (NWO) with a Vici (JFdB) Grant No. 918.10.628. S. T. acknowledges funding from the EU FP7 People Programme (Marie Curie Actions) under REA Grant Agreement No. 608144. T. T. acknowledges support of Grant No. P201/12/G028 from the Czech Science Foundation. T. T. and T. Č. acknowledge support from the European Regional Development Fund through Project No. CZ.02.1.01/0.0/0.0/15_003/0000476. T. Č. acknowledges European Research Council (ERC), Grant No. 724530, the University of Dundee, and Scottish Universities Physics Alliance (PaLS initiative) for financial support.

FundersFunder number
University of Dundee
Horizon 2020 Framework Programme724530
Marie Curie
Scottish Universities Physics Alliance
European Research Council
Research Executive Agency608144, P201/12/G028
Grantová Agentura České Republiky
Nederlandse Organisatie voor Wetenschappelijk Onderzoek918.10.628
Seventh Framework Programme
European Regional Development FundCZ.02.1.01/0.0/0.0/15_003/0000476


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