Publication details
Robustness of light-transport processes to bending deformations of graded-index multimode waveguides
Authors | |
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Year of publication | 2018 |
Type | Article in Periodical |
Magazine / Source | Physical Review Letters |
MU Faculty or unit | |
Citation | |
Web | https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.233901 |
Doi | http://dx.doi.org/10.1103/PhysRevLett.120.233901 |
Keywords | Gradient-index optical fiber; bending; eigenmodes |
Description | 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. |
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