Spiral modes supported by circular dielectric tubes and tube segments

  • Lena Ebers
  • Manfred HammerEmail author
  • Jens Förstner


The modal properties of curved dielectric slab waveguides are investigated. We consider quasi-confined, attenuated modes that propagate at oblique angles with respect to the axis through the center of curvature. Our analytical model describes the transition from scalar 2-D TE/TM bend modes to lossless spiral waves at near-axis propagation angles, with a continuum of vectorial attenuated spiral modes in between. Modal solutions are characterized in terms of directional wavenumbers and attenuation constants. Examples for vectorial mode profiles illustrate the effects of oblique wave propagation along the curved slab segments. For the regime of lossless spiral waves, the relation with the guided modes of corresponding dielectric tubes is demonstrated.


Integrated optics Bent slab waveguides Oblique propagation Bend modes Tube modes Spiral waves Numerical/analytical modeling 



Financial support from the German Research Foundation (Deutsche Forschungsgemeinschaft DFG, Projects HA 7314/1-1, GRK 1464, and TRR 142) is gratefully acknowledged.


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© Springer Science+Business Media New York 2017

Authors and Affiliations

  1. 1.Theoretical Electrical EngineeringPaderborn UniversityPaderbornGermany

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