Polarization Rotation in Ring Resonators

  • Francesco MorichettiEmail author
Part of the Springer Series in Optical Sciences book series (SSOS, volume 156)


Densely integrated photonic devices require high-index contrast waveguides supporting small bending radii with negligible loss. However, when optical waveguides are tightly curved, polarization rotation (PR) effects can arise. In this chapter, PR in bent waveguides is theoretically and numerically investigated and its dependence on the main waveguide parameters is derived. It is shown that the efficiency of PR linearly increases with the refractive index contrast, is strongly inhibited by birefringence, and vanishes in the case of waveguides with a refractive index profile symmetrical in the direction orthogonal to the plane of the bend. In resonant structures PR is strongly enhanced and can severely distort the frequency response of ring resonators (RRs). Cavity-enhanced PR in RRs is discussed, and design rules to mitigate or enhance PR are provided. The detrimental effects due to undesired PR on the behavior of common architectures including RRs are shown. Examples of devices exploiting cavity-enhanced polarization rotation to implement highly efficient polarization rotators are presented.


Directional Coupler Mode Mode Waveguide Mode Transverse Electric Polarization Rotation 
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Copyright information

© Springer-Verlag US 2010

Authors and Affiliations

  1. 1.POLICOM - Dipartimento di Elettronica e InformazionePolitecnico di MilanoMilanoItaly
  2. 2.Fondazione Politecnico di MilanoMilanoItaly

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