Attenuation Coefficient of Single-Mode Periodic Waveguides

Alexandre Baron (1) , Simon Mazoyer (1) , Wojciech Śmigaj (1) , Philippe Lalanne (2, 1)

1 Laboratoire Charles Fabry de l'Institut d'Optique / Naphel
2 lp2n-03,lp2n-13

It is widely accepted that, on ensemble average, the transmission T of guided modes decays exponentially with the waveguide length L due to small imperfections, leading to the important figure of merit defined as the attenuation-rate coefficient α=-⟨ln⁡(T)⟩/L. In this Letter, we evidence that the exponential-damping law is not valid in general for periodic monomode waveguides, especially as the group velocity decreases. This result, that contradicts common beliefs and experimental practices aiming at measuring α, is supported by a theoretical study of light transport in the limit of very small imperfections, and by numerical results obtained for two waveguide geometries that offer contrasted damping behaviors.

Domaines: Optique [physics.optics]; Electromagnétisme; Micro et nanotechnologies/Microélectronique; Optique / photonique

Alexandre Baron, Simon Mazoyer, Wojciech Śmigaj, Philippe Lalanne. Attenuation Coefficient of Single-Mode Periodic Waveguides. Physical Review Letters, 2011, 107 (15), pp.153901. ⟨10.1103/PhysRevLett.107.153901⟩. ⟨hal-00675334⟩