Loss engineered slow light waveguides

Liam O'Faolain, Sebastian Andreas Schulz, Daryl Matthew Beggs, Tom P White, M. Spasenovic, L. Kuipers, F. Morichetti, A. Melloni, S. Mazoyer, J. P. Hugonin, P. Lalanne, Thomas Fraser Krauss

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164 Citations (Scopus)
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Slow light devices such as photonic crystal waveguides (PhCW) and coupled resonator optical waveguides (CROW) have much promise for optical signal processing applications and a number of successful demonstrations underpinning this promise have already been made. Most of these applications are limited by propagation losses, especially for higher group indices. These losses are caused by technological imperfections ("extrinsic loss") that cause scattering of light from the waveguide mode. The relationship between this loss and the group velocity is complex and until now has not been fully understood. Here, we present a comprehensive explanation of the extrinsic loss mechanisms in PhC waveguides and address some misconceptions surrounding loss and slow light that have arisen in recent years. We develop a theoretical model that accurately describes the loss spectra of PhC waveguides. One of the key insights of the model is that the entire hole contributes coherently to the scattering process, in contrast to previous models that added up the scattering from short sections incoherently. As a result, we have already realised waveguides with significantly lower losses than comparable photonic crystal waveguides as well as achieving propagation losses, in units of loss per unit time (dB/ns) that are even lower than those of state-of-the-art coupled resonator optical waveguides based on silicon photonic wires. The model will enable more advanced designs with further loss reduction within existing technological constraints. (C) 2010 Optical Society of America

Original languageEnglish
Pages (from-to)27627-27638
Number of pages12
JournalOptics Express
Issue number26
Publication statusPublished - 20 Dec 2010


  • Photonic crystals
  • Pulse-compression
  • Silicon
  • Ultracompact
  • Enhancement
  • Conversion
  • Bandwidth


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