title: Coupling light into a slow-light photonic-crystal waveguide from a free-space normally-incident beam.
abstract: We present a coupler design allowing normally-incident light coupling from free-space into a monomode photonic crystal waveguide operating in the slow-light regime. Numerical three-dimensional calculations show that extraction efficiencies as high as 80% can be achieved for very large group indices up to 100. We demonstrate experimentally the device feasibility by coupling and extracting light from a photonic crystal waveguide over a large group-index range (from 10 to 60). The measurements are in good agreement with theoretical predictions. We also study numerically the impact of various geometrical parameters on the coupler performances.
authors.affiliation: Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, 91460 Marcoussis, France. philippe.hamel@lpn.cnrs.fr
authors.forename: P
authors.initials: P
authors.lastname: Hamel
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authors.lastname: Grinberg
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authors.lastname: Sauvan
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authors.lastname: Lalanne
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authors.lastname: Baron
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authors.lastname: Yacomotti
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authors.lastname: Sagnes
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authors.lastname: Raineri
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authors.lastname: Bencheikh
authors.forename: J A
authors.initials: JA
authors.lastname: Levenson