Coupling light into a slow-light photonic-crystal waveguide from a free-space normally-incident beam

Philippe Hamel (1) , Patricio Grinberg (1) , Christophe Sauvan (2) , Philippe Lalanne (2) , Alexandre Baron (2) , Alejandro M. Yacomotti (1) , Isabelle Sagnes (1) , Fabrice Raineri (1) , Kamel Bencheikh (1) , Juan Ariel Levenson (1)

1 LPN - Laboratoire de photonique et de nanostructures
2 lp2n-03,lp2n-13

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.

Domaines: Optique / photonique; Optique [physics.optics]

Philippe Hamel, Patricio Grinberg, Christophe Sauvan, Philippe Lalanne, Alexandre Baron, et al.. Coupling light into a slow-light photonic-crystal waveguide from a free-space normally-incident beam. Optics Express, 2013, 21, pp.15144-15154. ⟨10.1364/OE.21.015144⟩. ⟨hal-00850462⟩