Efficient slow-light coupling in a photonic crystal waveguide without transition region.

We consider the coupling into a slow mode that appears near an inflection point in the band structure of a photonic crystal waveguide. Remarkably, the coupling into this slow mode, which has a group index ng>1000, can be essentially perfect without any transition region. We show that this efficient coupling occurs thanks to an evanescent mode in the slow medium, which has appreciable amplitude and helps satisfy the boundary conditions but does not transport any energy.

[1]  C M de Sterke,et al.  Efficient slow light coupling into photonic crystals. , 2007, Optics express.

[2]  Frozen light in periodic stacks of anisotropic layers. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.

[3]  T. Happ,et al.  Photonic crystal tapers for ultracompact mode conversion. , 2001, Optics letters.

[4]  D. Marcuse.  Theory of dielectric optical waveguides , 1974 .

[5]  J. Taylor.  Theory of Dielectric Optical Waveguides. 2nd Edition , 1992 .

[6]  H. Hamann,et al.  Active control of slow light on a chip with photonic crystal waveguides , 2005, Nature.

[7]  P Lalanne,et al.  Coupling into slow-mode photonic crystal waveguides. , 2007, Optics letters.

[8]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[9]  P Lalanne,et al.  Compact and efficient injection of light into band-edge slow-modes. , 2007, Optics express.

[10]  R. McPhedran,et al.  Bloch mode scattering matrix methods for modeling extended photonic crystal structures. I. Theory. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.