Optical fiber coupling to planar photonic crystal microcavities
  A technique is demonstrated which efficiently transfers light between a tapered standard single-mode optical fiber and a resonant mode of a high-Q photonic crystal cavity with mode volume less than a cubic wavelength in size. Cavity mode quality factors of 4.7 x 10^4 are measured, and a total fiber-to-cavity coupling efficiency of 44% is demonstrated. 
Paul E. Barclay, Kartik Srinivasan, Oskar Painter