Efficient quantum dot single photon extraction into an optical fiber   using a nanophotonic directional coupler
  We demonstrate a spectrally broadband and effcient technique for collecting photoluminescence from a single InAs quantum dot directly into a standard single mode optical fiber. In this approach, an optical fiber taper waveguide is placed in contact with a suspended GaAs nanophotonic waveguide with embedded quantum dots, forming an effcient and broadband directional coupler with standard optical fiber input and output. Effcient photoluminescence collection over a wavelength range of tens of nanometers is demonstrated, and a maximum collection effciency of 6.05 % (corresponding single photon rate of 3.0 MHz) into a single mode optical fiber was estimated for a single quantum dot exciton. 
M. Davanco, M.T. Rakher, W. Wegscheider, D. Schuh, A. Badolato and K.   Srinivasan
physics.optics quant-ph