  Many photonic quantum information processing applications would benefit from
a high brightness, fiber-coupled source of triggered single photons. Here, we
present a fiber-coupled photonic-crystal waveguide single-photon source relying
on evanescent coupling of the light field from a tapered out-coupler to an
optical fiber. A two-step approach is taken where the performance of the
tapered out-coupler is recorded first on an independent device containing an
on-chip reflector. Reflection measurements establish that the chip-to-fiber
coupling efficiency exceeds 80 %. The detailed characterization of a
high-efficiency photonic-crystal waveguide extended with a tapered out-coupling
section is then performed. The corresponding overall single-photon source
efficiency is 10.9 % $\pm$ 2.3 %, which quantifies the success probability to
prepare an exciton in the quantum dot, couple it out as a photon in the
waveguide, and subsequently transfer it to the fiber. The applied out-coupling
method is robust, stable over time, and broadband over several tens of
nanometers, which makes it a highly promising pathway to increase the
efficiency and reliability of planar chip-based single-photon sources.
