  In this work we demonstrate a triggered single-photon source operating at the
telecom C-band with photon extraction efficiency exceeding any reported values
in this range. The non-classical light emission with low probability of the
multiphoton events is realized with single InAs quantum dots (QDs) grown by
molecular beam epitaxy and embedded directly in an InP matrix. Low QD spatial
density on the order of 5x108 cm-2 to ~2x109 cm-2 and symmetric shape of these
nanostructures together with spectral range of emission makes them relevant for
quantum communication applications. The engineering of extraction efficiency is
realized by combining a bottom distributed Bragg reflector consisting of 25
pairs of InP/In0.53Ga0.37Al0.1As layers and cylindrical photonic confinement
structures. Realization of such technologically non-demanding approach even in
a non-deterministic fashion results in photon extraction efficiency of
(13.3+/-2)% into 0.4 numerical aperture detection optics at approx. 1560 nm
emission wavelength, i.e., close to the center of the telecom C-band.
