  Coupling individual quantum systems lies at the heart of building scalable
quantum networks. Here, we report the first direct photonic coupling between a
semiconductor quantum dot and a trapped ion and we demonstrate that single
photons generated by a quantum dot controllably change the internal state of an
$\textrm{Yb}^+$ ion. We ameliorate the effect of the sixty-fold mismatch of the
radiative linewidths with coherent photon generation and a high-finesse
fiber-based optical cavity enhancing the coupling between the single photon and
the ion. The transfer of information presented here via the classical
correlations between the $\sigma_z$-projection of the quantum-dot spin and the
internal state of the ion provides a promising step towards quantum
state-transfer in a hybrid photonic network.
