The realization of strong light-matter interaction is crucial for many applications in quantum science and quantum technology. In particular, it allows one to link individual nodes of a large-scale quantum network or to mediate deterministic photon-photon interactions, which are required for many quantum protocols. Strong light-matter interaction has been successfully demonstrated in different systems, including optical resonators. However, for being applicable to photonic quantum information processing high photon losses of existing implementations hamper many applications. One way to avoid these losses is to employ whispering-gallery-mode resonators, which, despite their ultra-high quality and small volume, allow extremely efficiently coupling to waveguides. Furthermore, the strong transverse confinement of the light in these structures gives rise to extraordinary polarization properties which cause chiral, i.e. direction-dependent, coupling between light and matter. ^In this thesis, I report on the realization of two novel photonic devices which are based on the chiral interaction between light circulating in a bottle microresonator and a single rubidium atom. The first device is a nonlinear phase shifter, that realizes a strong optical nonlinearity on the single photon level. This nonlinearity is based on the nonlinear response of a single atom, which is enhanced by the resonator. By performing quantum state tomography of the field passing the atom-resonator system, we demonstrate the maximal nonlinear phase shift of 180 degrees between the case where single or pairs of photons pass the resonator. Furthermore, we verify that this process creates entanglement between two previously independent photons. The second device is a four-port quantum circulator, which is formed by two fiber couplers and the resonator. The chiral coupling between the atom and the resonator then gives rise to nonreciprocal transmission properties. ^We also show that the operation direction of the circulator is controlled by the spin state of the atom and can be inverted. This, in principle allows one to prepare a superposition of the two circulator operation directions. Furthermore, we study the nonlinear performance of the demonstrated circulator. Here we observe that the system routs single photons to different ports as pairs of photons. The results presented in this thesis are important steps toward realizing new, fully fiber-integrated components for quantum information processing.