The development of QKD networks as a possible answer to the threat to encrypted communication posed by quantum computers has given rise to a variety of concepts and implementations in recent years. In terms of the scalability of such systems, photonic integrated circuits (PIC, photonic chips) are a promising approach. This not only makes the systems much more miniaturized and robust, but also more attractive for industrial production. Here, we present the concept and characterization of a photonic chip that can act as a source in an entanglement-based QKD network employing spontaneous four-wave mixing (SFWM) in microring resonators. In addition to photon-pair production, the chip also directly performs essential filtering tasks. Moreover, the photon-pair rate can be maintained constant over an extended period using a Pound-Drever-Hall-Locking method.