Compact, CMOS compatible on-chip photon sources have attracted much attention to the scientific community and the semiconductor industry. As the transistor's feature size is continuously scaling down, the integration density and switching speed in integrated electronic circuits increases exponentially. This leads to an increasingly large power dissipation from electrical connections between circuit elements. Optical (photonic) interconnects and their core element—the on-chip photon source—represent a promising alternative to circumvent this limitation. However, the most promising state-of-the-art on-chip photon sources typically feature a micrometer-scale size—1,000 times larger than transistors and prevent large-scale integration. Memristors, with active areas in the nanometer or even atomic scale, could be advantageously merged with optical functions to circumvent this limitation while providing versatile functionalities.