To achieve complete security of communication, there is a need for “real-time” ultrafast physical random bit generators (RBGs). In the available physical RBGs, random bit extraction is effected in the electrical domain and, therefore, cannot directly function beyond the frequencies of 10 GHz or so in real time. Here, we present a fully photonic strategy for real-time random number generation and report a proof-of-concept experimental demonstration of an integrated 10 Gb/s RBG system (prototype) based on laser chaos. The use of an ultrastable mode-locked laser, together with ultrafast optical interactions, gives our method the capability to develop super-high-speed RBGs in practice. The photonic implementation is fully compatible with optical communications so that well-established optical multiplexing techniques can be used to realize Tb/s real-time random bit generation.