Quantum computing offers a promising pathway to solving problems that are intractable for classical computers. Despite impressive progress, the development of a scalable quantum information processor remains an open challenge. Several hardware platforms remain contenders, with photonic systems being a strong candidate. Until recently, state-of-the-art photonic quantum processors have used path encoding, which often requires an exponentially increasing number of optical components, making these schemes unavoidably large or lossy in some cases. Time-bin encoding has emerged as a promising method to reduce the number of optical components in a photonic quantum processor by enabling operation along a single optical path. Yet, a barrier to the widespread adoption of time-bin encoding is the challenge of maintaining phase stability across the entire device for extended periods of time. We overcome this obstacle here through ultrafast time-bin encoding, in which time bins are separated by just a few picoseconds. This talk will present our ability to generate, manipulate, and measure these ultrafast time bins at the single-photon level, demonstrating the promise of our platform across a wide range of applications.