By employing the transverse spatial degree-of-freedom of a single photon we demonstrate a quantum random number generator based on high-dimensional qutrits on few-mode fibers towards future implementations of measurement device-independent protocols for improved security.

Dynamic storage of qubits is crucial for quantum communication networks. Here we present an adjustable buffer capable of storing photonic polarization quantum states in a fiber loop controllable by a poled fiber modulator.

We demonstrate interference of weak coherent states with a visibility of up to 91.8% in a Sagnac interferometer over 219.4 km of deployed fiber, pointing to practical deployment of multi-user twin-field quantum key distribution.