Experimental demonstration of polarization-based decoy-state BB84 quantum key distribution utilizing a single laser and single detector

As quantum key distribution progresses into commercial products and services, there is growing interest in technological solutions that improve performance and/or reduce costs. We present an experimental demonstration of polarization-based decoy-state BB84 quantum key distribution protocol, at a clock frequency of 50 MHz, that relies on fewer resources at the receiver and increases robustness to side-channel attacks for both transmitter and receiver. A single-laser source and cascade of electro-optic modulators provide the four polarization states, while a photonic recombiner with time-multiplexed inputs enables detection with a single single-photon detector.