ABSTRACT
Integrated photonics is increasing in importance for compact, robust, and scalable enabling quantum technologies. This is particularly interesting for developing quantum communication networks, where resources need to be deployed in the field. We exploit photonic chip-based Si3N4 microring resonators to realise a photon pair source with low-loss, high-noise suppression and coincidence rates of 80×103 s-1. A simple photonic noise characterisation technique is presented that distinguishes linear and nonlinear contributions useful for system design and optimisation. We then demonstrate an all-fiber 750 MHz clock-rate sequential Time-Bin entanglement scheme with raw interference visibilities > 98 %.
ABSTRACT
We present a quantum key distribution system with a 2.5 GHz repetition rate using a three-state time-bin protocol combined with a one-decoy approach. Taking advantage of superconducting single-photon detectors optimized for quantum key distribution and ultralow-loss fiber, we can distribute secret keys at a maximum distance of 421 km and obtain secret key rates of 6.5 bps over 405 km.
ABSTRACT
One of the main challenges for future quantum information technologies is the miniaturization and integration of high performance components in a single chip. In this context, electrically driven sources of nonclassical states of light have a clear advantage over optically driven ones. Here we demonstrate the first electrically driven semiconductor source of photon pairs working at room temperature and telecom wavelengths. The device is based on type-II intracavity spontaneous parametric down-conversion in an AlGaAs laser diode and generates pairs at 1.57 µm. Time-correlation measurements of the emitted pairs give an internal generation efficiency of 7×10(-11) pairs/injected electron. The capability of our platform to support the generation, manipulation, and detection of photons opens the way to the demonstration of massively parallel systems for complex quantum operations.
