Fast Quantum Entanglement



Project Abstract

Entanglement is a very versatile quantum resource for many quantum applications ranging from communication to quantum computing. In quantum communication it is indispensable for the implementation of quantum repeaters that will allow the creation of the future quantum internet. But even now, entanglement is already employed for quantum key distribution (QKD) and optical quantum computers. Wider take up of entangled photon sources for these tasks is hampered by their low generation rate (MHz) as compared to GHz generation of weak coherent pulses in QKD set-ups.

The FAQT project is specifically designed to demonstrate a high generation rate of entangled photons using off-the-shelf components. The high rate will make entanglement sources more attractive to be employed for quantum communication applications and will also increase the clock speed of all-optical quantum computers, allowing a greater depth of quantum algorithms to be run. The aim to produce a compact and robust set-up with standard parts will facilitate the quick take up and deployment of the technological developments in upcoming quantum communication initiatives.

To increase the production rate, the FAQT project will devise a new pump laser set-up, capable of producing a repetition rate of up to 42 GHz. This will swarth earlier demonstrations which were in the range of 1 to 10 GHz. The high repetition rate means that the pump power per pulse can be reduced sufficiently to suppress multi-pair emission and hence produce very high fidelity of entangled states even at such high rates.

To achieve this, a pump laser set-up will be assembled containing not only the pulsed laser source but also opto-electronic pulse picking to control and adjust the repetition rate (1 – 42 GHz), an optical amplification stage to boost pump power to drive the generation process and finally a frequency conversion stage to yield the correct pump frequency. The quantum optical set-up will be optimized to increase generation efficiency so that entangled photons pairs are generated with rates above 1 GHz. Superconducting single photon detectors will be employed to achieve also an unprecedented detection rate (50 MHz) of high-fidelity entanglement. The whole set-up will be made from commercially available components to facilitate a quick development of a deployment-ready source of photonic entanglement.