Nonlinear Optics for Photonic Quantum Networks

Abstract

By harnessing quantum mechanical effects we can create technology with greatly improved functionality including enhanced sensing, exponentially faster computing, the simulation of previously inaccessible quantum systems, and the secure transfer of information. In our ever more connected world, it is important that we can communicate securely, and as technology develops into the quantum regime it will become important for distant quantum processors to exchange information over a quantum network. Here we discuss how quantum information can be encoded and transferred around a such a network. We concentrate on the use of nonlinear optics to generate and manipulate photons, and present schemes for fully secure quantum communication.

Laser written circuits for quantum photonics

“…This approach is neither scalable nor efficient since overlapping multiple spatial modes on a crystal is challenging. In recent years, there has been substantial progress towards developing fully integrated single photon sources in a number of platforms, and using both quadratic and cubic nonlinearities (see for several reviews in this area).…”

Effect of dark counts on single-photon heralding with quasi-number-resolving detection schemes

“…To date, the most common method of producing single photons has been via probabilistic or "heralded" sources, in which a pair of photons is stochastically generated and one member of the pair detected to indicate the presence of the other [5]. These sources make use of the nonlinear optical processes of either spontaneous parametric downconversion, or spontaneous four-wave mixing, to probabilistically convert bright classical pump pulse photons into photon pairs.…”