Sources of entangled photons

Climério Paulo da Silva Neto

Wang Qing-yue

Entangled photon sources are the basis of the quantum communication and quantum computation. To produce the high-flux, stable, effective source of EPR entangled photon is essential for realizing the quantum teleportation. The mechanisms and conventional techniques for fabricating the entangled photon sources are presented and the latest progresses of the experimental investigations of the entangled photon sources are described.

Goswami, Abhirup

Quantum repeaters are the most promising approach for distributing entanglement over long distances. Recent approaches to develop quantum repeaters involve the use of deterministic entangled photon pair sources. On the other hand heralded entangled photon pair sources have been proposed independently both with parametric down conversion source and single photon sources. We modify the latter scheme to implement it as an on demand entangled photon pair source and analyse its performance considering inefficient detectors, inefficient quantum memories and inefficient single photon sources. We conclude that with the current state of art, generation of high fidelity deterministic entangled photon pairs is possible with moderate efficiency. We then compare the results to the deterministic entangled photon pair source obtainable using parametric down conversion source and conclude that the single photon scheme described in this thesis is more practical for such an implementation.

Amaal M. Ali, Natasha Bastien, Wendy-Ann Gibbons +2 more

Andi Shahaj

Entangled photon sources have applications in such fields as quantum communications, quantum sensing and quantum computing. Of particular interest are pulsed entangled photon sources, as they provide an additional degree of freedom – the temporal degree of freedom – to manipulate entanglement properties, hence increasing the information capacity of the entangled photons they produce. An entangled photon source in the telecom wavelength typically requires a 780 nm pump laser. So far, in most cases, pulsed entangled photon sources are pumped by the Ti:Sapph mode-locked laser, which, due to its bulky size and high cost, has limited the widescale adoption of pulsed entangled photon sources. In this thesis, I demonstrate a simple, cost-effective, pulsed laser diode capable of competing with the Ti:Sapph for the purposes of entangled photon generation. The diode and driver are capable of pulsing at up to 60 MHz , with peak power exceeding 1 W and pulse energy in excess of 1 nJ , and with a spectral width narrower than 0.1 nm. I also demonstrate a pulsed, fully fiber-based, entangled photon source, with high entanglement quality (maximum concurrence of 0.985) and a high pair generation rate (0.15 pairs/pulse). The source is to our knowledge the first of its kind.

Krishna Thyagarajan