Observing nonlinear optical quantum effects or implementing quantum information protocols using nonlinear optics requires moving to ever-smaller input light intensities. However, low light intensities generally mean weak optical nonlinearities, inadequate for many applications. Here we calculate the performance of four-wave mixing in various optical fibers for the case where one of the input beams is a single photon. We show that in tapered chalcogenide glass fibers (microwires) a single photon plus strong pump beam can produce a pair of photons with probability 0.1%, much higher than in previous work on bulk and waveguided crystal sources. Such a photon converter could be useful for creating large entangled photon states, for performing a loophole-free test of Bell's inequalities, and for quantum communication.
@article{arxiv.1407.1250,
title = {Converting one photon into two via four-wave mixing in optical fibers},
author = {Audrey Dot and Evan Meyer-Scott and Raja Ahmad and Martin Rochette and Thomas Jennewein},
journal= {arXiv preprint arXiv:1407.1250},
year = {2014}
}