As currently implemented, single photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons.Because of this, single photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted independently, enabling a much better approximation of a source of single photons on demand.The scheme uses a heralded photon source based on parametric downconversion, but by effectively breaking the trigger detector area into multiple regions, we are able to extract extra information about a heralded photon than is possible with a conventional arrangement.This scheme allows photons to be produced along with a quantitative ``certification'' that they are single photons. Some of the single photon certifications can be significantly better than what is possible with conventional downconversion sources (using a unified trigger detector region), as well as being better than faint laser sources. With such a source of more tightly certified single photons, it should be possible to improve the maximum secure bit rate possible over a quantum cryptographic link. We present an analysis of the relative merits of this method over the conventional arrangement.
Proceedings Title: Free-Space Laser Communication and Laser Imaging, Conference | 2nd | Free-Space Laser Communication and Laser Imaging II | SPIE
Conference Dates: July 1, 2002
Conference Title: Proceedings of SPIE--the International Society for Optical Engineering
Pub Type: Conferences
on demand, photon, photon source, quantum communication, quantum cryptography, single photons