Fiber nonlinearity based entangled-photon sources

Entangled photons have special properties arising from their quantum nature and have been used for scientific purposes such as demonstrating quantum teleportation. Several fascinating applications for entangled photons have been proposed including quantum metrology, computation, communication, and key generation. However, generating entangled light is currently an experiment in itself, thereby hampering development of these promising applications. Most entangled light generation schemes use nonlinear crystals. Recently researchers associated with NuCrypt and Northwestern University have pioneered entangled photon sources that exploit the nonlinearity inherent in standard optical fiber. This is beneficial in many regards including excellent modal purity and easy low-loss fiber interconnects for entangled light. In Phase-I of this STTR we developed designs for a flexible entangled photon source that will generate high quality entangled photons in the 1310nm spectral window allowing them to co-propagate with traditional 1550nm optical communication signals without deleterious cross-talk. In Phase-II we will build and, in collaboration with Northwestern, characterize such entanglement source designs. An easy-to-use, convenient, and high-performance entanglement source will greatly increase the rate of progress in realizing important applications of entangled light, including highly secure quantum key distribution, quantum imaging, quantum metrology, and linear optics based quantum computing.