Efficient photon triplet generation in integrated nanophotonic waveguides

• Published in: Optics express Vol. 24; no. 9; pp. 9932 - 9954
• Main Authors: Moebius, Michael G., Herrera, Felipe, Griesse-Nascimento, Sarah, Reshef, Orad, Evans, Christopher C., Guerreschi, Gian Giacomo, Aspuru-Guzik, Alán, Mazur, Eric
• Format: Journal Article
• Language: English
• Published: United States 02.05.2016
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.24.009932

Generation of entangled photons in nonlinear media constitutes a basic building block of modern photonic quantum technology. Current optical materials are severely limited in their ability to produce three or more entangled photons in a single event due to weak nonlinearities and challenges achieving phase-matching. We use integrated nanophotonics to enhance nonlinear interactions and develop protocols to design multimode waveguides that enable sustained phase-matching for third-order spontaneous parametric down-conversion (TOSPDC). We predict a generation efficiency of 0.13 triplets/s/mW of pump power in TiO -based integrated waveguides, an order of magnitude higher than previous theoretical and experimental demonstrations. We experimentally verify our device design methods in TiO waveguides using third-harmonic generation (THG), the reverse process of TOSPDC that is subject to the same phase-matching constraints. We finally discuss the effect of finite detector bandwidth and photon losses on the energy-time coherence properties of the expected TOSPDC source.