Semiconductor sources of photon pairs G. Weihs* 1,2 , T. Günthner 1 , B. Pressl 1 , R. Horn 2 , P. Abolghasem 3 , B. J. Bijlani 3 , D. Kang 3 , A. S. Helmy 3 1 Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria 2 Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, N2L 3G1, Canada 3 The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada ABSTRACT We demonstrate efficient photon pair generation for quantum communication using an all-semiconductor approach. In an AlGaAs Bragg-reflection waveguide we employ spontaneous parametric down-conversion to produce photon pairs at telecommunication wavelengths. The various phase-matching solutions present in our device can be used to create time- bin or polarization entanglement. This approach can to lead to a fully integrated photon pair source with the pump laser, active and passive optical devices all on a single semiconductor chip. Keywords: Bragg-reflection waveguides, parametric down-conversion, waveguide nonlinear optics, entanglement 1. INTRODUCTION Experiments with single photons and entangled photon pairs have arguably triggered a scientific revolution. Not only physicists but also computer scientists nowadays find themselves fascinated by the potential applications of quantum information processing, not in the least for a better understanding of the quantum world itself. But quantum mechanical entanglement and single photons have wider uses than even that. These non-classical states of light can be used to enhance measurements; they serve as radiometric standards and calibrate optical detectors. Quantum key distribution has already gone commercial and it appears that entanglement based implementations may lead to links that span the continents when deployed on satellites. Further development and physical understanding would strongly benefit from versatile and miniaturized non-classical light sources. This would pave the way towards the realization of complex optical quantum networks and integrated circuits on a single chip. Such a platform can indeed open new prospects for the fundamental investigation of quantum physics with single and entangled photons. One major drawback with the traditional photon pair sources based on spontaneous parametric down-conversion (SPDC) 1, 2 is that they are rather unwieldy and require significant amounts of resources for construction and operation. The best implementations using bulk crystals nowadays are based on interferometric optical set-ups and achieve very good quality of entanglement and brightness 3, 4 . Truly integrated sources of entanglement do not yet exist. Quantum-dot based entangled light-emitting-diodes (LEDs) 5 are the peak of the development but their performance is limited. Dielectric waveguides have been employed successfully 6 for about a decade and good entanglement and brightness are routinely achieved nowadays. Another, concurrent approach is the use of dispersion-shifted 7 or microstructured 8, 9 fibers resulting in all-fiber sources of entanglement. Both of these approaches can solve the problem of alignment, but neither is very successful in reducing the complexity and improving the functionality of the components. Quantum optics, optical quantum information processing as well as quantum communication would profit tremendously from miniaturized and integrated sources of single photons and entangled photon pairs because not only would they allow very compact traditional set-ups even with off-chip optical networks and detectors, but they may lead to an all- *gregor.weihs@uibk.ac.at; phone +43 512 507 52550; fax +43 512 507 53599 Invited Paper Advances in Photonics of Quantum Computing, Memory, and Communication VI, Zameer U. Hasan, Philip R. Hemmer, Hwang Lee, Charles M. Santori, Eds., Proc. of SPIE Vol. 8635, 863518 © 2013 SPIE · CCC code: 0277-786X/13/$18 · doi: 10.1117/12.2002591 Proc. of SPIE Vol. 8635 863518-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 12/05/2014 Terms of Use: http://spiedl.org/terms