We describe the design and application of domain-engineered, periodically poled lithium niobate (PPLN) for use to produce entangled photons and for other tools in quantum information and communications. By specially designing and controlling the PPLN poling pattern, multiple nonlinear optical processes can be simultaneously phasematched. This capability can be used to generate polarization-entangled photon pairs through type-II spontaneous parametric downconversion. The single PPLN crystal is designed to produce both the |HV〉 and |VH〉 states where the downconverted photons are distinguishable by wavelengths, which enables generation of post-selection-free, polarization-entangled twin photons. We describe the design and fabrication of the PPLN crystal, and initial experimental results for downconversion of a 775 nm pump to 1532 nm and 1567 nm orthogonally polarized photons. We also discuss other applications of engineered optical frequency conversion for quantum information including the use of dual-wavelength upconversion as a beamsplitter to route or analyze photons.

Date Published: 1 May 2014
PDF: 8 pages
Proc. SPIE 9136, Nonlinear Optics and Its Applications VIII; and Quantum Optics III, 913603 (1 May 2014); doi: 10.1117/12.2058567

Published in SPIE Proceedings Vol. 9136:
Nonlinear Optics and Its Applications VIII; and Quantum Optics III
Benjamin J. Eggleton; Alexander V. Sergienko; Arno Rauschenbeutel; Alexander L. Gaeta; Neil G. R. Broderick; Thomas Durt, Editor(s)