Single-photon frequency upconversion for long-distance quantum teleportation and communication

Abstract

Entanglement generation, single-photon detection, and frequency translation that preserves the polarization quantum state of the photons are essential technologies for long distance quantum communication protocols. This thesis investigates the application of polarization entanglement to quantum communication, including frequency upconversion, photon-counting detection, and photon-pair and entanglement generation. We demonstrate a near-unity efficient frequency conversion scheme that allows fast and efficient photon counting at wavelengths in the low-loss fiber optic and atmospheric transmission band near 1.55 /im. This upconverter, which is polarization-selective, is useful for classical as well as quantum optical communication. We investigate several schemes that allow frequency translation of polarization-entangled photons generated via spontaneous parametric downconversion in second order non-linear crystals. We demonstrate upconversion from 1.56 to 0.633 m that preserves the polarization state of an arbitrarily polarized input. The polarization-insensitive upconverter uses bidirectional sum-frequency generation in bulk periodically poled lithium niobate and a Michelson interferometer to stabilize the phase. Using this bidirectional upconversion technique, entangled photons produced in a periodically poled parametric downconverter can be translated to a different wavelength with preservation of their polarization state. We discuss the implications of these results for quantum information processing.