Simple circuit of linear optics logic gates

Abstract

We review an experimental demonstration of a simple irreversible circuit of two probabilistic exclusive-OR (XOR) gates for single-photon qubits. We describe the operation of the individual linear-optics gates and the overall circuit in terms of two-photon and three-photon quantum interference effects. We also discuss future plans for quantum circuits using single-photon qubits from stored parametric down-conversion sources.

High-performance guided-wave asynchronous heralded single-photon source

“…Thus the preparation efficiency Γ, which can be seen as the "guide-to-single mode fiber" coupling efficiency, was found to be 0.59. As previous experiments based on bulk crystals showed photon collection efficiencies ranging from 0.03 to 0.83 [12][13][14], our waveguiding structure does not improve the best results. However, it is important to note here that only one butt-coupled fiber is necessary to obtain high collection efficiency thanks to the collinear PPLN guiding structure thus offering better stability and ease to use.…”