Hong-Ou-Mandel cloning: Quantum copying without an ancilla
Irfan Ali Khan, John C. Howell · Physical Review A · 2004
In this paper we report an experimental realization of an ancilla-free $1\ensuremath{\rightarrow}2$ phase-covariant quantum cloner. The cloner is realized by interfering a linearly polarized photon, which we wish to clone with a circularly polarized photon at a beam splitter. The two-photon effect can be understood in light of Hong-Ou-Mandel interference. The fidelity of the cloner was measured as $0.829\ifmmode\pm\else\textpm\fi{}0.008$ for the $0∕90$ basis and $0.835\ifmmode\pm\else\textpm\fi{}0.006$ for the $45∕135$ basis, which is in good agreement with the theoretical prediction of $5∕6$ fidelity. The experimental scheme is straightforward and has a high cloning success rate.