title: Fiber-optics implementation of an asymmetric phase-covariant quantum cloner.
abstract: We present the experimental realization of optimal symmetric and asymmetric phase-covariant 1-->2 cloning of qubit states using fiber optics. The state of each qubit is encoded into a single photon which can propagate through two optical fibers. The operation of our device is based on one- and two-photon interference. We have demonstrated the creation of two copies for a wide range of qubit states from the equator of the Bloch sphere. The measured fidelities of both copies are close to the theoretical values and they surpass the theoretical maximum obtainable with the universal cloner.
authors.affiliation: Department of Optics, Palacký University, 17. listopadu 50, 772 00 Olomouc, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Bartůsková
authors.forename: Miloslav
authors.initials: M
authors.lastname: Dusek
authors.forename: Antonín
authors.initials: A
authors.lastname: Cernoch
authors.forename: Jan
authors.initials: J
authors.lastname: Soubusta
authors.forename: Jaromír
authors.initials: J
authors.lastname: Fiurásek