Active teleportation of a quantum bit

We report the experimental realization of the ``active'' quantum teleportation (QST) of a one-particle entangled qubit. This demonstration completes the original QST protocol and renders it available for actual implementation in quantum computation networks. It is accomplished by implementing an 8 m optical delay line and a single-photon triggered fast electro-optic Pockels cell. A large value of teleportation ``fidelity'' was attained: Fₐ=(90∓2)%. Our work follows the line recently suggested by H. W. Lee and J. Kim [Phys. Rev. A $63,$ 012305 (2000)] and E. Knill, R. Laflamme, and G. Milburn [Nature (London) $409,$ 46 (2001)].