Abstract: | We propose an arbitrary controlled-unitary(CU) gate and a bidirectional quantum teleportation(BQTP) scheme. The proposed CU gate utilizes photonic qubits(photons) with cross-Kerr nonlinearities(XKNLs), X-homodyne detectors, and linear optical elements, and consists of the consecutive operation of a controlled-path(C-path) gate and a gathering-path(Gpath) gate. It is almost deterministic and feasible with current technology when a strong coherent state and weak XKNLs are employed. Based on the CU gate, we present a BQTP scheme that simultaneously teleports two unknown photons between distant users by transmitting only one photon in a path-polarization intra-particle hybrid entangled state. Consequently, it is possible to experimentally implement BQTP with a certain success probability using the proposed CU gate. |