14:15 〜 14:30
▲ [25p-D214-6] Quantum interference between weak coherent light and SPDC photon pairs for three-photon time-bin entangled state generation
キーワード：time-bin entanglement, multi-photon entanglement, quantum interference with independent light sources
A photon is an important information carrier in quantum communication. As we know, polarization qubits have been widely used because they can be easily operated with optical components, but their quantum state is perturbed due to the polarization mode dispersion in long-distance optical fiber transmission. A time-bin state is a coherent superposition of two temporal modes and states. It had been used in many optical fiber-based quantum communication because of its robustness against polarization disturbance in optical fibers. Here, we proposed a scheme to generate three-photon time-bin entangled photon pairs with weak coherent light and spontaneous parametric down-conversion photon pairs. We launched independent light sources into a 2x2 optical switch, which was modulated as a partially time-dependent beam splitter. As a preliminary experiment, we performed quantum interference between the independent light sources by setting the optical switch as a half-beam splitter. The visibility of the Hong-Ou-Mandel interference was 78%.