Experimental investigation of the robustness of partially entangled qubits over 11 km

Abstract

We experimentally investigate time-bin qubits for distributed quantum communication. The robustness of maximal and nonmaximal time-bin entangled qubits (photons) over distances up to 11 km is shown. The entanglement is set by controllable parameters and in all cases is found to be robust, in that the qubits maintain their degree of entanglement after transmission along telecommunication fiber.