Advanced Development for Defense Science and Technology: Measurement Tools for Quantum Information Processing

The special properties of quantum states make them attractive for emerging applications in quantum communication and computing. However, the very properties of quantum states that make them useful also make them difficult to measure. Quantum state tomography is a measurement tool which allows for complete characterization of quantum states. Although great progress has been made in researching quantum tomography techniques, there is a lack of available commercial equipment. Advances in the field of quantum information are severely hampered because every development group must build their own tools including even basic measurement devices. Moreover, current tomography demonstrations tend to be slow thereby providing little information about the quantum state drift over time. It is the goal of this Phase-II SBIR to develop a real-time photonic quantum state tomography system capable of high measurement speeds and having low background noise levels. The system will also be capable of generating fiber-coupled entangled photons on a standard wavelength grid allowing for multi-user quantum communication networks. The prototype will measure fiber-optic coupled quantum signals at high speeds (~10 Hz) and display the complex state information to the user in an intuitive way.