Quantum Network Testbed and Technology Development: FY18 Quantum System Sciences Technical Investment Program
Massachuetts Institute of Technology Lexington United States
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The quantum network testbed and technology development program, part of the Quantum Systems Science line program, seeks to build the technological components required for quantum networking and to integrate them into a deployed-fiber testbed. The multi-year outline of our program is a phased development approach that allows us to demonstrate important quantum networking capabilities in the near term while still developing infrastructure to build toward far-term applications. The first and simplest phase is direct transmission producing entangled pairs at one node and transmitting one photon to the other node, so the two nodes share entanglement. This phase was demonstrated in FY17. The next phase, multi-span networking with synchronization, was a significant part of our FY18 program. We built two new entangled-photon-pair sources designed to produce the high-visibility quantum interference required formulti-span networking, and we built a system to swap entanglement between them. So far, we have demonstrated a quantum interference visibility of 91 percent and single-source entanglement visibilities of 92 percent and above. We also developed two different synchronization schemes, the first of which is specifically intended to synchronize the repetition rates of remote entanglement sources. Preliminary measurements of this first scheme show excess timing jitter of 60 ps, and we expect to reduce this excess jitter in improved tests. The second scheme is a more general method for sharing time and frequency that offers greater functionality for example, this scheme could be used for synchronizing not only the repetition rates but also the phase between two clocks. Additionally, we packaged new integrated photonic devices and used an integrated photonic system as an optical switch to reduce packet loss and latency in a classical communication network via optical flow switching.
- Quantum Theory and Relativity