The first quantum network, dubbed Phio, is from Quantum Xchange whose business model is to provide secure quantum communication as a service. Their first phase which is under pilot test now is suited for financial firms that want to connect their offices on Wall Street in New York City with their back office operations in New Jersey, a distance of perhaps 20 miles. The company anticipates increasing this East Coast network in the future to extend from Boston to Washington, D.C. and later on developing a West Coast network that could extend from San Francisco to Los Angeles.
Quantum Xchange is partnering with communications infrastructure Zayo Group to use dark fiber that they have available, ID Quantique for quantum key distribution (QKD) hardware and the research institute Battelle for the trusted node hardware. Dark fiber is fiber optic cable that was installed originally for use with classical fiber optic communication but had not been put to use because the additional bandwidth had not yet been needed. Since photonic signals become weak over long distances, a trusted node acts as a secured repeater to regenerate the signal for use with longer distances. Since the maximum range for a quantum signal over a fiber optic cable is approximately 60 miles, Quantum Xchange will not need to use a trusted node in this initial implementation from New York to New Jersey, but they will need to use them for the longer distances in the subsequent phases. More information is available from Quantum Xchange’s press releases here and here.
The second announcement includes the plan to develop a quantum network between the DOE’s Argonne National Laboratory and Fermi National Acceleratory Laboratory which are located about 30 miles apart in the Chicago area. Because of the short distance, this network will also not require the use of a trusted node and it will also make use of dark optical communication fiber that was originally installed a dozen years ago to facilitate high speed, classical data communications between the two laboratories. More details on the plans for this network can be found here.
The two quantum networks are, however, not the first one to be installed in the U.S. The first one was announced by Battelle in October 2013 to establish a connection between their headquarters in Columbus, Ohio and a satellite office in Dublin, Ohio, a distance of about 20 miles. The largest fiber optic based quantum network that currently exists is one in China that runs from Beijing to Shanghai via Jinan and Heifei, a distance of about 2000 km (about 1200 miles) which does require the use of trusted nodes.