Artist’s concept shows the TUNA architecture with an undersea fiber-optic backbone enabling a temporary communications network when traditional tactical data links are unavailable.
(Download Image)LLNL’s Optical Fibers Contribute to New Undersea Communications Technology
The Laboratory’s groundbreaking fiber optics program was featured in two high-level conferences with top Defense Department (DoD) officials earlier this year. Presentations at the conferences highlighted the Lab’s contributions to developing sophisticated underwater communications networks for national defense.
Scientists in the NIF & Photon Science Directorate have worked with the Defense Advanced Research Projects Agency (DARPA) and U.S. Navy laboratories on the Tactical Undersea Network Architectures, or TUNA, initiative. The program leverages unique, small-diameter, lightweight fiber optic cable to facilitate communications at sea.
Officials call TUNA "a novel, optical-fiber-based technology to temporarily restore radio frequency tactical data networks in a contested environment via an undersea optical fiber backbone."
NIF&PS Fiber Laser Group Leader Mike Messerly presented a summary of LLNL’s work on fiber optic cable work for TUNA at the conferences. The conferences were the National Defense Industrial Association (NDIA) 2017 Joint Undersea Warfare Technology Spring Conference and the 2017 Johns Hopkins University Applied Physics Laboratory (JHU/APL) Submarine Technology Symposium.
The TUNA program centers on the concept of deploying radio-networked buoys that would be linked undersea with neutrally-buoyant optical fibers—ultrathin hollow fibers that would neither float nor sink, but lie at a predetermined depth to avoid damage from fishing vessels and snagging on the ocean floor. The technology has captured much public interest, including articles in popular science magazines and a video DARPA posted highlighting completion of Phase 1 of the program:
The Fiber Laser Group’s challenge is to close the loop on the essential science involved in keeping the optics in a neutrally buoyant condition in a variety of ocean conditions and depths to maintain communications. In the event of a communications disruption, the TUNA buoys, each carrying communications equipment built to survive until communications can be restored, would be deployed at sea, then interconnected with optical fibers. The concept exploration phase of the TUNA program is complete and the program is now entering a demonstration phase, which includes at-sea testing.
"DARPA’s TUNA program has allowed us to expand and refine our fiber fabrication capabilities, and provided an opportunity to work with two Navy labs in California," said Messerly. He noted that the two conference presentations have been ideal venues for meeting officials who are planning future Navy applications and missions and discussing how LLNL’s fishing line-like neutrally buoyant fibers might fit into or support them.
The NDIA Joint Undersea Warfare Technology event, held April 24-26 in San Diego with senior Navy leadership, was hailed by conference organizers as "one of the few opportunities industry has to learn about what is working and what is not working in undersea warfare technology, what the Navy needs help with, and how and when industry may contribute to future initiatives."
Among the California sessions held was one on "Combat Systems/Warfighter Performance for DARPA’s TUNA Program, Enabling the Rapid Reconstitution of Tactical Data Networks in Contested Environments."
The second conference featuring LLNL fiber-optics participation was held in May at the Johns Hopkins Applied Physics Laboratory in Maryland.
One day during the three-day JHU/APL Submarine Technology Symposium focused on "Effects Ashore: Precision Navigation in a GPS Challenged/Denied Ashore Environment," and included a session on "Extremely thin neutrally buoyant optical fiber for multikilometer undersea communications."
The JHU/APL conference was capped by a roundtable discussion with Navy leadership, including Vice Adm. Joseph Tofalo, Commander of Navy Submarine Forces; Rear Adm. Fritz Roegge, Commander Submarine Force, U.S. Pacific Fleet; Rear Adm. Bill Merz, Director, Undersea Warfare Division (CNO-N97); Rear Adm. Moises DelToro III, Deputy Commander for Undersea Warfare, Naval Sea Systems Command; and George Drakeley III, Executive Director, Program Executive Officer, Submarines.
These conferences are an example of the NIF&PS fiber optics program continuing its expansion, enabled by the addition of a unique fiber draw tower that allows custom design of high-purity fiber optics. Earlier this year the program launched new partnerships with the DoD’s High Energy Laser Joint Technology Office in research and development programs that include the MIT Lincoln Laboratory.
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