communications experts at the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., are asking industry to develop a blue-spectrum submarine laser communications system able to link submerged submarines with nearby aircraft for anti-submarine warfare (ASW).
The Los Angeles class fast-attack submarine USS Hartford (SSN 768)
DARPA issued a broad agency announcement Friday (DARPA-BAA-10-25) for the Tactical Relay Information Network (TRITON) research program to develop a blue-laser submarine communications system quickly enough to test during the U.S. Navy Rim of the Pacific (RIMPAC) exercise in June 2012.
The submarine laser communications prototype must meet Technology Readiness Level 6 (TRL-6), should help DARPA scientists validate improvements in blue lasers, and must demonstrate this technology's ability to link submarines and aircraft while the submarines are submerged and underway.
The TRITON project is to build on technology DARPA developed in the 1990s under the Tactical Airborne Laser Communications (TALC), which tested blue-green laser communications to link submerged submarines with Navy P-3 maritime patrol aircraft. TALC matched a blue laser to a cesium atomic line resonance receiver at 455.6 microns; the downlink was a green diode-pumped laser compatible with existing submarine receivers at 532 microns.
The Navy is interested in submarine laser communications to reduce reliance on towed-buoy receivers, to enhance the communications reliability and data throughput to ballistic missile submarines, and to enhance coordination among aircraft and fast attack submarines for ASW.
TRITON seeks to overcome the limitations that sunlight poses to submarine laser communications, which requires a high peak power laser and an optical filter with narrow spectral bandwidth, high transmission, and wide-field-of-view.
Both components must operate in the oceans' blue-green optical window, with blue being better in clear water in the open ocean (Jerlov type IB/II), and green being better in murky coastal waters (Jerlov type III).
The TRITON submarine laser communications prototype should be composed of the uplink and downlink transceivers, using an aircraft as a surrogate satellite/medium-to-high altitude aircraft platform.
The TRITON program will be in three phases, with a total program cost of about $39 million. (Source mae.pennnet)