World War II ended in 1945 with the surrender of Germany and Japan, but it was an uneasy peace that followed. Although the U.S.S.R. had been America's ally during the war, after the war, the Soviet Union asserted control over eastern Europe, forming a communist bloc of nations hostile to the United States and western Europe. In the postwar years the United States and the Soviet Union emerged as the dominant world powers, locked in a philosophical conflict between democracy and communism. An arms buildup on both sides intensified the friction. This period of political hostility and military rivalry, which lasted several decades, is known as the cold war.
In this climate of tension with the Soviet Union, the U.S. Navy Underwater Sound Laboratory continued to conduct vital research, as it had during World War II. This research led to major advances in the ability to detect, track, and attack enemy submarines. The lab also developed increasingly sophisticated submarine communications technology.
The introduction of nuclear submarines and guided missiles into the military arsenal presented new challenges. The lab pursued ways to detect enemy submarines from greater distances, which required finding methods to reduce the obstruction of sound waves by the oceans' thermal layers. This led to a long-term project called AMOS (Acoustic, Meteorological, and Oceanographic Study). AMOS researchers measured and studied the properties of the oceans, such as currents, tides, and temperatures, and the effects of these properties on sonar.
Among its accomplishments in the field of electromagnetics, the lab played a crucial role in developing the navy's extremely low frequency (ELF) communications system, which allows submerged submarines to receive messages. Unlike other radio waves, extremely low frequency waves can travel through the ocean to depths of several hundred feet. The lab also conducted high-level research in periscope technology, developing periscopes that incorporated cameras and high-tech antennas.
The lab at Fort Trumbull underwent various official name changes over the decades, but it was always known locally as the "Sound Lab." In the 1990s the United States scaled back the military, after the breakup of the Soviet Union. The navy closed its lab here in the late 1990s and transferred all its operations to the Naval Undersea Warfare Center in Newport, Rhode Island.