Large-scale remotely interrogated arrays of fiber-optic interferometric sensors for underwater acoustic applications

The fiber-optic interferometric acoustic sensor array has established itself as a potential alternative to the conventional sonar array based on electroceramic transducers. In this paper, we discuss all the aspects of a large-scale fiber-optic interferometric sensor array. We review the basic operating principles of the fiber-optic interferometric sensor, signal processing, and multiplexing techniques, we present results from a noise model for a full size system, and we determine the benefit of incorporating a remotely-pumped optical amplifier in the array. As a practical example we describe the design and construction of a prototype array with 96 hydrophones incorporating a remotely pumped erbium-doped fiber amplifier, called the fiber-optic bottom mounted array, which is based on a dense wavelength division and time division multiplexed architecture. These arrays have applications in military sonar and seismic surveying.