Fiber Optic Towed Arrays

摘要

The current effort to bring the fiber optic towed array to production (designated the TB-33) is a joint effort involving Naval Undersea Warfare Center (NUWC), Chesapeake Sciences Corporation, General Dynamics, and NRL. NRL has played a critical role in developing the hydrophone design for this array and the interrogation/multiplexing approach used in the system. Unlike the AOTA demonstration and the Navy's fiber optic LightWeight Wide Aperture Array (currently in production), which are coupler-based systems, the TB-33 array uses low-reflectivity fiber Bragg gratings written in the fiber to define the sensors by forming low-reflectivity Fabry-Perot interferometers. The hydrophones are passively multiplexed both in time and in wavelength to allow hundreds of channels to be carried over just four optical fibers. This architecture is ideally suited to the towed array -- it minimizes the number of optical components in the array, which is critical to minimizing the diameter of the hydrophone core, and in turn allows a thicker hose wall to be used, thus increasing the durability and reliability of the array.