A fiber optic telemetry system for multiple oceanographic platforms

The need to move large volumes of data and control signals between an instrument complex and command center for such diverse oceanographic systems as a remotely controlled deep towed survey sled, a tethered ROV test vehicle and a multi-sensor shallow water observatory complex have lead to the development of a versatile high speed fiber optic telemetry system for use with a broad range of sensors and system architecture´s. Since this telemetry system is intended to provide communications between a wide variety of oceanographic sensors, such as analog sonar, high resolution electronic still cameras and Ethernet, it has been designed to be modular, with the use of plug in circuit cards comprising the interface to specific sensors. With a full duplex usable capacity of 100 megabits per second in each direction, the telemetry system will operate over a pair of single mode or multi mode fibers, and with the addition of a wave division multiplexer, single fiber bi-directional operation is possible. This paper provides an overview of the design considerations used to develop the telemetry system which has broad applications in oceanographic data acquisition and control. Originally developed for a deep towed imaging vehicle operated by the Naval Oceanographic Office, the telemetry system provides the user with many simultaneous independent data channels, each with deterministic transit time and low latency. Inherent modularity of the fundamental fiber optic telemetry system design gives the vehicle operators the flexibility to upgrade or add new sensors to the tow sled as their requirements dictate. This versatility is demonstrated by showing the use of the telemetry In the tethered ROV TROV, and as the communication link currently operating between the LEO-15 seafloor observatory off the cost of New Jersey and the LEO shore station at the Rutgers University facility in Tuckerton