DESIGN AND PERFORMANCE OF AN UNDERSEA, SINGLE-FIBER MULTI-REPEATER, FULL DUPLEX, ELECTRO-OPTICAL DATA LINK

Abstract

Fiber optics’ major contributions to undersea communications should include greater telemetry bandwidth, improved data precision and a decrease of system volume. The last two of these served as primary goals during recent design, fabrication and ocean testing of an undersea, electro-optical (E-O) telemetry system. The system’s total length was nearly 70 km. It contained 8 in-line repeaters which were powered through the E-O cable. Data were transmitted full duplex (22 MB/s at 0.83 μm & 43 KB/s at 1.06 μm through a single optical fiber. Power consumption was 1.69 watts for each repeater. Telemetry BER through the 70-km cable path was better than 10^-9 at 22 MB/s. The repeater housings were designed for 1-km ocean depths. Their dimensions (including bend-limiting cable terminations) were 2.88-cm diameter by 30.5 cm length. Each repeater contained special circuitry so that it would be queried from shore in a fault diagnosis mode. Designs and performance are reported for the E-O telemetry system and for its major components.