Circulating loop transmission experiments for the study of long-haul transmission systems using erbium-doped fiber amplifiers

A circulating loop transmission experiment is a useful tool for the research and development of long-haul transmission systems that use erbium-doped fiber-amplifier repeaters. Circulating loop techniques, applied to an amplifier chain of modest length, can provide an experimental platform to study a broad range of transmission phenomena for EDFA-based transmission systems. A loop experiment attempts to simulate the transmission performance of a multi-thousand kilometer long system by reusing or recirculating an optical signal through a modest length amplifier chain of tens to hundreds of kilometers. This paper reviews original loop techniques developed to study various parameters of long-haul transmission using erbium-doped fiber-amplifiers repeaters for undersea systems. Transmission experiments were performed at transoceanic distances with 33 and 46 km amplifier spacing, operating at 5 and 10 Gb/s. Experimental data is provided here for various parameters, including bit error ratio, Q-factor, and spectral broadening.>