Abstract

Ultra long haul multi-Gbit/s transmission systems using Erbium-Doped Fiber Amplifiers (EDFAs) as transparent in-line repeaters have been intensively pursued [1][2], In these systems, it is important to develop a supervisory (SV) signal transmission technique between in-line repeaters and terminals. A wavelength division multiplexing (WDM) technique is one way to provide a SV channel, and a pump power modulation technique [3] is another way. A WDM technique requires, however, another laser for a SV transmission. We first found experimentally that pump power modulation could provide a SV channel even in the absence of a line signal by making use of amplified spontaneous emission (ASE) of EDFAs as a SV signal source. We discuss here the possibility of ASE modulation and show an experimental result which successfully demonstrates a 10,000km SV signal transmission using a recirculating fiber loop.

© 1993 Optical Society of America