Abstract

In recent years several single-channel transoceanic amplified lightwave systems have been deployed. These systems have additional capacity that can be mined using wavelength-division multiplexing (WDM) [1]. In this paper a method is demonstrated to compute the concatenated gain profile, and hence the maximum WDM upgrade capacity of a long amplified system from measurements of the system’s output noise with no input signal. No equipment is needed at the transmitter end. Estimates of the amplifiers’ average saturation power, noise figure, and of the fiber loss are required. Determination of the overall gain of the amplifier chain allows prediction of the signal- to-noise ratio (SNR) penalty for any distribution of the channels’ input power in a WDM optical communication system and therefore of the maximum number of channels, and total capacity, that can be transmitted for a given SNR penalty [2].

© 1996 Optical Society of America