A detailed investigation of a state—space description of the dynamics of erbium doped optical fiber amplifiers (EDFAs) is provided. The description is used to derive equations that describe amplifiers that yield the greatest signal-to-noise ratio possible for a given gain. A further set of equations is derived to describe tapers that attain the greatest possible gain for a given input pump power. Numerical solutions of these equations are then examined, and it is thus shown that, in many important cases, fiber tapering can produce only a small signal-to-noise ratio improvement and a modest increase in the gain attainable for a given input.
© 1994 Optical Society of America
R. W. C. Vance and A. Ankiewicz, "State—space description of optimal erbium amplifier tapers," Appl. Opt. 33, 6992-7001 (1994)