Analytical Model of Erbium-Doped Fiber Amplifiers Pumped at 1480 nm

Geguo Du, Chen Guofu

G.R. Khan

XIAGuangqiong, CHENJian-guo

Modeled with a three-level-atom appropriate to 980nm pumped ampifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been specified.

Michael J. Yadlowsky, Leslie J. Button

Summary form only given. Recently it has been shown that small changes in pump wavelength within the 980-nm pump band change the shape of the gain spectrum of erbium-doped fiber amplifiers (EDFAs). These gain variations can be as large as 3 dB in a typical line amplifier and cannot be explained by the well known homogeneous model for EDFAs. Pump-induced gain changes must be accounted for in multiwavelength amplifiers and systems operating over the pump-wavelength-sensitive short-wavelength portion of the erbium gain band. In this paper, we compare the impact of pump-mediated inhomogeneities on the gain spectra of EDFAs pumped in the 1480- and 980-nm pump bands. We find that the shape of the EDFA gain spectrum is less affected by changes in pump wavelength in the 1480-nm band, and show that in both cases the dynamic gain tilt function (DGTF) is relatively insensitive to changes in pump wavelength. The latter indicates that inversion-induced gain changes can be predicted from a (measured) DGTF despite pump band and some signal band inhomogeneities. We present fluorescence line narrowing measurements that explain these results and suggest a physical mechanism for 980-nm band pump-mediated inhomogeneities.

P. C. Becker, N.A. Olsson, J.R. Simpson

Bernard Calvas, Paul Urquhart

A model is presented for erbium-doped fiber amplifiers that operate by an upconversion process in which two pump photons at ~800 nm are absorbed and can provide an inverted population and hence the ability to amplify signal photons at ~850 nm. The most important spectroscopic features of the amplifier are identified and used to formulate a theory that predicts how the amplifier gain varies with fiber length and doping density, as well as with launched pump and signal powers. The limitation that amplified spontaneous emission imposes on the gain is investigated, and useful approximate formulas are derived in the limit where amplified spontaneous emission is negligible.