S. T. Hwang, J. Nilsson, S. Y. Yoon, J. M. Kim, and S. J. Kim, "Gain-flattened erbium-doped fiber amplifier with a wide dynamic range in the 1542 ~ 1560-nm band,"
in Optical Fiber Communication Conference,
Vol. 2 of 1998 OSA Technical Digest Series
(Optical Society of America, 1998), paper WG3.