By concatenating an aluminum-codoped erbium-doped fiber with an efficient erbium/ytterbium-codoped fiber, we produce a gain spectrum that is f lat within 0.5 dB for 17 nm from 1544 to 1561 nm. By using energy transfer between erbium and ytterbium ions, we are able to pump the second stage with a high-power 1064-nm source to achieve an output power as high as +26 dBm. Using 980-nm pumping of the first stage, we produce an overall noise figure below 5 dB.
© 1996 Optical Society of America
Paul F. Wysocki, Namkyoo Park, and David DiGiovanni, "Dual-stage erbium-doped, erbium/ytterbium-codoped fiber amplifier with up to +26-dBm output power and a 17-nm flat spectrum," Opt. Lett. 21, 1744-1746 (1996)