We present an erbium-doped dispersion-compensating fiber made up of two asymmetric concentric cores, inner and outer matched claddings, and erbium located in the central core only. We demonstrate a high negative chromatic dispersion value [-700 ps/(nm km) at 1568 nm], significant modification of the gain spectrum compared with that of a classic erbium-doped fiber amplifier, and 30-dB peak small-signal gain at 1535 and 1553 nm.