A rare earth doped optical fiber amplifier is configured to have an enlarged core region and a trench formed adjacent to the core, where at least an inner portion of the trench is also formed to include a rare earth dopant. The presence of the rare earth dopant in the inner region of the cladding minimizes transient power fluctuations within the amplifier as the number of optical signals being amplified changes. The addition of rare earth dopant to the cladding increases the overlap between the pump, signal and the rare earth ions and thus improves the gain efficiency for the optical signal. The relatively large core diameter increases the saturation power level of the rare earth dopant and decreases the transients present in the gain as the input signal power fluctuates.