Erbium-doped optical fibers are designed using the refractive index difference, fiber core diameter and Er concentration as parameters in the numerical calculations. The fibers are fabricated with modified chemical vapor deposition and solution doping techniques, which are described in detail. Preform and fiber parameters also measured at several laboratories participating in the European Community's COST 217 project are given and compared with the fiber design values. The produced Er fiber is utilized in prototype fiber amplifiers. The differential efficiency of an Al-doped Er fiber is measured to be 77%.