Disclosed is a fiber amplifier system including a gain fiber having a single-mode core doped with active dopant ions capable of producing stimulated emission of light at wavelength λ s when pumped with light of wavelength λ p . Spliced to the gain fiber is a light-attenuating fiber having a core containing a dopant that attenuates light of wavelength λ p but not λ s . The amplifier is conventionally employed in a system including an incoming telecommunication fiber for introducing light of wavelength λ s into an end of the gain fiber, the amplified signal being connected to an outgoing telecommunication fiber. The system further includes a pump source for introducing light of wavelength λ p into an end of the gain fiber. Elements of the system can be arranged for forward pumping, counter pumping and dual ended pumping.
Various interconnection schemes are disclosed for forming a series arrangement including the gain fiber, the attenuating fiber and the outgoing fiber.