ACTIVE-FIBER OPTICAL AMPLIFIER AND YTTERBIUM DOPED FIBER THEREFOR

摘要

An optical amplifier and an active optical fiber therefor, particularly for optical fiber telecommunications lines, includes an erbium-doped, laser-emission, active optical fiber and a light pumping laser source operating at a predetermined wavelength. The active optical fiber further includes ytterbium as a further dopant, which further dopant exhibits an absorption of light at the emission wavelength of the pumping laser emitter, for example, a commercially available three-level diode-pumped laser of the Nd:YAG type, operating between 900 and 950 nm which is different from the wavelength at which erbium alone can be pumped. The further dopant is adapted to transfer the energy thus absorbed to the erbium contained in the fiber, thereby causing a population inversion thereof adapted to generate a stimulated light emission in the presence of an optical transmission signal. The use of ytterbium in the active fiber enables the achievement of a sufficiently wide spectrum of absorption so that the use of a laser of high power and low cost for the active fiber pumping within the amplifier is made possible.