Raman amplification using a microstructured fiber

A microstructured fiber suitable for guiding an optical signal having a wavelength lying in a wavelength band between 1460 and 1650 nm, comprising a core surrounded by a plurality of capillary voids extending in the axial direction of the fiber, said core comprising silica and a dopant suitable for enhancing Raman effect, said fiber being further suitable for guiding a pump radiation having a wavelength λpshifted with respect to at least one wavelength of said wavelength band in a lower wavelength region according to the Raman shift of said core, said fiber having a maximum Raman gain coefficient gR in said wavelength band, and an attenuation αp and an effective area Aeff at said wavelength λp, wherein said maximum Raman gain coefficient gR, said attenuation αp and said effective area Aeff are such that (gR/Aeff)/αp is greater than or equal to 5 1/W/dB.

A microstructured fiber comprising a core surrounded by a plurality of capillary voids extending in the axial direction of the fiber, said core comprising silica and germanium, wherein a concentration of germanium in said core is higher than or equal to 8%.

An optical transmission system comprising a transmitting station, a receiving station and an optical line between said transmitting station and said receiving station, said optical line comprising at least one Raman amplifier comprising at least one microstructured fiber and at least one pump laser, optically connected to one end of said microstructured fiber, said pump laser being adapted for emitting a pump radiation at a wavelength λp, said microstructured fiber comprising a silica-based core surrounded by a plurality of capillary voids extending in the axial direction of the fiber, said core comprising at least one dopant added to silica, said dopant being suitable for enhancing Raman effect.