Abstract: A Raman amplifier includes at least a first and a second optical Raman-active fiber disposed in series with each other. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of said first and second group of frequencies extends over a pump frequency range having a width of at least the 40% of the Raman shift. The minimum and the maximum frequency in each of said first and second group of frequencies differ with each other of at most the 70% of said Raman shift.

Abstract: A Raman amplifier includes at least a first and a second optical Raman-active fiber disposed in series with each other. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of said first and second group of frequencies extends over a pump frequency range having a width of at least the 40% of the Raman shift. The minimum and the maximum frequency in each of said first and second group of frequencies differ with each other of at most the 70% of said Raman shift.

Abstract: A Raman amplifier comprises at least a first and a second optical Raman-active fiber disposed in series with each other. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of said first and second group of frequencies extends over a pump frequency range having a width of at least the 40% of the Raman shift. The minimum and the maximum frequency in each of said first and second group of frequencies differ with each other of at most the 70% of said Raman shift.

Abstract: A Raman amplifier comprises at least a first and a second optical Raman-active fiber disposed in series with each other. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of said first and second group of frequencies extends over a pump frequency range having a width of at least the 40% of the Raman shift. The minimum and the maximum frequency in each of said first and second group of frequencies differ with each other of at most the 70% of said Raman shift.

Abstract: A Raman amplifier having at least a first and a second optical Raman-active fiber disposed in series with each other is disclosed. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of the first and second group of frequencies extends over a pump frequency range having a width of at least 40% of the Raman shift. The minimum and the maximum frequency in each of the first and second group of frequencies differ from each other by at most 70% of the Raman shift.

Abstract: A Raman amplifier having a microstructured fiber and at least one pump laser, optically connected to one end of the microstructured fiber. The pump laser is adapted for emitting a pump radiation at a wavelength ?p, and the microstructured fiber has a silica-based core surrounded by a plurality of capillary voids extending in the axial direction of the fiber. The core of microstructured fiber has at least one dopant added to silica, the dopant being suitable for enhancing Raman effect.

Abstract: A Raman amplifier having at least a first and a second optical Raman-active fiber disposed in series with each other is disclosed. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of the first and second group of frequencies extends over a pump frequency range having a width of at least 40% of the Raman shift. The minimum and the maximum frequency in each of the first and second group of frequencies differ from each other by at most 70% of the Raman shift.

Abstract: A Raman amplifier having a microstructured fiber and at least one pump laser, optically connected to one end of the microstructured fiber. The pump laser is adapted for emitting a pump radiation at a wavelength ?p, and the microstructured fiber has a silica-based core surrounded by a plurality of capillary voids extending in the axial direction of the fiber. The core of microstructured fiber has at least one dopant added to silica, the dopant being suitable for enhancing Raman effect.