Abstract: The invention consists in an amplifying optical fiber comprising a core containing a dopant and a cladding, wherein said core comprises a monomode core intended to propagate an optical signal, quantum dots of a semiconductor material being disposed in or near said monomode core, and a multimode core surrounding the monomode core, intended to receive a pumping signal.

Abstract: The invention consists in an amplifying optical fiber comprising a core containing a dopant and a cladding, wherein said core comprises a monomode core intended to propagate an optical signal, quantum dots of a semiconductor material being disposed in or near said monomode core, and a multimode core surrounding the monomode core, intended to receive a pumping signal.

Abstract: The invention consists in an amplifying optical fiber comprising a core containing a dopant and a cladding, wherein said core comprises a monomode core intended to propagate an optical signal, quantum dots of a semiconductor material being disposed in or near said monomode core, and a multimode core surrounding the monomode core, intended to receive a pumping signal.

Abstract: The invention proposes a double-clad photonic optical fiber presenting: a fiber core, first cladding surrounding the fiber core, and second cladding surrounding the first cladding; at least one hole in the fiber core; and doping using a rare earth ion, at least in the core of the fiber. The invention makes it possible to obtain a double-clad fiber with good overlap between the signal and a pump injected into the core. It improves amplification efficiency in double-clad optical amplifiers where the signal is injected into the core of the fiber and the pump into the first cladding.

Abstract: An optical signal amplifier comprises a Semiconductor Optical Amplifier SOA used as semiconductor Amplified Spontaneous Emission ASE source. This SOA produces optical pumping seed which has to be amplified to get a large pump power. With such large pump power, it will be possible to counteract the loss in a fiber link of optical signals transmitted through it by applying said amplified pumping seed as Raman amplification on the optical signals. The invention further relates to a method for amplifying an optical signal comprising the combination of a semiconductor ASE source together with a high-power pump source. Latter will be used to amplify optical pumping seed to be produced by the semi-conductor ASE source. Accordingly, the obtained amplified pumping seed will be used to act as a Raman amplification of optical signals.

Abstract: The invention consists in an amplifying optical fiber comprising a core containing a dopant and a cladding, wherein said core comprises a monomode core intended to propagate an optical signal, quantum dots of a semiconductor material being disposed in or near said monomode core, and a multimode core surrounding the monomode core, intended to receive a pumping signal.

Abstract: The present invention provides a WDM optical communication system, comprising input means and output means for an optical signal, an optical fibre path connecting signal-transmissively said input and output means, wherein the optical signal is amplified by means of Raman amplification and said optical fibre path comprises at least one Raman amplifier, further comprising WDM means for coupling at least two polarized pump radiation wavelengths with wavelengths less than the signal radiation wavelength into said Raman amplifier, wherein one pump radiation wavelength has a selected different polarization with respect to the polarization of the other pump radiation wavelengths.

Abstract: A two-stage Raman amplifier provides a gain control compensating for span loss variations and changing channel loading. A first amplifier stage (S1) has a first amplifying medium (F1) and a first pump light source (P1, P2, Pn), which is controlled and adjusted by a control unit (CU) to compensate for span loss variations. A second amplifier stage (S2) has a second amplifying medium (F2) and a second pump light source (P?1, P?2, P?n), which is controlled and adjusted by the control unit (CU) to balance changing channel loading.

Abstract: The invention is related to an optical amplifier connected to a pump laser with lengths of fibers and isolators between the lengths of fibers. The invention is also related to a transmission system using this amplifier and in addition the invention gives also a rule to optimize the position of isolators in a amplifier.

Abstract: A Raman amplifier (10) including at least one amplifying fiber (12) and a coupler (14) for coupling at least first (16) and second (18) pump laser modules to the amplifying fiber (12), the first pump laser module (16) including a frequency discriminator (24) for selecting an optical frequency to be emitted with an optical power exceeding an optical power of remaining optical frequencies that are also emitted by the first pump laser module (16). The first optical frequency is spaced apart from a local maximum (28; 36; 48) in optical power of the remaining optical frequencies, and the second pump laser module (18) emits at an optical frequency one Stokes-frequency above the frequency of the local maximum (28; 36; 48). The first optical frequency and the frequency of the local maximum are chosen on Stokes-frequency above the signal frequency range. As a consequence, the Raman gain provided in the Raman amplifying fiber 12 is broadened.

Abstract: The invention is related to a parametric amplifier connected to a pump laser with a control device for adapt the pump laser. This amplifier is used in a transmission system. In addition the invention comprises a method for controlling the pump laser source in an iterative process to optimize the gain of the amplifier.

Abstract: An optical amplifier is proposed which has an optical waveguide structure) through which signal light and pump light are propagated. The optical waveguide structure has a core with a relatively high refractive index and a clad with a relatively low refractive index, where at least said core exhibits a nonlinear response of second or third order. In a result optical parametric amplification of said signal light is achieved. The amplifier has separate idler light filters for attenuating idler light, which is generated in the process of optical parametric amplification, The position of the idler light filters can be defined placed in said optical waveguide structure at a defined length Lmax.

Abstract: An optical fiber amplifier is considered comprising a mono-mode core, a first cladding around said core and at least a further cladding around said first cladding while said first cladding includes a ring shaped active region doped with rare earth material surrounding said mono-mode core. Advantageously, the first cladding is designed with a radial refractive index following an almost continuous decreasing function for increasing radius. The use of a continuously decreasing refractive index for the cladding at the outer border of the ring shaped active medium optimize the efficiency of the coupling between the core and the cladding.

Abstract: A two-stage Raman amplifier provides a gain control compensating for span loss variations and changing channel loading. A first amplifier stage (S1) has a first amplifying medium (F1) and a first pump light source (P1, P2, Pn), which is controlled and adjusted by a control unit (CU) to compensate for span loss variations. A second amplifier stage (S2) has a second amplifying medium (F2) and a second pump light source (P?1, P?2, P?n), which is controlled and adjusted by the control unit (CU) to balance changing channel loading.

Abstract: The invention is related to a parametric amplifier connected to a pump laser with a control device for adapt the pump laser. This amplifier is used in a transmission system. In addition the invention comprises a method for controlling the pump laser source in an iterative process to optimize the gain of the amplifier.

Abstract: The present invention relates to a cascaded multi-wavelength Raman fiber laser adapted for emitting radiation of at least one wavelength &lgr;s1, with a length of optical fiber (13) having input (15) and output (16) sections, means (11) for introducing pump radiation of wavelength &lgr;p into said length of optical fiber (13), at least one pair of spaced-apart reflector means (151,161; . . .

Abstract: The invention is related to an optical amplifier connected to a pump laser with lengths of fibers and isolators between the lengths of fibers. The invention is also related to a transmission system using this amplifier and in addition the invention gives also a rule to optimize the position of isolators in a amplifier.

Abstract: An optical fiber with a large effective surface area has holes at points in at least two layers concentric with the fiber of points of a regular matrix. The holes in one layer have the same dimensions and occupy all the available points in the layer. In at least two layers the holes have different dimensions and there is at least one layer with no holes.

Abstract: An optical fiber with a large effective surface area has holes at points in at least two layers concentric with the fiber of points of a regular matrix. The holes in one layer have the same dimensions and occupy all the available points in the layer. In at least two layers the holes have different dimensions.

Abstract: An optical signal amplifier comprises a Semiconductor Optical Amplifier SOA used as semiconductor Amplified Spontaneous Emission ASE source. This SOA produces optical pumping seed which has to be amplified to get a large pump power. With such large pump power, it will be possible to counteract the loss in a fiber link of optical signals transmitted through it by applying said amplified pumping seed as Raman amplification on the optical signals. The invention further relates to a method for amplifying an optical signal comprising the combination of a semiconductor ASE source together with a high-power pump source. Latter will be used to amplify optical pumping seed to be produced by the semi-conductor ASE source. Accordingly, the obtained amplified pumping seed will be used to act as a Raman amplification of optical signals.