Abstract: An optical fiber amplifier pumping technique based on multiple stimulated Raman scattering (SRS) for optical communication systems includes a plurality of pump signals with increasing wavelength which are injected into a fiber. The wavelengths of such pump signals are such that, in cascade, each pump signal of the plurality is amplified by the pump signal of wavelength immediately shorter, while it amplifies that with the wavelength immediately higher with the pump signal of highest wavelength which, in turn, pumps a remote rare earth doped optical fiber amplifier.

Abstract: A method of producing green light signals, comprising coupling pump signals from at least one pump source into at least one erbium doped fiber (EDF) which cause ground state absorption (GSA), and excited state absorption (ESA) in erbium ions of the EDF, which produces green light signals, wherein the majority of the pump signals have a wavelength at which the probability of occurrence of ESA in the EDF is greater than the probability of occurrence of GSA in the EDF. The majority of the pump signals may have a wavelength in the range approximately 920 nm to approximately 980 nm, or in the region of 960 nm. An erbium doped fiber amplifier (EDFA) (1) for amplifying traffic-carrying signals may be pumped by green light signals produced by this method.

Abstract: A system and method for controlling the gain of an optical amplifier receiving one or more optical input signal channels at a first end include a source for generating a gain control signal, which is input to the optical amplifier at the opposite end to the input signal channels. The gain control signal is generated at a power level that produces stimulated Brillouin scattering (SBS) in the optical amplifier.

Abstract: An optical fiber amplifier pumping technique based on multiple stimulated Raman scattering (SRS) for optical communication systems includes a plurality of pump signals with increasing wavelength which are injected into a fiber. The wavelengths of such pump signals are such that, in cascade, each pump signal of the plurality is amplified by the pump signal of wavelength immediately shorter, while it amplifies that with the wavelength immediately higher with the pump signal of highest wavelength which, in turn, pumps a remote rare earth doped optical fiber amplifier.

Abstract: A method of producing green light signals, comprising coupling pump signals from at least one pump source into at least one erbium doped fibre (EDF) which cause ground state absorption (GSA), and excited state absorption (ESA) in erbium ions of the EDF, which produces green light signals, wherein the majority of the pump signals have a wavelength at which the probability of occurrence of ESA in the EDF is greater than the probability of occurrence of GSA in the EDF. The majority of the pump signals may have a wavelength in the range approximately 920 nm to approximately 980 nm, or in the region of 960 nm. An erbium doped fibre amplifier (EDFA) (1) for amplifying traffic-carrying signals may be pumped by green light signals produced by this method.

Abstract: A Raman amplifier for amplifying WDM radiation propagating along an optical fiber, the WDM radiation comprising a plurality of radiation components each having a selected waveband, comprises a plurality of optical radiation generators operable to generate pump radiation of a selected wavelength and power, the radiation being coupled into the fiber to optically amplify the WDM radiation. The generators are wavelength tuneable, and the power of the radiation components of the WDM radiation is measured after it has propagated along the fiber and has been amplified. The wavelength and power of operation of the generators are controlled in dependence upon the measured powers such as to make the measured powers substantially equal in magnitude and of a selected magnitude.

Abstract: A system and method for controlling the gain of an optical amplifier receiving one or more optical input signal channels at a first end include a source for generating a gain control signal, which is input to the optical amplifier at the opposite end to the input signal channels. The gain control signal is generated at a power level that produces stimulated Brillouin scattering (SBS) in the optical amplifier.

Abstract: A method of producing green light signals couples pump signals from at least one pump source into at least one erbium doped fiber (EDF) to cause ground state absorption (GSA) and excited state absorption (ESA) in erbium ions of the EDF, which produces green light signals. The majority of the pump signals have a wavelength at which the probability of occurrence of ESA in the EDF is greater than the probability of occurrence of GSA in the EDF. The majority of the pump signals may have a wavelength in the range approximately 920 nm to approximately 980 nm, or in the region of 960 nm. An erbium doped fiber amplifier (EDFA) for amplifying traffic-carrying signals may be pumped by green light signals produced by this method.

Abstract: A Raman amplifier for amplifying WDM radiation propagating along an optical fiber, the WDM radiation comprising a plurality of radiation components each having a selected waveband, comprises a plurality of optical radiation generators operable to generate pump radiation of a selected wavelength and power, the radiation being coupled into the fiber to optically amplify the WDM radiation. The generators are wavelength tuneable, and the power of the radiation components of the WDM radiation is measured after it has propagated along the fiber and has been amplified. The wavelength and power of operation of the generators are controlled in dependence upon the measured powers such as to make the measured powers substantially equal in magnitude and of a selected magnitude.

Abstract: An optical fiber transmission system comprising a transmitter and a receiver at the two ends of an optical fiber. The transmitter comprises a signal laser for generation of a transmission signal and the receiver comprises a pump laser for production of a pump signal, which is incorporated in the fiber in a direction opposite to that of the transmission signal to obtain amplification using the Brillouin effect of the transmission signal. The central frequency, Fsign, of the transmission signal of the signal laser and the central frequency, Fpump, of the pump signal of the pump laser are such that (Fpump±20 MHz)?(Fsign±20 MHz)=10 GHZ±0.1 GHz, and the two lasers are controlled locally such that the maximum variation, ?fsign, of the central frequency of the transmission signal, the maximum variation, ?fpump, of the central frequency of the pump signal, and the bandwidth, Bfsign, of the transmission signal have the following relationship: Bfsign+?fsign+?fpump=100 MHz.