Patent ID: 6104733
Filing Date: 2000-08-15
Classification: H01S

Abstract:
An article comprising a fiber optic telecommunication amplifier comprising a cladding-pumped fiber amplifier comprising:a) at least one pump laser adapted for providing a continuous wave pump radiation of wavelength .lambda..sub.p ;b) a length of cladding-pumped fiber having a Er/Yb-doped core, said core being surrounded by an inner cladding and an outer cladding, said inner and outer claddings selected such that the cladding pumped fiber is a multimode fiber at wavelength .lambda..sub.p ;c) a signal radiation coupler for coupling a signal radiation into said core at a first end of the length of cladding-pumped fiber;d) a pump radiation coupler for coupling at least a part of the continuous wave pump radiation into said inner cladding of the cladding-pumped fiber wherein;e) the length of cladding-pumped fiber has a second end for providing signal radiation for utilization; andf) the fiber optic telecommunication amplifier further comprises a fiber optic Er-doped preamplifier disposed upstream of said first end of the length of cladding pumped fiber and disposed to receive said signal radiation and to emit amplified signal radiation that is coupled into the first end of the cladding-pumped fiber by the signal radiation coupler;CHARACTERIZED IN THATg) the fiber optic Er-doped preamplifier is selected to provide to the first end of the length of cladding pumped fiber amplifier an input signal power of more than 10 dBm, whereby the fiber optic telecommunication amplifier has a conversion efficiency of at least 25%, where ""conversion efficiency"" is the ratio of the output signal power to the input pump power.