초록 ▼

According to some embodiments a few moded optical fiber includes a glass core structured to provide light amplification at an amplification wavelength and a cladding surrounding the core. According to some embodiments the core of the few moded optical fiber includes a portion that has an average con

According to some embodiments a few moded optical fiber includes a glass core structured to provide light amplification at an amplification wavelength and a cladding surrounding the core. According to some embodiments the core of the few moded optical fiber includes a portion that has an average concentration of rare earth dopant which is lower by at least 30%, and preferably by at least 50%, than the average concentration of the rare earth dopant at another portion of the core that is situated further from the core center.

대표청구항 ▼

1. A rare earth doped fiber comprising a glass core structured to provide light amplification at an amplification wavelength, a cladding surrounding the core, said fiber comprising: (i) the glass core having a radius R1 from about 3 μm to about 20 μm, a maximum relative refractive index delta Δ1MAX

1. A rare earth doped fiber comprising a glass core structured to provide light amplification at an amplification wavelength, a cladding surrounding the core, said fiber comprising: (i) the glass core having a radius R1 from about 3 μm to about 20 μm, a maximum relative refractive index delta Δ1MAX from about between 0.3% to 2% relative to the glass cladding, and refractive index profile of the core is structured such that the core is capable of supporting the propagation and amplification of an optical signal consisting only of the LP01 and LP11 modes at the amplification wavelength and said core does not support propagation and amplification of optical signals with-modes higher than the LP11 mode at the amplification wavelength;said core containing a rare earth dopant such that the average concentration of said rare earth dopant is at least 1.5 times lower in the portion of the core situated within 0Δ4MAX. 2. The rare earth doped fiber of claim 1 wherein said rare earth dopant is the rare-earth dopant is at least one of: Yb, Er, Nd, Tm, Sm, Gd, Pr, and Tb and wherein said gain wavelength is situated in one of the following wavelength bands: 625-640 nm, 940-1055 nm, 1280-1360 nm, 1440-1460 nm, 1490-1500 nm, 1540-1560 nm, 1645-1670 nm. 3. An optical fiber according to claim 1, wherein: the core is structured such that the core is capable of supporting the propagation and amplification of the optical signal at a wavelength within a wavelength range that is at least 20 nm wide and situated around a center wavelength of 1550 nm;the core containing Er2O3 such that the average concentration of Er2O3 is at least 2 times lower in the portion of the core situated within 0