Patent ID: 7440165

Claim:
An optical fiber comprising: a core containing a first doping element at a concentration of about 10 mol % to about 20 mol % wherein the first doping element is not a rare earth element; a cladding containing a second doping element at a concentration of about 0.000004 mol % to about 0.0004 mol % (which corresponds to about 1×10 15 cm −3 to about 1×10 17 cm −3 , respectively) wherein the second doping element is a rare earth element; and a composition material of the optical fiber is not the first and second doping elements, wherein the core containing the first doping element being configured to produce non-linear Raman stimulated gain at a first spectral band having a first gain when the core containing the first doping element is stimulated by at least one pumping source having a single wavelength, the pumping source having a wavelength between about 1,380 nm to about 1,420 nm, and wherein the cladding containing the second doping element being configured to produce direct-transition light amplification phenomenon at a second spectral band having a second gain when the cladding containing the second doping element is stimulated by the at least one pumping source, wherein the first spectral band has a wavelenath range of 1,490 nm to 1,530 nm (S-band), and wherein the second spectral band has a wavelength range of 1,530 nm to 1,570 nm (C-band).