6924928

Claims

• 1. An amplifier comprising: an optical gain fiber; a pump source that generates a pump light; and means for introducing the pump light into the optical gain fiber; wherein the optical gain fiber comprises a modified silica glass providing a reduction in the multiphonon quenching for a rare-earth dopant; wherein said modified silica glass comprises SiO2, in a host material, a rare-earth oxide dopant selected from the group consisting of Tm3+, Ho3+ and Tm3+ sensitized-Ho3+, and a first SiO2 modifier; and wherein said first modifier is a 3+ cation dopant and is selected from the group consisting of Ga, Y, and combinations thereof, such that said first modifier reduces multiphonon quenching of said rare-earth dopant contained therein. 2. An amplifier as claimed in claim 1, wherein the modified silica glass further comprises: a second SiO2 modifier; and wherein said second modifier concentration is between about 0.1 and about 10 molar percent of said second modifier in said host material such that said first modifier d said second modifier reduce multiphonon quenching of said rare-earth dopant contained therein. 3. An amplifier as claimed in claim, 1 wherein said concentration of SiO2 is between about 70 and about 99 molar percent SiO2 in said host material; wherein said rare-earth concentration is between about 100 and about 100,000 ppm by weight of said rare-earth oxide in said host material; and wherein said first modifier concentration is between about 0.1 and about 20 molar percent of a first modifier in said host material. 4. An amplifier as claimed in claim 2, wherein said second modifier is a 5+ cation dopant. 5. An amplifier as claimed in claim 2, wherein said second modifier is selected from the group consisting of Ta5+, Bi5+ and combinations thereof. 6. An amplifier as claimed in claim 1, further comprising an input optical fiber and an output optical fiber coupled to the optical gain fiber. 7. An amplifier as claimed in claim 1, wherein the amplifier provides amplification in the S-band. 8. An amplifier as claimed in claim 1, wherein the means for introducing the pump light includes a pump combiner. 9. An amplifier as claimed in claim 1, wherein the optical gain fiber is coupled to at least one of the input optical fiber, the output optical fiber and the means for introducing a pump light by a fusion splice. 10. An amplifier as claimed in claim 1, wherein the amplifier operates on the 3H4→3F4 transition. 11. An amplifier as claimed in claim 1, wherein the amplifier operates an the 3H4→3H6 transition. 12. An amplifier as claimed in claim 1, wherein the amplifier operates on the 1G4→3F2 transition. 13. An amplifier as claimed in claim 1, wherein the amplifier operates on the 3F4→3H6 transition.