Patent ID: 8509588

Claim:
An amplifying optical fiber operating at a wavelength in the range of 1000-1700 nm, comprising: an oxide glass core devoid of rare-earth elements and containing oxides of elements selected from the group consisting of silicon, germanium, phosphorus, aluminum, gallium, and providing optical amplification, and at least one oxide glass cladding, said optical fiber characterized in that: the core contains oxides of elements selected from the group consisting of silicon, germanium, phosphorus, bismuth, aluminum, gallium with a concentration of bismuth oxide of 10 −4 -5 mol %, a total concentration of silicon and germanium oxides of 70-99.8999 mol %; a total concentration of aluminum and gallium oxides of 0.1-20 mol % wherein both aluminum oxide and gallium oxide are present and a ratio of aluminum oxide to gallium oxide is at least two, and a concentration of phosphorus oxide of 0-10 mol %, and provides a maximum optical gain at least 10 times greater than a nonresonant loss factor in the optical fiber; the outside oxide glass cladding comprises fused silica; wherein the optical fiber core emits luminescence in the range of 1000-1700 nm when excited by a light with wavelengths in the range of 750-1200 nm, the half-height width of the luminescence band being more than 120 nm, luminescence band boundaries are defined as points in which the luminescence intensity drops twice relative to the intensity in the luminescence band maximum and lie within the spectral range of 1000-1700 nm, the core has an absorption band in the 1000 nm region, pumping to which region provides an increased power conversion of pump light into luminescence light in the 1000-1700 nm range as compared to pumping to another absorption bands.