Patent ID: 8009708

Claim:
An optical amplifier module, comprising: a first optical amplification waveguide mainly comprised of a silica glass, the first optical amplification waveguide including a ytterbium-doped first optical waveguide region which is co-doped with phosphorous; a second optical amplification waveguide optically coupled to the first optical amplification waveguide, the second optical amplification waveguide including a ytterbium-doped second optical waveguide region which is co-doped with aluminum, the second optical amplification waveguide being mainly comprised of a silica glass and having a dual-cladding structure; and a pumping unit supplying pumping light respectively to the first optical amplification waveguide and the second optical amplification waveguide, wherein the first and second optical amplification waveguides are arranged such that light to be amplified, having been inputted to the first optical amplification waveguide, propagates through the first optical amplification waveguide and then the second optical amplification waveguide successively, and the light to be amplified is amplified only once by means of the pumping light, in each of the first optical amplification waveguide and the second optical amplification waveguide, wherein a population inversion ratio of the first optical amplification waveguide is set higher than that of the second optical fiber amplification waveguide, and the first optical amplification waveguide has a pumping efficiency lower than that of the second optical amplification waveguide.