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AssigneeNippon Telegraph and Telephone Corporation
InventorsMakoto Yamada, Shinichi Aozasa, Tadashi Sakamoto, Atsushi Mori, Kouji Shikano, Makoto Shimizu
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New fiber lasers, spontaneous emission sources, and optical fiber amplifiers are provided. Their conventional counterparts, which have a fiber doped with thulium (Tm) ions and excited by 0.67 μm or 0.8 μm pumping light, have a problem in that their characteristics are deteriorated with the elapse of time. The new fiber lasers, spontaneous emission sources, and optical fiber amplifiers use 1.2 μm light as pumping light. Alternatively, they use a pumping source for exciting the thulium from the lowest energy level 3H6 to 3H5 excitation level. As a more preferable configuration, they improve the emission efficiency at 2.3 μm band by disclosing Tm-doped host glass.
A fiber laser using as a gain medium an optical fiber that has a core or a cladding doped with a rare-earth element having a laser transition level, wherein said optical fiber is doped with at least thulium;
A fiber laser using as a gain medium an optical fiber that has a core or a cladding doped with a rare-earth element having a laser transition level, said fiber laser having said optical fiber doped at least with thulium, and operating at 2.3 μm band, wherein said fiber laser uses 0.67 μm band or 0.8 μm band light as a pumping source, and said optical fiber doped at least with the thulium is a non-silica based fiber which uses, as host glass of said optical fiber, glass having a nonradiative relaxation rate which is caused by multi-phonon relaxation and is lower than a nonradiative relaxation rate of silica glass.
A spontaneous emission source using as a gain medium an optical fiber that has a core or a cladding doped with a rare-earth element having a laser transition level, wherein said optical fiber is doped with at least thulium;
A spontaneous emission source using as a gain medium an optical fiber that has a core or a cladding doped with a rare-earth element having a laser transition level, said spontaneous emission source having said optical fiber doped at least with thulium, and operating at 2.3 μm band, wherein said spontaneous emission source uses 0.67 μm band or 0.8 μm band light as a pumping source, and said optical fiber doped at least with the thulium is a non-silica based fiber which uses, as host glass of said optical fiber, glass having a nonradiative relaxation rate which is caused by multi-phonon relaxation and is lower than a nonradiative relaxation rate of silica glass.
An optical fiber amplifier using as a gain medium an optical fiber that has a core or a cladding doped with a rare-earth element having a laser transition level, wherein said optical fiber is doped with at least thulium;
An optical fiber amplifier using as a gain medium an optical fiber that has a core or a cladding doped with a rare-earth element having a laser transition level, said optical fiber amplifier having said optical fiber doped at least with thulium, and operating at 2.3 μm band, wherein said optical fiber amplifier uses 0.67 μm band or 0.8 μm band light as a pumping source, and said optical fiber doped at least with the thulium is a non-silica based fiber which uses, as host glass of said optical fiber, glass having a nonradiative relaxation rate which is caused by multi-phonon relaxation and is lower than a nonradiative relaxation rate of silica glass.
Dependencies are inferred from the claim text.