| Date |
Do, 05.12.2013 - Do, 05.12.2013 |
| Time |
10.15 |
| Speaker |
Dereje Etissa, Institute of Applied Physics, University of Bern |
| Location |
Universität Bern, Institut für Angewandte Physik, Gebäude exakte Wissenschaften, Hörsaal B77, Sidlerstrasse 5, 3012 Bern |
| Program |
In 1961, Elias Snitzer and colleagues constructed and operated the world's first fiber optical amplifier. The real breakthrough of fiber optic amplifiers was then achieved in 1987 by the invention of the erbium-doped fiber amplifier that allowed long-haul intercontinental fiber optic communication. Since then, the optical output power of fiber optic amplifiers and fiber laser has increased dramatically, enabled by the invention of specialty optical fibers with always larger cores. However the upper limit is still not reached. The Optical Fibers and Fiber Lasers group also participates in the fabrication of innovative optical fibers and operates a fiber drawing tower. Our approach is based on the unique granulated silica method, offering great simplification of manufacturing optical fibers with a large variety of dopants, choice of index distributions, flexible fiber geometries and dopant concentrations. This is especially true if the solgel method is used to produce the doped granulated silica. In particular, the sol-gel method allows the inclusion of P2O5 and thus, in combination with Al2O3, higher dopant concentration of active rare earths such as Ytterbium is possible. The price one has to pay for these advantages over standard preform and fiber production techniques are the intrinsically higher OH content and the high scattering losses. However, both disadvantages are of low importance in applications where only short fiber lengths are involved, such as fiber lasers and amplifiers. In this talk the state of the art of our granulated silica method is presented as well as the last progresses in the production of rare earth doped optical fibers. |
| Download |
 (75 KB) |
|
(75 KB) |
| Link |
www.iap.unibe.ch |
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