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Fabrication and evaluation of a 500 W cladding-light stripper

 
: Kliner, Andrea; Hou, Kai-Chung; Plötner, Marco; Hupel, Christian; Stelzner, Thomas; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

:

Piyawattanametha, W. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
MOEMS and Miniaturized Systems XII : 2.-7.2.2013, San Francisco, CA, USA
Bellingham, WA: SPIE, 2013 (Proceedings of SPIE 8616)
ISBN: 978-0-8194-9385-9
Paper 86160N
Conference "MOEMS and Miniaturized Systems" <12, 2013, San Francisco/Calif.>
English
Conference Paper
Fraunhofer IOF ()
cladding-light stripper; double clad fiber; fiber laser components; high power

Abstract
Fiber lasers have reached kW levels of output power. To achieve this level it is necessary to use reliable high-power components that sustain these power levels. Double-clad fibers (DCFs) are often used in high-power fiber lasers. Cladding-light strippers (CLSs) are used to remove unwanted light from the inner cladding of the DCF. This unwanted light consists of residual pump light or signal light that leaked into the cladding, thus requiring that the CLS removes both high-NA (>0.4) and low-NA (<0.1) light. Often high-index polymers are used to remove the unwanted light from DCFs1,2,3. Because the CLS has to be able to withstand several 100W and most polymers are not capable of exceeding temperatures more than 200°C, we investigated a CLS without polymers, based on an etching process. We present results from a CLS that was tested up to 500W of stripped power. We determined the angle dependency of the stripping efficiency by launching both high- and low-NA light into the fiber and evaluating the NA attenuation. Furthermore, we measured the dependency of the stripping efficiency on the length of the etched area and the etching time. With optimized parameters an attenuation of more than 20 dB when launching high-NA light and 6 dB with low-NA light was achieved. The CLS did not show any degradation in terms of attenuation or thermal behavior in a six-hour stability test.

: http://publica.fraunhofer.de/documents/N-237804.html