Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5368178 | Applied Surface Science | 2007 | 5 Pages |
Optical multimode fibers are applied in materials processing (e.g. automotive industry), defense, aviation technology, medicine and biotechnology. One challenging task concerning the production of multimode fibers is the enhancement of laser-induced damage thresholds. A higher damage threshold enables a higher transmitted average power at a given fiber diameter or the same power inside a thinner fiber to obtain smaller focus spots.In principle, different material parameters affect the damage threshold. Besides the quality of the preform bulk material itself, the drawing process during the production of the fiber and the preparation of the fiber end surfaces influence the resistance. Therefore, the change of the laser-induced damage threshold of preform materials was investigated in dependence on a varying thermal treatment and preparation procedure.Single and multi-pulse laser-induced damage thresholds of preforms (F300, Heraeus) were measured using a Q-switched Nd:YAG laser at 1064Â nm wavelength emitting pulses with a duration of 15Â ns, a pulse energy of 12Â mJ and a repetition rate of 10Â Hz. The temporal and spatial shape of the laser pulses were controlled accurately.Laser-induced damage thresholds in a range from 150Â JÂ cmâ2 to 350Â JÂ cmâ2 were determined depending on the number of pulses applied to the same spot, the thermal history and the polishing quality of the samples, respectively.