Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 19: Ultrashort Laser Pulses: Generation III

Q 19.8: Talk

Tuesday, March 9, 2010, 15:45–16:00, F 342

Mode-locking maps of passively mode-locked Erbium fiber lasers — •Tim Hellwig, Till Walbaum, Petra Gross, and Carsten Fallnich — Institut für Angewandte Physik, Westfälische Wilhelms-Universität Münster, Deutschland

Passive mode-locking by nonlinear polarization rotation provides the shortest pulses from fiber lasers up to date. Full characterization of the polarization dependence of the mode-locking behaviour could lead to a better understanding of the mode-locking mechanism and should improve the application of fiber lasers as turn-key ultrashort pulsed sources.

We utilize a real-time, all-fiber division-of-amplitude polarimeter to monitor the intracavity polarization of an Erbium fiber laser taking advantage of a calibration scheme with intracavity polarization controllers. For the first time to the best of our knowledge, fully automated scans covering the whole Poincaré sphere were performed, leading to the observation of mode-locking regimes which differ in output power and pulse duration. Mode-locking is identified on-line using two-photon absorption in a photodiode and can be distinguished from hybrid operation modes. Dependence of the mode-locking maps on laser parameters (e.g. spectral filtering or dispersion) as well as on environmental influences is expected and subject of current investigations.