Hannover 2013 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 16: Photonics II

Q 16.1: Talk

Monday, March 18, 2013, 16:30–16:45, A 310

Experimental demonstration and control of pulsed modulation instability in a microstructured fiber — •Maximilian Brinkmann, Michael Kues, and Carsten Fallnich — Institut für Angewandte Physik, Westfälische Wilhelms-Universität, Corrensstr. 2, 48149 Münster

Modulation instability refers to the process in which a weak perturbation of an electromagnetic wave is exponentially amplified due to a nonlinear phase matching condition. The process is known to affect cw-signals in optical fibers and leads to the generation of multiple sidebands symmetrically spaced around the pump frequency. The effect also plays an important role in the initial stage of fiber supercontinuum (SC) generation with pulsed laser sources. However, so far only one pair of sidebands has been observed using pulsed laser sources, namely at the maxima of the gain curve. Here we report the generation of multiple sidebands in a microstructured fiber using only a short (few ps) chirped pump pulse in combination with a frequency-shifted weak seed pulse acting as a perturbation. The seed pulse is extracted from a prior formed SC. The generated sidebands have a minimum 3-dB linewidth of 2 THz, span over the whole parametric gain-spectrum of the pump (more than 300 THz) and can be shifted as close to the pump as 10 THz. The exact frequency and power of the sidebands can be simply controlled via the power and frequency of the seed. Thereby this technique bears the potential to be used as a multiwavelength laser pulse source. The experimental results agree with simulations based on the nonlinear Schrödinger equation and with analytic expressions.