Mode-locked Ytterbium-doped fiber ring laser with 16 nJ pulse energy

In this paper, we present an ytterbium-fiber laser system with a cladding-pumped single-mode active fiber achieving mode-locking by nonlinear polarisation rotation. It consists of the following principal modules: A double-clad ytterbium fiber, quarter-(QWP) and half-wave-plates (HWP) for polarization control, an optical isolator for unidirectional laser operation and a dispersive delay line with two parallel mounted diffraction gratings for compensation of the normal fiber dispersion. The pump light is delivered by a 980 nm laser diode through a dichroic mirror and the polarization beam splitter at the isolator rejected one polarization and acted as the output port

Mode-locked femtosecond fiber lasers are suitable for a large variety of applications including metrology, nanostructuring and medical treatments [1]. Especially passively mode-locked ytterbium-doped fiber lasers are appropriate to match most of the required parameters in respect of output energy, pulse duration and signal bandwidth [2]. Furthermore, systems based on double-clad fibers offer additional advantages like high efficiency, reliability and low cost.