Self-pulsing in a double-clad ytterbium fiber laser induced by high scattering loss

The characteristics of self-pulsing behavior in a double-clad ytterbium-doped fiber laser are presented. The self-pulsing generates a supercontinuum spectrum that mostly propagates through the multimode structure of the fiber. In fact, 90% of the total power, including the fundamental laser wavelength and the generated supercontinuum spectrum, propagates trough the first cladding. The experimental evidence indicates that the main mechanism for the self-pulsing is the high scattering loss in the double-clad fiber.