Polarization Domain Formation and Domain Dynamics in a Quasi-Isotropic Cavity Fiber Laser

Polarization resolved study on the operation of a quasi-isotropic cavity erbium-doped fiber laser revealed a novel form of periodic fast polarization switching between the two orthogonal linearly polarized eigen-modes of the laser. We show both experimentally and theoretically that the operation of the laser is a result of the polarization domain formation, an effect in analog to the magnetic domain formation in ferromagnetic materials. Features of the polarization domains have been experimentally studied and compared with results of theoretical simulations. It is shown that the polarization domain formation is a general feature of the quasi-isotropic cavity fiber lasers, which could be exploited for controllable ultrafast polarization switching light sources for many photonic applications.