Excited-state absorption as a source of nonlinear thermo-induced lensing and self-Q-switching in an all-fiber Erbium laser

A modeling of an all-fiber self-Q-switched Erbium laser is developed, implying that the mechanism of self-Q-switching is the power-dependent thermo-induced lensing in Erbium fiber that stems from the excited-state absorption at the laser wavelength. Experimental dependencies of repetition rate (curve 1) and pulse duration (curve 2) of Erbium fiber laser at CW operation (left from dashed line) and self-Q-switching (right from dashed line) VS pump power (L = 155 cm).