Experimental-calculated estimation of fiber laser's response to pulsed X-rays

Experiments have been carried out to study the transient radiation-induced absorption in the active core of a double-clad ytterbium fiber and the response of a laser based on it under the exposure of pulsed X-rays. It has been found that the time of loss of laser performance (downtime) under pulsed irradiation increases with an increase in the absorbed of radiation and a decrease in the laser pump power and reaches values of $\sim$1 ms. An analysis of the experimental results shows that the laser response to the X-rays pulse exposure is determined by radiation-induced losses in the active fiber core. An experimental-calculated method for estimating the radiation reaction of a laser, based on the results of studies of the active fiber, is proposed.