The effect of passive Q-switching observed in an erbium-doped fiber laser at a low pumping power

The effect of passive Q-switching was observed in an erbium fiber laser at a pumping power below 100 mW. The phenomenon is explained by a cascade process of the Rayleigh light scattering and the induced Mandelshtam-Brillouin scattering in a fiber resonator of the laser. In the Q-switched mode, the laser produced giant output pulses with a duration below 15 ns, a peak power up to 200 W, and a repetition period of 300-500 mus. The proposed Q-switching mechanism is inferred from the characteristic features of the laser pulse oscillograms measured at a similar to1 ns resolution. Previously, this effect was observed only in high-power fiber lasers at a pumping power of similar to2 W. (C) 2001 MAIK "Nauka/Interperiodica".