Self-induced laser line sweeping and self-pulsing in rare-earth doped fiber lasers

Abstract

We report laser line self-sweeping phenomenon in rare-earth doped fiber lasers. The effect of self-sweeping is observed in erbium-doped fiber laser and also in the ytterbium-doped one. The former, having linear layout, is core-pumped by laser diode (LD) at 980 nm. Laser cavity is formed with fiber loop mirror and angle cleaved fiber end. Laser operation is delimited by tunable filter; we observed sweeping regime in 0.5 nm wide interval defined by the filter. Yb-doped allfiber laser has linear layout as well. Laser is cladding-pumped by LD at about 976 nm; cavity is constrained by rightangle cleaved fibers. We observed laser line sweeping having a range of 6 – 8 nm. We characterized both lasers with respect to sweeping properties thoroughly. We present output laser line wavelength and instant output intensity versus time; we show dependence of sweeping range, sweeping rate, and sweeping period on output laser power and pump laser temperature (pump laser wavelength).