Effect of pump wavelength on self-induced laser line sweeping in Yb-doped fiber laser

We have characterized ytterbium–doped fiber laser and described in detail the effect of pump wavelength on self–induced laser line sweeping (SLLS). SLLS is a transient laser regime manifested by a relatively slow laser line shifting and usually observed in the near of pump laser threshold. The fiber laser under consideration is cladding–pumped by a temperature stabilized multimode laser diode (LD) at about 976 nm. The output wavelength of the diode is tunable by changing the diode temperature and current through the diode. The cavity of the laser is formed by perpendicularly cleaved fiber ends. Using this laser layout we made detailed study of sweeping dependences on pump wavelength by adjustment of the LD current and LD case temperature. The laser manifested laser line sweeping within the range of 5–7 nm on a wide span of pump laser diode power and temperature: 15–45°C LD temperature scale and pump range reaching to more than twice the amount of excess over threshold. We performed the measurement of the laser line sweeping span, period and rate as the dependence of pump wavelength.