Q-switched ytterbium-doped fiber laser via a thulium-doped fiber saturable absorber.

Abstract

We demonstrated a reliable and stable Q-switched ytterbium-doped fiber laser centered at 1069nm by employing a segment of 11cm thulium-doped fiber (TDF) as a saturable absorber (SA) in the ring cavity. The fiber SA has an optical absorption of 1.35dB at the Q-switched operating regime. As we increased the pump power from 109mW to the maximum available pump power of 206mW, a consistent Q-switched laser with output power ranging from 1.8 to 4.8mW was attained. The pulse width narrowed from 4.9 to 2.87μs, whereas the repetition rate increased from 40 to 60.2kHz. In addition, maximum pulse energy of 80.7nJ and a maximum peak power of 28.1mW were obtained at the maximum pump power. The signal to noise ratio (SNR) was around 47dB. Our experimental study shows that a segment of TDF can be used as a Q-switcher in the 1μm fiber laser cavity to facilitate a reliable and robust microsecond pulse generation.