Single-frequency gain-switched ytterbium-doped fiber laser at 1017 nm based on dynamic self-induced grating in a saturable absorber

We report on a stable single-frequency gain-switched ytterbium-doped fiber (YDF) laser at 1017 nm based on saturable absorber (SA) properties. The laser is realized by utilizing a short-length, high-concentration phosphosilicate YDF that simultaneously acts as an SA and a gain medium in a linear cavity. Despite the fact that gain switching is achieved by modulating the pump laser, single-frequency operation is sustained due to dynamic self-induced grating. By making use of high-concentration phosphosilicate YDF and selecting a suitable spectral region, grating is strongly induced along the cavity to stabilize single-mode operation. Additionally, the residual grating property in SA assures single-mode gain-switched performance at high repetition rates. Here, the laser generates pulses with 427 ns duration at 100 kHz, yielding the mean power of 12 mW with linewidth of less than 7.5 MHz. (C) 2018 Optical Society of America