We report on a nanosecond all-fiber amplifier with repetition rate of tens of MHz. It is based on a passively mode-locked fiber oscillator at 1064 nm, which has a pulse width of 28 ps and repetition rate of 27.7 MHz. The single-mode fiber with length of 8 km is adopted as a fiber stretcher, in which new frequency components are introduced by strong nonlinear effect such as self-phase modulation, resulting in the broadening of spectral bandwidth from 0.4 nm to around 20 nm. The group-velocity dispersion of the 8 km fiber stretcher is −38 ps (nm km) ⁻¹, which stretches the pulse duration of the picosecond pulse to 1–7 ns. At the repetition rate of 27.7 MHz, an average power of 54 W is demonstrated with pulse width of 1.3 ns, and 21 W is achieved with pulse width of ∼5 ns, which have optical-to-optical conversion efficiencies of 41.2% and 30.1% respectively. This all-fiber amplifier based on the passively mode-locked fiber oscillator and 8 km single-mode fiber stretcher is capable of delivering nanosecond pulses while maintaining an ultra-high repetition rate of tens of MHz.

我们报告了一个具有数十MHz重复频率的纳秒级全光纤放大器。它基于1064 nm的无源锁模光纤振荡器，其脉冲宽度为28 ps，重复频率为27.7 MHz。采用长度为8 km的单模光纤作为光纤扩展器，其中通过强大的非线性效应（例如自相位调制）引入了新的频率分量，从而将光谱带宽从0.4 nm扩展到了约20 nm。8 km光纤延伸器的群速度色散为-38 ps（nm km）^-1，这会将皮秒脉冲的脉冲持续时间延长到1-7 ns。在27.7 MHz的重复频率下，脉冲宽度为1.3 ns时，平均功率为54 W，脉冲宽度为〜5 ns时，平均功率为21 W，其光光转换效率为41.2％和30.1。 ％ 分别。这款基于无源锁模光纤振荡器和8 km单模光纤扩展器的全光纤放大器能够提供纳秒级脉冲，同时保持数十MHz的超高重复率。