报道了一种基于同一台光纤飞秒激光器的双路飞秒激光相干合成技术,获得脉宽只有4个光学周期(14 fs)的少周期飞秒脉冲。通过数值模拟证明了基于自频移孤子的相干合成为拓宽光谱、窄化脉冲提供了一个很好的方法,是获得少周期飞秒脉冲的可行方案。实验中,一台掺镱光纤飞秒放大系统输出脉宽为62 fs,中心波长为1040 nm的近变换极限脉冲,该脉冲分束后,一束作为基态孤子,另一束耦合到全固光子带隙光纤中产生自频移孤子,通过调整入射脉冲功率等参数获得了中心波长为1150 nm,脉宽为55 fs的近变换极限自频移孤子。将基态孤子与该自频移孤子相干合成,得到了脉宽仅4个光学周期(14 fs)的激光脉冲。 Reported a two-way femtosecond laser coherent integration technology based on the same optical fiber femtosecond laser and obtained a few-cycle femtosecond pulse with only 4 optical periods (14 fs). The numerical simulation shows that the coherent integration based on self-shifting soliton provides a good method for broadening the spectrum and narrowing the pulse. It is a feasible scheme to obtain the femtosecond pulse with less period. In the experiment, a ytterbium-doped fiber femtosecond amplification system outputs a near-transform limit pulse with a pulse width of 62 fs and a center wavelength of 1040 nm. After the pulse splitting, one beam acts as a ground state soliton and the other beam couples to an all-solid photon Self-shifting solitons are generated in the bandgap fiber. Near-extremal self-shifting solitons with a center wavelength of 1150 nm and a pulse width of 55 fs are obtained by adjusting the incident pulse power and other parameters. The ground state soliton is coherently synthesized with this self-shifting soliton, and a laser pulse with a pulse width of only 4 optical periods (14 fs) is obtained.