实验探究了基于被动全光同步的中红外差频产生技术,采用主-从注入锁定实现了全保偏掺镱和掺铒锁模光纤激光器的同步脉冲输出,并经过级联光纤放大在PPLN晶体中获得了中心波长为3071 nm的中红外皮秒脉冲,最大泵浦光转换效率为68.3%,峰值平均功率达1.36 W。研究发现,所使用的同步脉冲诱导差频技术能够显著降低中红外产生的泵浦阈值。此外,得益于脉冲产生、同步与放大全链路的保偏光纤架构,中红外超快光源表现出良好的长期稳定性,平均功率的相对抖动低至0.2%。

We have experimentally investigated mid-infrared (MIR) difference-frequency generation (DFG) based on passive all-optical synchronization. Synchronized pulses were obtained by master-slave injection locking between all-polarization-maintaining Yb- and Er-doped fiber lasers, which were amplified by cascaded fiber amplifiers to realize MIR picosecond pulses at 3071 nm within a PPLN crystal. The maximum pump conversion efficiency is 68.3%, and the peak average power reaches 1.36 W. The results show that the synchronous pulse induced DFG can substantially reduce the pump threshold. Additionally, benefiting from the all-polarization-maintaining fiber architecture for the pulse generation, synchronization and amplification, the MIR ultrafast light source exhibits excellent long-term stability with a relative fluctuation of average power as low as 0.2%.