基于量子点可饱和吸收镜的锁模激光器

Mode-Locked Laser Based on Quantum Dot Saturable Absorption Mirror

锁模光纤激光器在工业加工、光通信、光学传感等领域有广泛的应用。由于在GaAs基板上制备的InAs量子点(QD)半导体可饱和吸收镜(QD-SESAM)增益谱较宽、成本较低,将其应用于锁模光纤激光器具有非常大的潜力。然而,生长发光中心波长(λ)为1550 nm的高性能QD-SESAM仍然十分困难。采用分子束外延(MBE)生长制备了1550 nm GaAs基InAs QD-SESAM,通过在SESAM上表面生长厚度为λ/4的SiO_(2)层,将QD-SESAM的调制深度提升至1.4%。使用这种新型的QD-SESAM优化了耦合效率,成功地构建了稳定的环形腔被动锁模掺铒光纤激光器,其斜率效率为2.2%,脉冲宽度为2 ps,重复频率为16.5 MHz,最大输出功率约为4.1 mW。结果表明,这种带有λ/4厚度SiO_(2)层的QD-SESAM在制备高性能锁模激光器方面具有非常大的应用潜力。

Mode-locked fiber lasers have been widely used in industrial processing,optical communication,optical sensing and other fields.The quantum dot semiconductor saturable absorption mirror(QD-SESAM)based on InAs/GaAs quantum dots(QDs)exhibits great potential for application in the mode-locked fiber laser due to its wide gain spectrum and low cost.However,it is still difficult to obtain the high-quality QD-SESAM with a central wavelength(λ)of 1550 nm.The InAs/GaAs QD-SESAM was prepared by molecular beam epitaxy(MBE)growth,and then,the SiO_(2) layer with a thickness ofλ/4 was grown on the surface of the SESAM,which increased the modulation depth of the QD-SESAM up to 1.4%.Based on the new QD-SESAM,a stable ring-cavity passively mode-locked erbium-doped fiber laser was successfully constructed by optimizing the couple efficiency and exhibits a slope efficiency of 2.2%,a pulse width of 2 ps,a repetition frequency of 16.5 MHz,and a maximum output power of about 4.1 mW.These results indicate that the QD-SESAM with a SiO_(2) layer ofλ/4 thickness has great application potential for fabricating mode-locked lasers with excellent performance.