The high degree of freedom and novel nonlinear phenomena of multimode fiber are attracting attention. In this work,we demonstrate a spatiotemporal mode-locked multimode fiber laser, which relies on microfiber knot res...The high degree of freedom and novel nonlinear phenomena of multimode fiber are attracting attention. In this work,we demonstrate a spatiotemporal mode-locked multimode fiber laser, which relies on microfiber knot resonance(MKR) via dissipative four-wave-mixing(DFMW) to achieve high-repetition-rate pulses. Apart from that, DFMW mode locking with switchable central wavelengths can also be obtained. It was further found that high pulse energy induced nonlinear effect of the dominant mode-locking mechanism transforming from DFMW to nonlinear Kerr beam cleaning effect(NL-KBC). The experimental results are valuable for further comprehending the dynamic characteristics of spatiotemporal mode-locked multimode fiber lasers, facilitating them much more accessible for applications.展开更多
We report Q-switched mode-locked(QML)pulses generation in an Yb-doped multimode fiber(MMF)laser by using a graphene-deposited multimode microfiber(GMM)for the first time,to the best of our knowledge.The single-wavelen...We report Q-switched mode-locked(QML)pulses generation in an Yb-doped multimode fiber(MMF)laser by using a graphene-deposited multimode microfiber(GMM)for the first time,to the best of our knowledge.The single-wavelength QML operation with the central wavelength tunable from 1028.81 nm to 1039.20 nm and the dual-wavelength QML operation with the wavelength spacing tunable from 0.93 nm to 5.79 nm are achieved due to the multimode interference filtering effect induced by the few-mode fiber and MMF structure and the GMM in the cavity.Particularly,in the single-wavelength QML operation,the fifth harmonic is also realized owing to the high nonlinear effect of the GMM.The obtained results indicate that the QML pulses can be generated in the MMF laser,and such a flexible tunable laser has promising applications in optical sensing,measuring,and laser processing.展开更多
We propose and demonstrate a scheme to smooth and shape the on-target patterns in multimode fiber lasers, which includes expanding-collimating system and lens array （LA）. A smooth pattern with flat-top and sharp-edg...We propose and demonstrate a scheme to smooth and shape the on-target patterns in multimode fiber lasers, which includes expanding-collimating system and lens array （LA）. A smooth pattern with flat-top and sharp-edge profiles can be obtained with the irradiation nonuniformity decreasing significantly. We analyze the effects of the parameters such as defocus distance, the tilt angles, the number of the incident fiber lasers, and the diffraction-weakened LA on the uniformity irradiation of target by numerical simulations.展开更多
基金Project partially supported by the National Natural Science Foundation of China (Grant Nos. 91950105 and 62175116)the 1311 Talent Plan of Nanjing University of Posts and Telecommunications。
文摘The high degree of freedom and novel nonlinear phenomena of multimode fiber are attracting attention. In this work,we demonstrate a spatiotemporal mode-locked multimode fiber laser, which relies on microfiber knot resonance(MKR) via dissipative four-wave-mixing(DFMW) to achieve high-repetition-rate pulses. Apart from that, DFMW mode locking with switchable central wavelengths can also be obtained. It was further found that high pulse energy induced nonlinear effect of the dominant mode-locking mechanism transforming from DFMW to nonlinear Kerr beam cleaning effect(NL-KBC). The experimental results are valuable for further comprehending the dynamic characteristics of spatiotemporal mode-locked multimode fiber lasers, facilitating them much more accessible for applications.
基金supported by the National Natural Science Foundation of China(Nos.92050101,61875058,11874018,11974006,and 61378036)the Natural Science Foundation of Guangdong Province(No.2021A1515011608)。
文摘We report Q-switched mode-locked(QML)pulses generation in an Yb-doped multimode fiber(MMF)laser by using a graphene-deposited multimode microfiber(GMM)for the first time,to the best of our knowledge.The single-wavelength QML operation with the central wavelength tunable from 1028.81 nm to 1039.20 nm and the dual-wavelength QML operation with the wavelength spacing tunable from 0.93 nm to 5.79 nm are achieved due to the multimode interference filtering effect induced by the few-mode fiber and MMF structure and the GMM in the cavity.Particularly,in the single-wavelength QML operation,the fifth harmonic is also realized owing to the high nonlinear effect of the GMM.The obtained results indicate that the QML pulses can be generated in the MMF laser,and such a flexible tunable laser has promising applications in optical sensing,measuring,and laser processing.
基金supported by the National Natural Science Foundation of China under Grant No.11374285
文摘We propose and demonstrate a scheme to smooth and shape the on-target patterns in multimode fiber lasers, which includes expanding-collimating system and lens array （LA）. A smooth pattern with flat-top and sharp-edge profiles can be obtained with the irradiation nonuniformity decreasing significantly. We analyze the effects of the parameters such as defocus distance, the tilt angles, the number of the incident fiber lasers, and the diffraction-weakened LA on the uniformity irradiation of target by numerical simulations.
