Mode-locked laser with flat-top beam output based on all polarization-maintaining fiber structure

• Published in: Optics and laser technology 2022-12, Vol.156, p.108496, Article 108496
• Main Authors: Ma, Xuexiao, Dai, Chuansheng, Lv, Jialiang, Lin, Jiaqiang, Yao, Peijun, Xu, Lixin
• Format: Article
• Language: English
• Subjects: Beam synthesis; Flat-top beam; Mode-locked pulse
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2022.108496

•A mode-locked flat-top beam laser is demonstrated experimentally.•All-polarization-maintaining fiber structure is adopted.•The flat-top beam has good flatness.•The flat-top beam is obtained by the superposition of CVB and LP01 beam. By reason of the special intensity profile, the flat-top beam is applied in numerous fields. Utilizing fiber laser to generate the flat-top beam with excellent beam quality is gradually becoming a hot research topic in recent years. In this work, we propose a novel fiber laser that emits mode-locked pulse flat-top beam by the incoherent superposition of cylindrical vector modes (TM01) and fundamental modes (LP01). The beam obtained in our laser has a normalized root mean square (NRMS) of 0.127 and a steep degree Ω of 0.87 meaning the favorable effect of the experiment result. As far as we know, this laser is the first mode-locked pulse flat-top beam laser based on all polarization-maintaining fiber structure.