Monolithic fiber laser oscillator with record high power. (1st June 2018)

• Record Type: Journal Article
• Authors: Yang, Baolai; Shi, Chen; Zhang, Hanwei; Ye, Qing; Pi, Haoyang; Tao, Rumao; Wang, Xiaolin; Ma, Pengfei; Leng, Jinyong; Chen, Zilun; Zhou, Pu; Xu, Xiaojun; Chen, Jinbao; Liu, Zejin
• Is Part Of: Laser physics letters. Volume 15:Number 7(2018:Jul.)
• Publication Date: 2018-06-01
• Subjects: fiber laser oscillator -- ytterbium-doped fiber laser -- transverse mode instability -- stimulated Raman scattering; Lasers -- Periodicals; Physics -- Periodicals; 621.366
• DOI: 10.1088/1612-202X/aac19f
• Languages: English
• ISSNs: 1612-2011

Abstract

Abstract: With an increasing output power, the power scaling of monolithic fiber laser oscillators faces the severe limitations of stimulated Raman scattering (SRS) and the transverse mode instability (TMI) effect. In this work, we report a high power monolithic fiber laser oscillator with a maximum output power of 5.2 kW, which is realized with a trade-off design between the SRS and TMI. The monolithic fiber laser oscillator is constructed with ytterbium-doped fiber with a core/inner cladding diameter of 25/400 µ m and corresponding home-made FBG. High-power 915 nm laser diodes are employed as a pump source and are distributed in a bidirectional-pump configuration. By optimizing the bidirectional pump proportion, the monolithic fiber laser oscillator is scaled up to 5.2 kW with a slope efficiency of ~63%. Operating at 5.2 kW, the intensity of the Raman stokes light is ~22 dB below the signal laser and the beam quality (M 2 -factor) is ~2.2. To the best of our knowledge, this is a record high power for monolithic fiber laser oscillators.