Open Access5 kW Near-Diffraction-Limited and 8 kW High-Brightness Monolithic Continuous Wave Fiber Lasers Directly Pumped by Laser Diodes
Author(s) -
Qiang Fang,
Jinhui Li,
Wei Shi,
Yuguo Qin,
Yang Xu,
Xiangjie Meng,
Robert A. Norwood,
Nasser Peyghambarian
Publication year - 2017
Publication title -
ieee photonics journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 73
eISSN - 1943-0655
pISSN - 1943-0647
DOI - 10.1109/jphot.2017.2744803
Subject(s) - engineered materials, dielectrics and plasmas , photonics and electrooptics
Tandem pumping technique are traditionally adopted to develop >3-kW continuous-wave (cw) Yb3+-doped fiber lasers, which are usually pumped by other fiber lasers at shorter wavelengths (1018 nm e.g.,). Fiber lasers directly pumped by laser diodes have higher wall-plug efficiency and are more compact. Here we report two high brightness monolithic cw fiber laser sources at 1080 nm. Both lasers consist of a cw fiber laser oscillator and one laser-diode pumped double cladding fiber amplifier in the master oscillator-power amplifier configuration. One laser, using 30-μm-core Yb3+-doped fiber as the gain medium, can produce >5-kW average laser power with near diffraction-limited beam quality (M2<1.8). The slope efficiency of the fiber amplifier with respect to the launched pump power reached 86.5%. The other laser utilized 50-μm-core Yb3+-doped fiber as the gain medium and produced >8-kW average laser power with high beam quality (M2: ∼ 4). The slope efficiency of the fiber amplifier with respect to the launched pump power reach 83%. To the best of our knowledge, this is the first detailed report for >5-kW near-diffraction-limited and >8-kW high-brightness monolithic fiber lasers directly pumped by laser diodes.