High-Power Yb-Doped and All Fiber-Based Nanosecond MOPA Laser

Abstract

We report the results obtained by using a newly designed 300-µm-core-diameter Yb-doped fiber with a large cladding absorption of 23 dB/m at 976 nm. An average power of 512 W, a maximum pulse energy of 51.2 mJ laser is realized using the 300-µm-core Yb-doped fiber in the main amplifier with a slope efficiency of 72%. The entire laser system adopts an all-fiber construction with pulse control system. These results extend average power and peak power of nanosecond all fiber-based laser, exceeding to the 500 W and 1 MW regime simultaneously for the first time to the best of our knowledge.

15 mJ and high-peak-power nanosecond pulse based on all-fiber MOPA system

“…In additional, the self-phase modulate (SPM) significantly contributed to spectrum broadening [2,25]. Analogous scenarios were encountered in Fig.…”

“…The QBH is coated with a 1064 nm anti-reflection film to diminish output laser reflections and ensure stable, prolonged high-power laser output. The mode field adaptor (MFA) minimizes the welding mode loss and sustains suitable beam quality [2]. The cladding mode stripper (CMS) is employed to eliminate residual pumping laser.…”

“…The increasing allure of high-power fiber lasers and high pulse energies has garnered substantial attention due to elevated pulse peak power, robustness, effective heat dissipation, and heightened efficiency [1][2][3][4]. In recent years, the pursuit of laser systems combining high-average power and pulse energy has led to studies involving larger core diameter fibers in the main amplifier stage.…”

“…In recent years, the pursuit of laser systems combining high-average power and pulse energy has led to studies involving larger core diameter fibers in the main amplifier stage. However, nonlinear effects, particularly Stimulated Raman Scattering (SRS), continue to impact fiber laser output, especially in industrial high-pulsed lasers [2,5,6]. The SRS effect causes nonlinear wavelength shifting when signal power exceeds the SRS threshold [7][8][9].…”

“…Another approach involving a 50 μm Yb-doped multimode core and 62.5 μm multimode delivery fiber achieved 500 ns pulse width, 10 mJ pulse energy, and 256 W average power [19]. Employing a 300 μm LMA Yb-doped fiber in the main amplifier yielded an average power of 512 W, 51.2 mJ pulse energy, and 72% slope efficiency [2]. For further laser power improvements, multistage amplifiers [20], large-pitch photonic crystal fibers (LPFs) [10], beam combining by more laser modules [6] was investigated, resulting in 36 mJ at 10-ns pulse width, 26mJ at 60-ns pulse width, and 50 mJ at 150-ns pulse width, respectively.…”