40  µm core diameter ytterbium-doped VLMA fiber for high-peak-power nanosecond pulse amplification

In the context of microelectronic processing applications, the development of nanosecond infrared pulsed laser sources with high peak and average power is essential to support the ongoing effort to improve machining productivity. In this paper, we propose a master oscillator fiber power amplifier (MOFPA) featuring an innovative design of a polarization-maintaining (PM) very large mode area (VLMA) ytterbium-doped fiber amplifier. This fiber possesses a mode field diameter (MFD) of 38±2µm and demonstrates significant pump absorption, a combination of properties that effectively pushes back the onset of nonlinear effects in terms of peak power.