402 kW high pulse peak power and energy ultrafast fiber laser at 2-µm using MOPA system

Abstract

In this work, high-power mode-locked pulses with an average output power of 5 W have been generated using a nonlinear polarization rotation (NPR) technique operating in a master oscillator power amplifier (MOPA) system. The mode-locked laser oscillator operated in an anomalous dispersion regime, producing seed pulses with a center wavelength of 1946.35 nm, a 3-dB bandwidth of 4.2 nm, and a repetition rate of 16.7 MHz. The generated pulses demonstrated outstanding stability with a signal-to-noise ratio (SNR) of approximately 65 dB. Following amplification through the amplifier stages, these pulses exhibited excellent characteristics, including ultrashort pulse durations of 311 fs with a remarkable peak power of 402 kW and pulse energy of 125 nJ. This experimental demonstration represents a practical and robust platform for generating ultrashort, high peak power, and energy in the 2-µm region. The laser’s operating wavelength, high peak power, and ultrashort pulse duration make this source promising for medical surgery applications. Some potential uses include precise tissue ablation with minimal thermal damage, enabling advanced procedures in areas like soft and hard tissue surgeries.