Mid-infrared enhanced Raman soliton generation in an erbium-doped ZBLAN with record energy and peak power

The advancement of tunable ultrafast sources in the mid-infrared spectrum would bring about significant progress in various scientific fields. This study suggests a gain-modulation technique to increase the peak power and pulse energy of mid-infrared tunable Raman solitons. By utilizing a high-power 2-2.23 µm Raman soliton pulse as a pump source, mid-infrared Raman solitons within the 2-3.2 µm tuning range can be generated in a segment of Er 3+ : ZBLAN fiber. Additionally, the introduction of 976 nm pump light into the Er 3+ : ZBLAN fiber leverages the gain of Er 3+ to amplify the frequency shift velocity and pulse energy of the Raman soliton. Consequently, the frequency shift range of the Raman soliton is extended to 3.5 µm, with peak power and pulse energy reaching 0.93 MW and 107 nJ, respectively. These achievements represent the highest peak power and energy levels of Raman solitons generated in mid-infrared fibers to date.