Mid-infrared dual-wavelength power regulation and linewidth narrowing using an F-P etalon in a multi-optical parametric oscillator based on MgO: APLN

•The narrow linewidth MOPO based on MgO: APLN by adding an F-P etalon is proposed.•For adding an F-P etalon, the linewidth of 3.30 μm and 3.84 μm is narrowed.•By changing the tilt angle of the F-P etalon, the output power differential is reduced.•Using an F-P etalon in MOPO can regulation the output power and narrow linewidth. The multi-optical parametric oscillator based on MgO: APLN has the problems of unbalanced gain and wide linewidth. Because the F-P etalon can not only narrow the linewidth, but also adjust the transmittance of different wavelengths. The narrow linewidth multi-optical parametric oscillator based on MgO: APLN by using an F-P etalon in the cavity is proposed. For adding an F-P etalon, the linewidth of 3.30 μm and 3.84 μm is narrowed from 2.98 nm and 3.15 nm to 0.81 nm and 1.07 nm. By changing the tilt angle of the F-P etalon, the output power differential between 3.84 µm and 3.30 µm is reduced from 1.325 W to 0.226 W. When the tilt angle is 1.84°, the balanced output power with 1.326 W at 3.30 µm and 1.552 W at 3.84 µm is achieved. The corresponding conversion efficiency is 3.02% and 3.54%, and the pulse width is 12.4 ns and 11.8 ns, respectively. The experimental result shows that power regulation and linewidth narrowing can be realized by using an F-P etalon.