Single- and dual-wavelength Q-switched EDFL based on MoAlB saturable absorber

A single- and dual-wavelength Q-switched erbium-doped fibre laser (EDFL) was experimentally demonstrated by employing a molybdenum aluminium boride (MoAlB) saturable absorber (SA). The MoAlB film was fabricated via a polyvinyl alcohol (PVA) embedding technique. By integrating the MoAlB-PVA SA into a ring-cavity EDFL, stable Q-switched pulses were achieved, delivering a minimum pulse duration of 6.45 µs and a maximum repetition rate of 50.25 kHz. Dual-wavelength operation was achieved at 1559.8 and 1560.7 nm by finely adjusting the cavity loss through rotation of the polarization controller. To the best of our knowledge, this is the first demonstration of dual-wavelength lasing in the 1.5 µm region utilizing a MoAlB-PVA SA. Moreover, single-wavelength Q-switched operation at 1558.3 nm was obtained. The findings demonstrated MoAlB as a promising candidate for compact, stable and wavelength-tunable fibre lasers, with potential applications in optical communications, sensing and photonic technologies.