Generation of high-power Q-switched pulses based on arc-shaped fiber and tapered fiber with Sb₂Te₃ in erbium/ytterbium doped fiber laser

This study illustrates the capability of antimony telluride (Sb₂Te₃) utilized as a saturable absorber (SA) for generating high-power Q-switching in the 1.5-µm region. First, the exfoliated Sb₂Te₃ solution was fabricated using the liquid phase exfoliation (LPE) technique and integrated onto a D-shaped and tapered fiber, respectively. Then, the SA was inserted into the erbium-ytterbium-doped fiber laser (EYDFL) cavity. For the arc-shaped fiber-based SA, the passive Q-switched pulses were obtained at 1.34 W threshold pump power, whereas the tapered fiber-based SA has a threshold of 0.4 W. As a result, the highest average Q-switched optical power generated by Sb₂Te₃-coated arc-shaped fiber was 140.2 mW with a repetition rate ranging from 35.7 to 91.3 kHz and pulse widths from 2.51 to 1.65 µs. On the other hand, the tapered fiber coated with Sb₂Te₃ could only generate a maximum average output power of 21.7 mW. Moreover, this SA generates Q-switched pulses with a repetition rate ranging from 5.76 kHz to 39.2 kHz and a pulse width from 5.14 to 16.34 µs. This indicates that Sb₂Te₃ can serve its purpose as an SA to produce high-power Q-switched pulses without degradation.