Influence of geometry passive Q-switch based on a nanopowder-polymer on the characteristics of an erbium ring fiber laser

• Published in: Optical fiber technology 2024-05, Vol.84, p.103751, Article 103751
• Main Authors: Sudas, D.P., Yakushcheva, G.G., Kuznetsov, P.I.
• Format: Article
• Language: English
• Subjects: Bi2Te3; Nanosheet; Optical fiber taper; Q-switch; Saturable absorber
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2024.103751

•The localization of gray losses during chemical etching has been determined.•A comparison is made of the effect of the type of Q-switch mode.•SA was created based on Bi2Te3 nanopowder - polymer.•The pulse duration in this case was 5 ns with a repetition rate of 4 MHz.•Taper-based Q-switch fiber laser has a pulse energy of more than 1000 nJ. The presented work shows an influence of geometry passive Q-switch based on a nanopowder-polymer on the characteristics of an erbium ring fiber laser. The saturable absorber Bi2Te3 was applied to two types of specially prepared samples of thinned sections of optical fiber, and the resulting structures were built into the ring circuit of an erbium fiber laser. In the first case, the surface of the light guide segment was thinned by chemical etching, and in the second, by mechanical grinding. For the first time, the time-domain optical reflectometry technique was used to control the quality of the resulting sample surface and the resulting losses. For a more complete comparison, a set of different optical splitters was used, providing a change in the feedback coefficient in the resonator from 5 to 95 %. A study in the mode of passive Q-switching using polarized light showed that for both types of modulators there are optimal ratios of the amount of energy output from the resonator to obtain the highest values of the average generation power. The d-shape fiber modulator allows mode-locking to be observed without any additional changes to the laser circuit. The pulse duration in this case was 5 ns with a repetition rate of 4 MHz. A Q-switch based on a chemically thinned fiber segment made it possible to obtain narrower pulses in Q-switching mode (up to 700 ns at 38 kHz), a stable peak position in the transmission spectrum, and an average power of 34 mW.