Indium antimonide-based saturable absorber to demonstrate passively Q-switched and mode-locked operation

Abstract

In this work, an Indium Antimonide-polyvinyl alcohol (InSb-PVA) film was fabricated, and its nonlinear characteristics were researched. The modulation depth intensity and saturation intensity were 13.61% and 2.02 MW/cm 2 , correspondingly. Based on InSb as a saturable absorber (SA), an erbium-doped fiber laser (EDFL) with passively Qswitched and mode-locked operation was generated. The Q-switched operation was achieved with a maxinum pulse energy of 45.8 nJ and a minimum pulse duration of 4.3 μs. As the pump power rises, the repetition rate rises from 7.6 kHz to 25.05 kHz and the pulse duration falls from 20.1 μs to 4.3 μs. By adjusting the length of the single-mode fiber to manage the dispersion, a stable mode-locked EDFL with a maximum average output power of 8.03 mW and a central wavelength of 1566.54 nm was obtained. The experimental results fully demonstrated that InSb has remarkable nonlinear absorption performance and enormous potential for ultra-fast photonics devices.