8-Hydroxyquinolino cadmium chloride hydrate for generating nanosecond and picosecond pulses in erbium-doped fiber laser cavity

•8-Hydroxyquinolino cadmium chloride hydrate (8-HQCdCl2H2O) as saturable absorber.•It has a modulation depth of 18%.•The Q-switched pulses have a duration of 726 ns and repetition rate of 150 kHz.•The mode-locked pulses have a pulse width of 1.83 ps and repetition rate of 1 MHz. In this paper, we experimentally proposed and demonstrated the application of thin-film saturable absorber (SA) based on 8-Hydroxyquinolino cadmium chloride hydrate (8-HQCdCl2H2O) material as both Q-switcher and mode-locker in the cavity of erbium-doped fiber laser (EDFL). The 8-HQCdCl2H2O was embedded in polyvinyl alcohol (PVA) to fabricate the thin-film, which has then employed in the Q-switched and mode-locked EDFL cavity for passively generating nanosecond and picosecond pulses, respectively. At the maximum pump power of 167 mW, the Q-switched laser-produced pulse train with a pulse width of 726 ns, a repetition rate of 150 kHz, and a signal-to-noise ratio (SNR) of 72 dB. We also demonstrated the generation of mode-locked picosecond pulses by adding 200 m long single-mode fiber (SMF) into the ring EDFL cavity. The mode-locked laser-generated pulses have a pulse width of 1.83 ps, a repetition rate of 1 MHz, and the SNR of 77 dB for the electrical spectrum.