Silver indium selenide composite as a saturable absorber for passive Q-switched and mode-locked pulsed generation in erbium-doped fiber laser

Abstract

We have successfully accomplished a Q-switched and mode-locked pulse in an Erbium-doped fiber (EDF) laser cavity by integrating a new composite material silver doped Indium Selenide (Ag/In2Se3)-based saturable absorber (SA). Ag/In2Se3 film was synthesized by using pulsed laser ablation and a common dry cast method to form a free-standing thin film SA. This SA device exhibits a nonlinear optical property of modulation depth, saturable intensity, and non-saturable loss of 2.27%, 847.20 MW/cm2, and 16.82% respectively. By implementing Ag/In2Se3 film into the EDF laser cavity, a Q-switched pulsed began to generate at a threshold pump power of 27.63 mW. Then as 100 m single-mode fiber (SMF) was implemented into the EDF laser cavity, a traditional soliton pulse began to appear with 1.873 MHz, at the threshold pump power of 76.63 mW with a narrow pulse width of 3.11 ps, and remarkable temporal stability, as demonstrated by a signal noise ratio (SNR) of 79.62 dB. The peak power of 2.61 kW was recorded. This contribution further verifies the improved optical qualities of the Ag/In2Se3 composite and offers a new possibility for developing broadband SA devices for various photonics applications.