MnFe2O saturable absorber for nanosecond Q-switched fiber laser

Abstract

Abstract Low-dimensional (LD) materials show the extraordinary properties and have led to applications in the fields of photonics, optoelectronics and energy. As a kind of zero-dimensional (0D) transition metal oxides, MnFe2O4 nanoparticles possess various magneto-optical properties. However, the nonlinear optical characteristics as well as the applications in pulsed lasers have never been studied so far. Herein, the MnFe2O4 nanoparticles with diameter of 10\xa0nm were synthesized by the thermal decomposition method. The MnFe2O4-microfiber device was prepared by depositing MnFe2O4 nanoparticles on a microfiber, whose saturation intensity/modulation depth was measured to be 16.68\xa0MW/cm2/19.64%. Furthermore, this MnFe2O4-microfiber device was used to generate passively Q-switching laser pulses in Er-doped fiber (EDF) laser. Under the pump power of 80–780 mW, the pulse duration/repetition rate varies from 4.76\xa0μs/73.1\xa0kHz to 622\xa0ns/230.9\xa0kHz. The largest output power is 29.75 mW. The 70\xa0dB signal-to-noise ratio (SNR) verifies the stability of Q-switching operation. This work is the first demonstration of using MnFe2O4 nanoparticles as saturable absorber (SA) in designing Q-switching laser. Compared to recent reported Q-switching EDF lasers with LD materials, our work shows some improvements. These experimental results demonstrate that MnFe2O4 nanoparticles can be developed as an efficient SA materials and have potential photonics applications.