Passively Q-switched EDFL using Fe3O4-nanoparticle saturable absorber

TL;DR

This paper demonstrates a passively Q-switched erbium-doped fiber laser using a Fe3O4 nanoparticle-based saturable absorber, achieving stable pulsed operation with high nonlinear response and low threshold power.

Contribution

It introduces a novel Fe3O4 nanoparticle-based saturable absorber for Q-switching in EDFL, showing enhanced nonlinear optical properties and stable laser performance.

Findings

Maximum pulse energy of 23.76 nJ

Repetition rate of 33.3 kHz

Pulse width of 3.2 microseconds

Abstract

We experimentally demonstrate a passively Q-switched erbium-doped fiber laser (EDFL) operation by using a saturable absorber based on Fe3O4 nanoparticles (FONP) in magnetic fluid (MF). As a kind of transition metal oxide, the FONP has a large nonlinear optical response with a fast response time for saturable absorber. By depositing MF at the end of optical fiber ferrule, we fabricated a FONP-based saturable absorber, which enables a strong light-matter interaction owing to the confined transmitted optical field within the single mode fiber. Because of large third-order optical nonlinearities of FONP-based saturable absorber, large modulation depth of 8.2% and non saturable absorption of 56.6% are demonstrated. As a result, stable passively Q-switched EDFL pulses with maximum output pulse energy of 23.76 nJ, repetition rate of 33.3 kHz, and pulse width of 3.2 {\mu}s are achieved when the input pump power is 110 mW at the wavelength of 980 nm. The laser features a low threshold pump power of ~15 mW.