Excessively tilted fiber grating based Fe3O4 saturable absorber for passively mode-locked fiber laser.

Hushan Wang,Wei Zhao,Ting Zhang,Kaiming Zhou,Chuandong Sun,Fengyan Zhao,Wei Zhang,Xiaohong Hu,Lin Zhang,Zhijun Yan,Yishan Wang

doi:10.1364/oe.27.015693

Abstract

A novel approach to saturable absorber (SA) formation is presented by taking advantage of the mode coupling property of excessively tilted fiber grating (Ex-TFG). Stable mode-locked operation can be conveniently achieved based on the interaction between Ex-TFG coupled light and deposited ferroferric-oxide (Fe3O4) nanoparticles. The central wavelength, bandwidth and single pulse duration of the output are 1595 nm, 4.05 nm, and 912 fs, respectively. The fiber laser exhibits good long-term stability with signal-to-noise ratio (SNR) of 67 dB. For the first time, to the best of our knowledge, Ex-TFG based Fe3O4 SA for mode-locked fiber laser is demonstrated.

Highlights

Stable ultrashort pulse fiber lasers are of great importance for many fields in science and engineering, such as optical communication, laser material processing and biomedical optics
For the sake of enhancing power resistance, these SAs have evolved from traditional semiconductor saturable absorber mirrors (SESAMs) [3] to one-dimensional and twodimensional materials, such as carbon nanotubes [4,5,6], graphene [7,8,9,10,11], black phosphorous [12,13,14,15], and transition-metal dichalcogenides (TMDs) [16,17,18,19,20]
The fiber laser is composed of 2.8 m erbium-doped fiber (EDF) (Nufern SM-ESF-7/125) with an absorption coefficient of 55 dB/m at 1530 nm, a polarization independent isolator (PI-ISO), Fe3O4 nanoparticles coated excessively tilted fiber grating (Ex-TFG) as SA, two polarization controllers (PCs) and an optical coupler (OC) with an output ratio of 10%

Summary

Introduction

Stable ultrashort pulse fiber lasers are of great importance for many fields in science and engineering, such as optical communication, laser material processing and biomedical optics. Nonlinear optical response characteristic of Fe3O4 nanoparticles and realized a passively Qswitching operation in erbium-doped fiber laser [25]. For the moment, there are still no reports on stable mode-locked operation in fiber lasers by using the Fe3O4 based SA.

Results

Conclusion