All fiber ultrafast laser generating gigahertz pulse based on a hybrid plasmonic microfiber resonator

TL;DR

This paper presents a novel all-fiber ultrafast laser using a hybrid plasmonic microfiber resonator that achieves gigahertz pulse repetition rates by leveraging nonlinear polarization rotation to enhance dissipative four-wave-mixing mode-locking.

Contribution

It introduces a simple, versatile microfiber resonator device that combines polarization control, filtering, and nonlinear effects to generate high-repetition-rate ultrafast pulses.

Findings

Achieved stable pulsed laser operation at tens to hundreds of gigahertz.

Demonstrated the device's multifunctionality as a polarizer, filter, and nonlinear component.

Showed potential for low-cost, practical ultrafast light sources.

Abstract

Ultrafast lasers generating high repetition rate ultrashort pulses through various mode-locking methods can benefit many important applications including communication, materials processing, astronomical observation, etc. For decades, mode-locking based on dissipative four-wave-mixing (DFWM) has been fundamental in producing pulses with repetition rates on the order of gigahertz (GHz), where multiwavelength comb filters and long nonlinear components are elemental. Recently, this method has been improved using filter-driven DFWM, which exploits both the filtering and nonlinear features of silica microring resonators. However, the fabrication complexity and coupling loss between waveguides and fibers are problematics. In this study, we demonstrate a tens to hundreds of gigahertz stable pulsed all-fiber laser based on the hybrid plasmonic microfiber knot resonator device. Unlike previously reported pulse generation mechanisms, the operation utilizes the nonlinear-polarization-rotation (NPR) effect introduced by the polarization-dependent feature of the device to increase intracavity power for boosting DFWM mode-locking, which we term NPR -stimulated DFWM. The easily-fabricated versatile device acts as a polarizer, comb filter, and nonlinear component simultaneously, thereby introducing a novel application of microfiber resonator devices in ultrafast and nonlinear photonics. We believe that our work underpins a significant improvement in achieving practical low-cost ultrafast light sources.