Generation mode-locked square-wave pulse based on reverse saturable absorption effect in graded index multimode fiber

TL;DR

This paper demonstrates a novel mode-locked square-wave pulse generation in a Yb-doped graded index multimode fiber laser utilizing reverse saturable absorption, with tunable pulse widths and high mode stability.

Contribution

It introduces the first demonstration of mode-locked square-wave pulses in this fiber laser configuration based on reverse saturable absorption effects.

Findings

Pulse width tunable from 350 ps to 52.6 ns

Supermode suppression ratio exceeds 65 dB

Spectrum bandwidth of 0.73 nm

Abstract

We firstly report mode-locked square-wave pulse in Yb-doped fiber laser based on graded index multimode fiber of reverse suturable absorption. By adjusting the pump power, the width of the square-wave can be tuned range from 350 ps to 52.6 ns with 3dB bandwidth spectrum of 0.73 nm. The supermode suppression ratio exceeds ~ 65 dB, which indicates excellent mode-locked operation state, and we also study the characteristic of pulse by the chirp measurement system. The mode-locked square-wave pulse fiber laser can sever as high power light source for industrial applications.