Femto/nano-second switchable passively mode-locked fiber laser with analytic modeling by cubic-quintic Ginzburg-Landau equation

TL;DR

This paper demonstrates a passively mode-locked erbium-doped fiber laser with switchable pulse widths from femtoseconds to nanoseconds, supported by an analytic model based on the cubic-quintic Ginzburg-Landau equation.

Contribution

It introduces a novel fiber laser with tunable pulse durations and provides an analytic model linking pulsewidths to cavity parameters.

Findings

Achieved pulsewidth switching from 473 fs to 76.8 ns.

Observed coexistence of femto- and nanosecond pulses in dual-width mode-locking.

Mode-locking behavior explained by gain balancing and intracavity effects.

Abstract

We report a passively mode-locked erbium-doped fiber laser with pulsewidths switchable from 473 fs to 76.8 ns, where the fundamental mode-locking, noise-like pulse, nanosecond mode-locking, and dual-width mode-locking are obtained by adjusting a polarization controller. Co-existence of femto- and nano-second pulses in dual-width mode-locking is attributed to the gain balancing. Analytic modeling of the fiber laser with cubic-quintic Ginzburg-Landau equation is presented, in which the pulsewidths are calculated as functions of dispersion, saturable absorption, and self-phase modulation. The generation of nanosecond pulses is attributed to weakened intracavity pulse-shortening strength and reduced effective self-phase modulation in the laser cavity.