Passively mode-locked C-band fiber laser employing carbon nanotubes as saturable absorbers

Passively mode-locked fiber lasers find extensive applications in communications, ultrafast science, and materials processing. In this study, carbon nanotubes (CNTs) were employed as saturable absorbers in a passively mode-locked fiber laser. We systematically explored the influence of different dispersion characteristics on the output of mode-locked pulses by precisely adjusting the cavity length. The experimental results clearly indicate that when the dispersion is altered from −0.25 to −0.12 ps2, the pulse width can be effectively reduced from 858 to 645 fs. In addition, we comparatively analyzed the effects of CNT-SA aqueous solution and CNT-PVA-SA on the pulse output of the fiber laser. It was discovered that the morphology of the material exerts a significant impact on the mode-locking threshold, pulse width, and stability of the laser. This discovery offers a crucial theoretical foundation for future material selection in the field of passively mode-locked fiber lasers, facilitating more optimized designs and enhanced performance in related applications.