Optical modulation in Er-doped fiber laser delivering dark pulse utilizing side polished fiber coated with Ti3AlC2 as saturable absorber

Dark pulse mode-locked Erbium doped fiber laser (EDFL) was demonstrated in this work by employing side polished fiber (SPF) coated with Ti _3 AlC _2 solution using drop casting method. The modulation depth of fabricated SPF coated with Ti _3 AlC _2 solution was characterized at 2.2%. This SPF coated structure allowed the formation of dark mode-locked pulse with improved the birefringence and nonlinearity in EDFL. The dark pulse generated was cubic-quintic nonlinear Schrödinger equation (CQNLSE) dark pulse with center wavelength at 1558.935 nm, repetition rate 1.839 MHz and pulse width 170.2 ns. Pulse stability was examined, revealing a high signal to noise ratio (SNR) of 65.86 dB. This work could serve as a foundation for the development of sustainable industry, innovation and infrastructure.