Q-switched and mode-locked erbium doped pulsed fiber laser using Molybdenum Titanium Aluminum Carbide as saturable absorber

• المؤلف الرئيسي: Zaini, Muhammad Aizat Zaim
• التنسيق: أطروحة
• اللغة: الإنجليزية; الإنجليزية
• منشور في: 2025
• الموضوعات: T Technology; TK Electrical engineering. Electronics Nuclear engineering
• الوصول للمادة أونلاين: http://eprints.utem.edu.my/id/eprint/29351/

This research focuses on the main limitations in existing saturable absorber (SA) materials, specifically their low optical damage thresholds, complex fabrication processes, and limited compatibility with high-power and flexible fiber laser configurations. To overcome these challenges, the study investigates Molybdenum Titanium Aluminum Carbide (Mo2TiAlC2), a MAX phase material as a saturable absorber for pulsed fiber laser applications. A Mo2TiAlC2-PVA thin film was fabricated using the solvent casting method and characterized using Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDX) to confirm its structural and elemental properties. Optical measurements revealed a modulation depth of 2.8 % and a saturable intensity of 0.2 kW/cm2, indicating its suitability for nonlinear photonic applications. The thin film was integrated into an erbium-doped fiber laser (EDFL) to demonstrate both Q-switched and mode-locked operations. In Q-switched operation, the laser achieved repetition rates from 31.1 kHz to 66.83 kHz, with pulse widths ranging from 13.45 µs to 6.35 µs as pump power increased. The maximum output power and pulse energy were 6.56 mW and 98.16 nJ, respectively, with a signal-to-noise ratio (SNR) of 58 dB. For mode-locking, the cavity was integrated with 150 m and 200 m of single-mode fiber (SMF) to study dispersion effects. The 150 m SMF setup achieved a repetition rate of 1.257 MHz with a pulse width of 357 ns, while the 200 m of SMF generated 0.9524 MHz and 493.2 ns, respectively. Both configurations maintained stable mode-locking, with output powers above 11 mW and pulse energies up to 11.55 nJ. These outcomes validate the effectiveness of Mo2TiAlC2 as a saturable absorber, combining strong nonlinear response with thermal stability and simple fabrication. The study concludes that Mo2TiAlC2-PVA thin films are a practical and high-performing alternative to conventional SA materials for ultrafast fiber laser systems.