H. Ahmad, N.A.M. Rusni, M.Z. Samion, S. Sagadevan
In this work, a TiO2/Ti3C2TX MXene composite saturable absorber (SA) in a thulium-holmium-doped fiber laser (THDFL) is used to generate harmonic mode-locked (HML) pulses. The SA demonstrated a modulation depth of 6.4%. The center wavelength of the fundamental HML pulses is 1904nm, with a repetition rate of 14.3MHz. The fundamental HML pulses exhibit excellent stability over long-term operation, with a high signal-to-noise ratio of 71dB after 4h. The laser cavity achieved up to the 17th harmonic order at 244.5MHz frequency. At the 17th harmonic mode-locking regime, bright and dark solitons coexist, exhibiting a uniform pulse spacing of 4.09ns. Spectral analysis reveals distinct peaks at 1909.4nm and 1902nm for the bright and dark solitons, respectively. The bright soliton shows a 1.62ps pulse width with a TBP of 0.317, indicating slight chirping. The bright and dark solitons exhibited a signal-to-noise ratio (SNR) of 81.5dB, demonstrating high stability attributed to the energy exchange and phase interactions between the solitons. © 2025 World Scientific Publishing Company.
Photonics Research Centre, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jalan Semarang 5, Malang, 65145, Indonesia; Nanotechnology and Catalysis Research Center, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
