Thulium-holmium doped fiber laser mode-locking with hafnium disulfide (HfS2) coated on D-shaped fiber

• Published in: Optik (Stuttgart) Vol. 246; p. 167785
• Main Authors: Ahmad, H., Kahar, N.H. Abdul, Yusoff, N., Reduan, S.A.
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 01.11.2021
• Subjects: D-shaped fiber; Hafnium disulfide; Mode-locking; Saturable absorber; Thulium-holmium doped fiber laser; Mode-locking; D-shaped fiber; Thulium-holmium doped fiber laser; Hafnium disulfide; Saturable absorber
• ISSN: 0030-4026; 1618-1336
• DOI: 10.1016/j.ijleo.2021.167785

The performance of hafnium disulfide (HfS2) was demonstrated in this study to generate a mode-locked pulse in a thulium-holmium doped fiber laser (THDFL). The drop-cast method was used to deposit HfS2 solution onto a D-shaped single-mode optical fiber. The fabricated D-shaped fiber had a modulation depth and saturation intensity of 12.3% and 7.53 MW/cm2, respectively, according to nonlinear optical absorption measurements. The evanescent wave interaction with the HfS2 based SA embedded on a D-shaped optical fiber resulted in a mode-locked pulse at a pump power of 208.6 mW with a central wavelength and pulse duration of 1916.29 nm and 1.509 ps, respectively. Meanwhile, raising the pump power to 208.6 mW results in a repetition rate of 11.10 MHz. The output shows a stable mode-locked THDFL pulse with a signal to noise ratio (SNR) of around 75.74 dB. Overall, this research focuses on the potential of HfS2 used as SA coated on a D-shaped optical fiber for the generation of short pulses in a 2 µm band region. •First demonstration of mode-locking using HfS2 in Tm/Ho-doped fiber laser cavity.•HfS2 drop-casted onto a D-shaped fiber for simple incorporation of an SA.•Mode-locking operation at 1916.29 nm with a peak power of 33.43 W.•Signal to noise ratio of a mode-locked pulse of 75.74 dB with 1.509 ps pulse width.