N.A.M. Rusni, H. Ahmad, M.Z. Samion, M.F. Ismail, K. Thambiratnam, Z. Mahmoodin
This work presents a passively Q-switched erbium-ytterbium codoped fiber laser (EYDFL) using a linear cavity design and SiO2 fabricated from rice husk ash (RHA) saturable absorber (SA). The SA exhibited a high modulation depth of 20.7% and a saturation intensity of 1.07 MW cm−2. At lower pump powers, the laser emitted continuous-wave at 1557 nm and 1567 nm. This phenomenon arises because the reflection spectrum of the fiber Bragg grating (FBG) and the Faraday mirror supports lasing at two distinct wavelengths. The dual-wavelength feature arises from the interplay between wavelength-selective FBG reflection and cavity-induced interference within the linear cavity. Although dual-wavelength operation can be mitigated by incorporating a subring cavity to enhance mode selectivity, the primary objective of this study is to investigate and demonstrate laser performance in a simple linear-cavity configuration without additional cavity modifications. Upon increasing the pump power beyond 1.08 W, stable Q-switched pulses at 1567 nm emerged. The system achieved a pulse duration of 4.81 µs, a repetition rate of 12.3 kHz, and a signal-to-noise ratio of 33 dB. As the pump power increases from 1.08 W to 1.6 W, the pulse duration decreases from 6.51 µs to 4.81 µs, indicating that Q-switched pulses become narrower at higher pump powers. In contrast, the repetition rate rises from 6.7 kHz to 12.3 kHz with increasing pump power. Hence, increasing the pump power leads to shorter pulse durations and higher repetition rates, demonstrating more efficient Q-switched pulse generation. This compact single linear-cavity EYDFL highlights the potential of RHA-derived SiO2 as a sustainable SA. © 2026 Astro Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Photonics Research Centre, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Institute for Advanced Studies, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Physics Department, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jalan Semarang 5, Malang, 65145, Indonesia; Universiti Kuala Lumpur British Malaysian Institute(UniKL BMI), Batu 8, Jalan Sungai Pusu, Selangor, 53100, Malaysia; Physics Department, Kulliyyah of Science, International Islamic University Malaysia, Bandar Indera Makhota, Kuantan, 25200, Malaysia; Medical Engineering Technology Section, Universiti Kuala Lumpur British Malaysian Institute (UniKL BMI), Batu 8, Jalan Sungai Pusu, Selangor, 53100, Malaysia
