Generation of Q-switched fiber laser at 1.0-, 1.55-and 2.0-mu m employing a spent coffee ground based saturable absorber

• Main Authors: Rusdi, Muhammad Farid Mohd, Jafry, Afiq Arif Aminuddin, Latiff, Anas Abdul, Rosol, Ahmad Haziq Aiman, Ab Rahman, Mohd Fauzi, Kasim, Nabilah, Abdul Khudus, Muhammad Imran Mustafa Abdul, Ahmad, Harith, Harun, Sulaiman Wadi
• Format: Article
• Published: Elsevier 2021
• Subjects: QC Physics; TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/34260/

Spent coffee ground (SCG) was demonstrated as saturable absorber (SA) for Wideband Q-switched fiber lasers generation. The SCG SA has a broad linear absorption that covers from 1000 nm to 2000 nm wavelength and a modulation depth of 30% at 1.55-mu m region. Through purification process, the finer SCG powder is obtained, and be embedded with a polyvinyl alcohol for thin film formation. To realize Q-switching operation lasers, a fabricated SCG film was integrated into three different fiber laser cavities including ytterbium-doped fiber laser, erbium-doped fiber laser, and thulium-doped fiber laser. A peak wavelength has obtainable at 1031 nm, 1563 nm, and 1976 nm for 1-, 1.55-, and 2- mu m regions, respectively. The shortest pulse width of 4.80 mu s and maximum pulse energy of 0.152 mu J are observed from the YDFL cavity. RF spectrum shows the signal-to-noise ratio for all regions is above 35 dB, indicates a stable pulsing generation. Our technique opens the door for unlimited materials SA from environmentally friendly resources which contribute to sustainable effort.