Khalil Kamaruzzaman, Harith Ahmad, Mousa Hussein
A high-power femtosecond holmium-doped fiber laser (HDFL) employing a chirped-pulse amplification (CPA) scheme with two cascaded single-clad amplifier stages is demonstrated. The oscillator generated stable soliton pulses centered at 2071.9 nm with a 15.58 MHz repetition rate. The pulses were temporally stretched using a 20 m UHNA4 fiber and subsequently amplified in two stages of single-clad Ho-doped fiber amplifiers. This CPA configuration effectively suppressed nonlinear pulse distortion, enabling high-energy amplification while preserving pulse quality. The system achieved a maximum average output power of 1.05 W, which corresponds to a pulse energy of 67.5 nJ, a pulse duration of 329 fs, and a peak power of 205 kW. To the best of our knowledge, this work represents the first reported CPA-based HDFL employing two-stage single-clad amplification, achieving watt-level average power with femtosecond soliton characteristics in an entirely all-fiber configuration. The proposed design provides a compact, efficient approach to high-power femtosecond pulse generation near 2 µm, offering a promising platform for mid-infrared frequency conversion, nonlinear optics, and ultrafast spectroscopy. © 2026 Elsevier Inc.
Institute for Advanced Studies, Advanced Studies Complex, Kuala Lumpur, 50603, Malaysia; Photonics Research Centre, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Department of Physics, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Malang, 65145, Indonesia; Universiti Kuala Lumpur British Malaysian Institute (UniKL, BMI), Batu 8, Selangor, Jalan Sungai Pusu, 53100, Malaysia; Department of Electrical and Communication Engineering, United Arab Emirates University, Al Ain, United Arab Emirates
