Generation of watt-level Kerr-lens mode-locked Yb:CYA laser at 1-GHz repetition rate

We present a Kerr-lens mode-locked (KLM) femtosecond Yb:CYA laser at 1.04-GHz repetition rate, pumped by a single-mode fiber laser, which achieves an average output power of 1.37 W with a pulse duration of 109 fs. A comparative analysis of three pump sources is provided, along with a detailed description of the optical and thermal properties of Yb:CYA crystals. The design and optimization of the resonator’s lenses and dispersion are thoroughly addressed, and the mode-locking process via Kerr-lensing is discussed in detail. Additionally, we provide a perspective on potential improvements, including increasing the pump power, enhancing the repetition rate, and reducing the pulse duration. This study contributes to the advancement of watt-level GHz femtosecond laser generation and its applications.