Kerr-lens mode-locked lasers as ultra-low noise microwave sources

Summary form only given. Kerr-lens mode-locked (KLM) femtosecond lasers provide a dense comb of phase coherent reference frequencies and thus are versatile tools for optical frequency measurements. We demonstrate that the quantum-limited pulse timing noise level of such a laser is substantially smaller than the noise generated by state-of-the-art microwave oscillators.