Abstract

Frequency-stabilized mode-locked femtosecond lasers are a cornerstone of modern optical frequency metrology and have allowed the demonstration of many new technologies, including optical atomic clocks, novel broadband spectroscopy, and the synthesis of ultra-low phase noise optical and microwave signals. At present, optical frequency combs are predominantly based on two femtosecond laser technologies: titanium:sapphire lasers and Er and Yb:fibre lasers. Here, an alternative approach employing a 180-MHz repetition rate, diode-pumped Yb-doped tungstate (Yb:KYW) frequency comb is demonstrated. In addition to being a compact, low-cost, and efficient optical frequency comb, the Yb:KYW frequency comb has excellent noise properties. We show that when frequency-stabilized the Yb:KYW can be used to generate microwave signals having frequency stability significantly better (>30×) than is achievable with conventional quartz or dielectric-based oscillators.

© 2009 IEEE