Long-term frequency-stabilized optical frequency comb based on a turnkey Ti:sapphire mode-locked laser

We report a long-term frequency-stabilized optical frequency comb at 530-1100 nm based on a turnkey Ti:sapphire mode locked laser. With the help of a digital controller, turnkey operation is realized for the Ti:sapphire mode-locked laser. Under optimized design of the laser cavity, the laser can be mode-locked over a month, limited by the observation time. The combination of a fast piezo and a slow one inside the Ti:sapphire mode-locked laser allows us to adjust the cavity length with moderate bandwidth and tuning range, enabling robust locking of the repetition rate (f(r)) to a hydrogen maser. By combining a fast analog feedback to pump current and a slow digital feedback to an intracavity wedge and the pump power of the Ti:sapphire mode-locked laser, the carrier envelope offset frequency (f(ceo)) of the comb is stabilized. We extend the continuous frequency-stabilized time of the Ti:sapphire optical frequency comb to five days. The residual jitters of fr and fceo are 0.08 mHz and 2.5 mHz at 1 s averaging time, respectively, satisfying many applications demanding accuracy and short operation time for optical frequency combs.

Automated summary

This study presents a long-term frequency-stabilized optical frequency comb based on a Ti:sapphire laser, achieving automated operation and stable repetition rate through optimized laser cavity design. By combining fast and slow piezos, as well as analog and digital feedback, the carrier envelope offset frequency was successfully stabilized, extending the continuous stability time to five days. The residual jitters of the repetition rate and carrier envelope offset frequency both meet the requirements for various applications demanding precision and short operation time for optical frequency combs.