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 modelocked 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 (fr) 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 (fceo) 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.