Compact and Ultra-Stable Fiber-Photonic Stabilization Methods of Optical Frequency Combs

We show that timing and comb-line of optical frequency combs can be directly stabilized to the delay time of a compact 1-km-long optical fiber link spool (with several cm diameter) with (sub-)femtosecond-level integrated jitter and down to 10
⁻¹
s-level frequency instability.