Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120...

Area of Science:

• Physics
• Metrology
• Optical Engineering

Background:

• Precision time synchronization is crucial for applications like GPS, interferometry, and fundamental physics research.
• Optical fiber links enable high-stability frequency dissemination, but require initial alignment and periodic timing corrections.
• Existing methods face challenges in maintaining precise temporal alignment over long distances.

Purpose of the Study:

• To demonstrate a novel time synchronization technique using an ultra-stable frequency transfer system via commercial optical fiber.
• To achieve high-precision time synchronization with minimal timing deviation over a 120-km link.
• To validate the effectiveness of feed-forward digital compensation (FFDC) for phase noise and temporal alignment.

Main Methods:

• Utilized an optical frequency comb for ultra-stable frequency transfer over a 120-km commercial fiber link.
• Implemented a feed-forward digital compensation (FFDC) technique for phase noise compensation and temporal basis alignment.
• Measured fractional frequency instability and timing deviation to evaluate synchronization performance.

Main Results:

• Achieved a fractional frequency instability of 6.18 × 10(-20) at 2000 s.
• Demonstrated a timing deviation of 0.6 ps over a 1500 s interval.
• The FFDC technique effectively compensated for phase noise and aligned temporal bases.

Conclusions:

• The demonstrated optical frequency comb-based time synchronization system provides unprecedented precision over long-haul fiber links.
• The FFDC technique is a robust solution for phase noise compensation and temporal alignment in fiber-based time transfer.
• This technology has potential applications in multi-node fiber networks requiring precise time synchronization.