Absolute phase marking technology and fiber-optic remote coherent phase transmission

Area of Science:

• Optical Physics
• Metrology
• Telecommunications Engineering

Background:

• Fiber-optic time and frequency synchronization offers high performance but faces challenges with phase signal ambiguity and initial uncertainty.
• Existing methods struggle to achieve precise coherent phase transmission over long distances.

Purpose of the Study:

• To develop a novel technology for ultra-high precision remote coherent phase transmission over optical fibers.
• To address and resolve phase period ambiguity and initial phase uncertainty in fiber-optic synchronization.

Main Methods:

• Developed absolute phase marking technology using high-speed digital logic and zero-crossing detection.
• Implemented an optimized control strategy for picosecond-level phase marking and pulse generation.
• Combined synchronized frequency signals for phase measurement with pulse-per-second signals for ambiguity elimination.

Main Results:

• Achieved picosecond-level absolute phase marking and ultra-low jitter (3.3 ps peak-to-peak over 10,000 s) in remote coherent phase transmission.
• Demonstrated a coherent phase transmission uncertainty of 2.577 ps.
• Successfully eliminated phase period ambiguity and determined initial phase and transmission delay.

Conclusions:

• The developed technology significantly enhances phase coherence in fiber-optic time and frequency transmission.
• Provides a new method for picosecond-level reference phase marking and high-precision remote coherent phase transmission.
• Shows broad applicability in coherence-dependent fields, including radar networking.