Method of fiber transfer delay measurement based on phase quantization and delay synthesis

Area of Science:

• Optical Engineering
• Metrology
• Signal Processing

Background:

• Accurate measurement of fiber transfer delay (FTD) is crucial for high-speed optical communication systems.
• Existing methods face challenges with phase ambiguity and quantization errors, limiting measurement precision and range.

Purpose of the Study:

• To propose and demonstrate a novel method for fiber transfer delay (FTD) measurement.
• To overcome the phase ambiguity and quantization error issues inherent in current FTD measurement techniques.
• To achieve high-accuracy, high-resolution, and wide-range FTD measurements.

Main Methods:

• Utilizes phase quantization and delay synthesis for FTD measurement.
• Employs differential phase shift detection of frequency-multiplied RF signals.
• Incorporates a self-check and error-correction mechanism to mitigate quantization errors.

Main Results:

• Demonstrated a novel FTD measurement method with high reliability.
• Achieved measurement repeatability of approximately 0.018 ps over 80 seconds for a back-to-back fiber link.
• Proved a test resolution of 0.03 ps using a motorized tunable delay line.
• The system supports a large FTD measurement range up to 100 µs without dead zones.

Conclusions:

• The proposed phase quantization and delay synthesis method effectively solves the FTD phase ambiguity problem.
• The self-check and error-correction approach significantly enhances measurement reliability.
• The demonstrated system offers a precise, reliable, and wide-range solution for FTD measurement in optical systems.