Phase-sensitive correlation optical time-domain reflectometer using quantum phase noise of laser light.

Area of Science:

• Photonics
• Optical sensing
• Fiber optics

Background:

• Dynamic perturbations in optical fibers pose challenges for monitoring and localization.
• Existing methods may lack the sensitivity or precision required for detecting subtle changes.

Purpose of the Study:

• To propose and demonstrate a novel phase-sensitive correlation optical time-domain reflectometer (OTDR).
• To enable detection and precise localization of dynamic perturbations along a single-mode optical fiber.

Main Methods:

• Utilizing quantum phase fluctuations from a coherent DFB diode laser.
• Generating random probe signals via an interferometer with an optical path difference exceeding coherence length.
• Calculating cross-correlation functions between probe and return signals to obtain OTDR traces.
• Monitoring temporal variations in correlation amplitude for perturbation detection and localization.

Main Results:

• Successfully generated speckle-like OTDR traces.
• Demonstrated detection and localization of perturbations using weak reflectors (fiber Bragg gratings).
• Proof-of-concept experiments validated the proposed method's effectiveness.

Conclusions:

• The proposed phase-sensitive correlation OTDR is a simple yet effective approach for dynamic perturbation monitoring.
• This technique offers a promising solution for real-time detection and localization in fiber optic sensing applications.