Ghost-peak-based estimation of modulation amplitude in optical correlation-domain reflectometry.

Area of Science:

• Optoelectronics
• Metrology
• Optical Engineering

Background:

• Accurate modulation amplitude evaluation is crucial for spatial resolution in optical correlation-domain reflectometry (OCDR).
• Conventional methods require complex, costly auxiliary equipment like spectrum analyzers.
• Existing techniques increase system complexity and expense.

Purpose of the Study:

• To propose a simple, accurate method for direct modulation amplitude estimation within OCDR.
• To enable quantitative estimation without external instruments.
• To enhance OCDR system stability and calibration.

Main Methods:

• Exploiting ghost peaks generated by a small frequency shift in the optical path.
• Analytically relating ghost-peak positions to modulation amplitude via a derived expression.
• Validating the method through experimental comparison with heterodyne detection.

Main Results:

• The proposed method accurately estimates modulation amplitude directly within the OCDR setup.
• Experimental results show agreement with heterodyne detection, with errors below 1.4%.
• The derived analytical formula demonstrates high precision with deviations under 0.015%.

Conclusions:

• The developed technique offers a compact, self-contained solution for OCDR modulation amplitude evaluation.
• This method simplifies OCDR systems by removing the need for auxiliary equipment.
• It provides a foundation for more stable and easily calibrated future correlation-domain reflectometry implementations.