Sensitivity-enhanced microwave-photonic optical fiber interferometry based on the Vernier effect

Area of Science:

• Photonics and Optical Sensing
• Interferometry
• Microwave Photonics

Background:

• Optical fiber interferometers are crucial for sensing applications.
• Enhancing measurement sensitivity in optical sensing remains a key challenge.
• The Vernier effect offers a potential mechanism for signal amplification.

Purpose of the Study:

• To propose and demonstrate an optical carrier microwave interferometry (OCMI)-based optical fiber interferometer system.
• To enhance measurement sensitivity for sensing applications using the Vernier effect.
• To investigate the performance of cascaded Fabry-Perot interferometers (FPIs) in an OCMI system.

Main Methods:

• Implementation of a single-FPI-OCMI system for temperature variation measurements.
• Cascading two FPIs with slightly different optical lengths to induce the Vernier effect.
• Tracking spectral shifts and envelope signal variations in the microwave domain for data analysis.

Main Results:

• Demonstration of temperature measurements using a single-FPI-OCMI system.
• Experimental validation of the Vernier effect in a cascaded FPI-OCMI system, leading to significantly enhanced sensitivity.
• Adjustable amplification factor for measurement sensitivity by tuning the FPI length ratio.

Conclusions:

• The proposed OCMI-based optical fiber interferometer system effectively enhances measurement sensitivity.
• The Vernier effect, implemented via cascaded FPIs, provides a tunable mechanism for sensitivity amplification.
• The system shows promise for advanced sensing applications requiring high precision.