Highly sensitive fiber optic current sensor using circular thin copper rod to directly fabricate Fabry-Perot cavity

Area of Science:

• Optoelectronics
• Sensor Technology
• Materials Science

Background:

• Accurate current measurement is crucial for industrial production.
• Existing sensors may lack the required sensitivity or robustness.
• Fiber-optic sensors offer potential advantages in harsh environments.

Purpose of the Study:

• To develop and experimentally verify a novel high-sensitivity fiber-optic current sensor.
• To enhance current measurement capabilities for industrial applications.
• To investigate the use of a Vernier effect with a Fabry-Perot interferometer for improved sensitivity.

Main Methods:

• A Fabry-Perot interferometer (FPI) was fabricated directly on a thin copper rod.
• Two single-mode fibers were aligned to form the FPI cavity on the copper rod.
• A Vernier effect sensor (S1) was constructed using the FPI as the sensing element.

Main Results:

• A single FPI demonstrated a current square sensitivity of 568 ± 10 pm/A².
• The Vernier effect sensor S1 achieved a current square sensitivity of 4.7 ± 0.1 nm/A².
• The enhanced sensor exhibited an 8.5-fold increase in sensitivity compared to the single FPI.

Conclusions:

• The developed fiber-optic current sensor is highly sensitive, robust, and easy to fabricate.
• The Vernier effect significantly enhances the sensitivity of FPI-based current sensors.
• This sensor provides a simple and effective solution for industrial current measurement.