Ultra-sensitive current sensor based upon a thermal-sensitive FPI and conductive material combination.

Area of Science:

• Optoelectronics
• Sensor Technology
• Materials Science

Background:

• Accurate current sensing is crucial in various industrial applications.
• Traditional current sensors face limitations in sensitivity and cost.
• Fabry-Perot interferometers (FPIs) offer potential for high-sensitivity measurements.

Purpose of the Study:

• To develop an ultra-high sensitivity current sensor.
• To investigate the use of thermal-sensitive FPIs for current measurement.
• To enhance sensor sensitivity using a vernier effect.

Main Methods:

• Fabrication of thermal-sensitive FPIs (FPI1 and FPI2) using polydimethylsiloxane (PDMS).
• Integration of FPIs with conductive copper rods to convert current-induced heat into measurable temperature changes.
• Construction of a sensor (S1) by combining FPI2 with a current-insensitive reference interferometer (FPI3) to induce a vernier effect.

Main Results:

• Individual FPIs demonstrated high temperature sensitivity (2.30 nm/°C and 1.75 nm/°C).
• The sensor S1 achieved a significantly enhanced current square sensitivity of 28.97 nm/A², a nearly 12-fold improvement over FPI2.
• The developed sensor exhibited good measurement repeatability and static stability.

Conclusions:

• The proposed FPI-based sensor with a vernier effect provides ultra-high sensitivity for current measurement.
• The sensor offers a cost-effective, easily manufactured, and repeatable solution.
• This work presents an innovative design for high-performance current sensing.