Temperature-insensitive fiber-optic tip sensors array based on OCMR for multipoint refractive index measurement

Area of Science:

• Photonics and Optical Sensing
• Biomedical Engineering
• Materials Science

Background:

• Accurate refractive index measurement is crucial for biochemical analysis.
• Existing sensors often face challenges with temperature sensitivity and multipoint capabilities.
• Fiber-optic sensors offer potential for miniaturization and remote sensing.

Purpose of the Study:

• To develop and demonstrate a temperature-insensitive fiber-optic tip sensor array for multipoint refractive index measurement.
• To evaluate the sensor array's resolution and temperature-refractive index cross-sensitivity.
• To explore the potential integration of the sensor array into chip-based biochemical sensing systems.

Main Methods:

• Fabrication of a fiber-optic tip sensor array using cleaved fiber end-faces.
• Spatial multiplexing of sensing tips via a fiber-optic splitter with varied delay fiber lengths.
• Utilizing optical carrier based on microwave reflection (OCMR) for refractive index detection.
• Experimental validation of the eight-tip sensor array's performance.

Main Results:

• Achieved a high refractive index resolution of 3.60 × 10^-6 RIU.
• Demonstrated low temperature-refractive index cross-sensitivity of 3.74 × 10^-7 RIU/°C.
• Successfully performed multipoint refractive index measurements using the developed array.

Conclusions:

• The proposed temperature-insensitive fiber-optic sensor array provides a robust platform for precise multipoint refractive index sensing.
• The sensor's performance metrics indicate suitability for demanding biochemical sensing applications.
• The array's design facilitates integration into compact, chip-based sensing devices.