High sensitivity Sagnac interferometric temperature sensor using stress region refractive index modulation

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Sensors
• Material Science

Background:

• Accurate temperature monitoring is crucial for environmental and industrial processes.
• Existing fiber optic sensors face challenges in sensitivity, linearity, or fabrication complexity.
• Refractive index modulation offers a potential avenue for enhanced sensor performance.

Purpose of the Study:

• To experimentally demonstrate a novel all-fiber temperature sensor.
• To investigate the temperature sensing characteristics of the proposed device.
• To assess the sensor's suitability for practical applications.

Main Methods:

• Fabrication of a sensor head comprising sections of polarization-maintaining fiber (PMF) and multi-mode fiber (MMF).
• Utilizing controlled fusion splicing and angular rotation of PMF sections to induce intentional refractive index modulation.
• Integration of the sensor head into a Sagnac loop configuration with a 3 dB coupler.
• Experimental characterization of temperature sensitivity and linearity over a specific temperature range.

Main Results:

• Successful demonstration of an all-fiber temperature sensor.
• Achieved a high temperature sensitivity of 1.49 nm/°C.
• Observed good linearity in temperature measurements within the range of 16°C to 55°C.
• The sensor fabrication process is straightforward.

Conclusions:

• The proposed all-fiber temperature sensor based on refractive index modulation is effective.
• The sensor offers high sensitivity and good linearity, suitable for practical temperature monitoring.
• Its easy fabrication and performance make it a promising candidate for environmental monitoring and industrial production.