Microfiber coupler with a Sagnac loop for water pollution detection.

Area of Science:

• Optoelectronics
• Chemical Sensing
• Environmental Monitoring

Background:

• Accurate measurement of chloride ion concentration is crucial for water resource quality assessment.
• Existing methods may lack sensitivity, cost-effectiveness, or simplicity for widespread monitoring.

Purpose of the Study:

• To propose and demonstrate a new chloride ion sensor.
• To achieve high sensitivity and a low detection limit for chloride ions.
• To explore applications in environmental and marine monitoring.

Main Methods:

• Fabrication of a microfiber coupler (10 μm diameter, 1 mm length) using the flame-brushing technique.
• Integration of the microfiber coupler into a Sagnac loop to enhance reflective properties.
• Experimental characterization of the sensor's performance in detecting chloride ion concentrations.

Main Results:

• The sensor achieved a maximum sensitivity of 423 pm/‰.
• The detection limit for chloride ion concentration was determined to be 0.447‰ at 1595 nm.
• The sensor exhibits a simple fabrication process, compact size, and low cost.

Conclusions:

• The proposed microfiber coupler Sagnac loop sensor is a promising tool for chloride ion detection.
• Its characteristics make it suitable for applications such as marine chloride detection and environmental safety monitoring.
• Potential applications include monitoring building corrosion and water pollution.