Low-cost refractive index sensor based on a fiber Mach-Zehnder interferometer fabricated by chemical etching method

Area of Science:

• Optics and Photonics
• Fiber Optic Sensors
• Interferometry

Background:

• Refractive index sensing is crucial for biochemical analysis.
• Traditional refractometers can be complex and expensive.
• Fiber optic interferometers offer potential for miniaturized and sensitive measurements.

Purpose of the Study:

• To propose and demonstrate a new refractometer based on a fiber Mach-Zehnder interferometer.
• To investigate the fabrication and performance of an H-shaped optical fiber interferometer.
• To evaluate its sensitivity and applicability for refractive index sensing.

Main Methods:

• Fabrication of an H-shaped fiber interferometer by splicing polarization-maintaining fiber between single-mode fibers.
• Utilizing chemical corrosion for device manufacturing with real-time monitoring.
• Experimental investigation of spectral characteristics and refractive index sensing performance.

Main Results:

• Successful demonstration of a fiber Mach-Zehnder interferometer with an H-shaped structure.
• Achieved ultra-high sensitivity of 105502.51 nm/RIU for refractive index sensing.
• Demonstrated usability even when analyte refractive index is close to fiber material.

Conclusions:

• The proposed H-shaped fiber interferometer is a cost-effective and simple device for refractometry.
• It offers excellent sensitivity for high-accuracy biochemical detection.
• The fabrication process is favorable, allowing for parallel processing and avoiding expensive equipment.