Photonic crystal fiber Mach-Zehnder interferometer for refractive index sensing

Area of Science:

• Optics and Photonics
• Sensing Technologies
• Materials Science

Background:

• Refractive index (RI) sensing is crucial for various applications.
• Photonic crystal fibers (PCFs) offer unique light manipulation properties.
• Developing robust and sensitive RI sensors remains an active research area.

Purpose of the Study:

• To demonstrate a refractive index sensor based on a photonic crystal fiber (PCF) interferometer.
• To investigate the performance of the PCF interferometer for sensing aqueous solutions.
• To evaluate the sensor's resolution and applicability in different fields.

Main Methods:

• Fabrication of a PCF interferometer by fusion splicing PCF between single-mode fibers.
• Utilizing the collapsed air holes in PCF for core-cladding mode coupling, forming a Mach-Zehnder interferometer.
• Employing wavelength-shift interrogation to analyze transmission spectrum shifts in response to varying RI.

Main Results:

• The PCF interferometer exhibited a sinusoidal interference pattern.
• The transmission spectrum showed distinct shifts when exposed to different refractive indices.
• Achieved high resolution (1.02 × 10⁻⁴ - 9.04 × 10⁻⁴ RIU) for RI sensing in the range of 1.333 to 1.422.

Conclusions:

• The developed PCF interferometer is a promising platform for sensitive refractive index measurements.
• The sensor shows potential for applications in chemical, biological, and environmental monitoring.
• This technology offers a valuable tool for civil engineering and other fields requiring RI detection.