Investigation on single taper-based all-solid photonic bandgap fiber modal interferometers

Area of Science:

• Photonics
• Fiber optics
• Interferometry

Background:

• All-solid photonic bandgap (AS-PBG) fibers offer unique light guiding properties.
• Modal interferometry in optical fibers is a key technique for sensing applications.

Purpose of the Study:

• To demonstrate a single taper-based AS-PBG fiber modal interferometer.
• To investigate its performance for refractive index (RI) sensing.

Main Methods:

• Fabrication of AS-PBG fiber interferometers with specific taper dimensions (50-60μm diameter, ~3mm length).
• Superposition of the bandgap-guided fundamental core mode and an index-guided cladding supermode.
• Analysis of temperature coefficients and RI responsivities.

Main Results:

• Maximal RI sensitivity of ~3512.36 nm/RIU achieved at a 50μm taper diameter and RI of 1.423.
• Temperature coefficient is influenced by cladding supermode energy localization.
• Demonstrated a deep understanding of the modal-interferometric AS-PBG structure.

Conclusions:

• The developed AS-PBG fiber modal interferometer is a promising platform for high-sensitivity RI sensing.
• The study provides valuable insights into the structure-performance relationship for AS-PBG devices.
• Potential for future applications in various sensing fields.