Cascaded Fabry-Perot interferometer with thin film based on Vernier effect

Area of Science:

• Optical Fiber Sensing
• Interferometry
• Thin Film Optics

Background:

• The Vernier effect enhances optical fiber sensor sensitivity.
• Cascaded Fabry-Perot interferometers (FPIs) are key components in optical sensing.
• Thin films play a crucial role in modulating sensor performance.

Purpose of the Study:

• To establish a theoretical model for cascaded FPIs utilizing the Vernier effect.
• To analyze the sensitivity of envelope spectra, thin film, and mixed cavities.
• To experimentally demonstrate a novel FPI for temperature and gas pressure sensing.

Main Methods:

• Theoretical modeling of cascaded FPIs with thin films based on the Vernier effect.
• Qualitative analysis of envelope spectra, thin film, and air-thin film mixed cavity sensitivities.
• Experimental fabrication and testing of a novel FPI using hollow-core fiber and polydimethylsiloxane (PDMS) thin film.

Main Results:

• A theoretical model for cascaded FPIs with Vernier effect was established.
• The proposed FPI demonstrated high temperature sensitivity (3.07 nm/°C) and gas pressure sensitivity (23.07 nm/MPa).
• A high magnification factor of 17 was achieved, with experimental results aligning with theoretical predictions.

Conclusions:

• The developed theoretical model accurately predicts the performance of cascaded FPIs for sensing applications.
• The novel FPI design exhibits excellent stability, reversibility, and repeatability.
• This technology offers a promising solution for advanced optical fiber sensing applications.