Polarization-independent tilted fiber Bragg grating surface plasmon resonance sensor based on spectrum optimization

Area of Science:

• Photonics
• Optical Sensing
• Nanotechnology

Background:

• Surface Plasmon Resonance (SPR) sensors offer high sensitivity but are often affected by polarization changes.
• Tilted Fiber Gratings (TFBG) are versatile photonic devices for various optical applications.
• Polarization-dependent performance limits the practical use of fiber-optic sensors.

Purpose of the Study:

• To demonstrate polarization-independent fiber-optic SPR sensors.
• To achieve stable and reliable SPR sensing by mitigating polarization sensitivity.
• To enhance the performance of TFBG-based SPR sensors.

Main Methods:

• Experimental demonstration of polarization multiplexing schemes in a TFBG.
• Utilizing a polarization beam splitter (PBS) with orthogonal polarized lights.
• Employing a Faraday Rotator Mirror (FRM) for polarization multiplexing.
• Exciting SPR by aligning p-polarized light with the TFBG plane.

Main Results:

• Achieved polarization-independent SPR reflection spectra.
• Demonstrated that spectra are independent of light source and fiber perturbations.
• Obtained a polarization-independent TFBG-based SPR refractive index (RI) sensor.
• Reported high wavelength sensitivity (555.14 nm/RIU) and amplitude sensitivity (1724.92 dB/RIU).

Conclusions:

• Polarization multiplexing in TFBGs effectively eliminates polarization dependency in SPR sensors.
• The developed sensor exhibits robustness against mechanical perturbations.
• This approach offers significant advantages for practical, high-performance fiber-optic sensing applications.