A Wavelet Derivative Spectrum Length Method of TFBG Sensor Demodulation.

Area of Science:

• Optoelectronics
• Photonics
• Sensor Technology

Background:

• Tilted fibre Bragg gratings (TFBGs) offer high sensitivity for refractive index measurements.
• Accurate metrological parameters in TFBG sensing require effective spectrum demodulation methods.
• Existing spectral length algorithms can be limited by noise and resolution.

Purpose of the Study:

• To improve the spectral length algorithm for enhanced spectrum demodulation in TFBG sensors.
• To introduce a novel method utilizing wavelet transform for numerical derivative approximation.
• To enhance the resolution and noise immunity of refractive index measurements.

Main Methods:

• Implementation of a wavelet transform for approximating the numerical derivative of spectral data.
• Treating the spectral length parameter as the sum of derivative filter responses.
• Utilizing the scale parameter of the wavelet transform for adjustable smoothing and noise filtering.

Main Results:

• The proposed wavelet transform method effectively approximates the spectral length, reducing high-frequency noise.
• This approach provides a simple way to control smoothing by adjusting the wavelet scale parameter.
• Experimental analysis demonstrates a linear method with superior resolution compared to the contour length algorithm, even at low signal-to-noise ratios.

Conclusions:

• Wavelet transform-based spectral length approximation offers a robust and high-resolution demodulation technique for TFBG sensors.
• The method enhances measurement accuracy and reliability, particularly in noisy optical signal environments.
• This advancement contributes to the development of more precise refractive index sensing technologies.