High-fidelity and adaptive forward-phase-based vibration sensing using a Wiener filter in DSCM systems under...

Area of Science:

• Optical Communications
• Signal Processing
• Sensor Technology

Background:

• Commercial coherent digital subcarrier multiplexing (DSCM) systems utilize frequency-domain pilot tones (FPTs) for critical functions like frequency offset estimation (FOE) and carrier phase estimation (CPE).
• Extracting vibration-induced phase information from these systems is crucial for sensing applications but is often limited by background noise, particularly laser phase noise.

Purpose of the Study:

• To propose and validate a high-fidelity and adaptive forward-phase-based vibration sensing technique.
• To improve the sensing signal-to-noise ratio (SSNR) by effectively suppressing background noise.
• To demonstrate the adaptive detection capabilities of the proposed method for various vibration waveforms.

Main Methods:

• A Wiener filter (WF) is applied to the phase information obtained from the carrier phase estimation (CPE) module in DSCM systems.
• The WF-based phase extraction is compared against traditional bandpass filter (BPF) methods.
• Experimental validation is performed using sinusoidal, amplitude-modulated continuous wave (AMCW), and frequency-modulated continuous wave (FMCW) vibrations.

Main Results:

• The WF method significantly suppresses sensing background noise originating from laser phase noise, outperforming traditional BPF methods.
• An 8 dB improvement in SSNR was achieved for 10 kHz sinusoidal vibration detection using the WF method compared to the BPF method.
• The WF method demonstrated adaptive detection of both AMCW and FMCW vibrations without requiring prior knowledge of their frequency or waveform.

Conclusions:

• The proposed WF-based vibration sensing offers high fidelity and adaptability in DSCM systems.
• This method provides a superior approach to phase extraction, enhancing SSNR and enabling versatile vibration detection.
• The WF technique presents a robust solution for advanced optical sensing applications.