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Passive Homodyne Phase Demodulation Technique Based on LF-TIT-DCM Algorithm for Interferometric Sensors.
Wanjin Zhang1,2, Ping Lu1,2, Zhiyuan Qu1
1Wuhan National Laboratory for Optoelectronics (WNLO) and National Engineering Laboratory for Next Generation Internet Access System, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
A new passive homodyne phase demodulation technique using the linear-fitting trigonometric-identity-transformation differential cross-multiplication (LF-TIT-DCM) algorithm offers a large dynamic range and wide frequency band for phase signal demodulation.
Area of Science:
- Optics and Photonics
- Signal Processing
- Interferometry
Background:
- Passive homodyne phase demodulation is crucial for various optical sensing applications.
- Traditional quadrature demodulation methods can struggle with small signals and are sensitive to optical power fluctuations.
- Existing ellipse fitting algorithms may fail when the interferometric signals degenerate.
Purpose of the Study:
- To introduce a novel passive homodyne phase demodulation technique.
- To demonstrate the effectiveness of the linear-fitting trigonometric-identity-transformation differential cross-multiplication (LF-TIT-DCM) algorithm.
- To overcome limitations of traditional methods, particularly in demodulating small signals and reducing sensitivity to optical power.
Main Methods:
- Development of a passive homodyne phase demodulation technique utilizing the LF-TIT-DCM algorithm.
- Implementation of an anti-phase dual wavelength demodulation system with an interferometric phase difference of π.
- Comparison with traditional quadrature dual wavelength demodulation systems employing ellipse fitting algorithms.
Main Results:
- The proposed LF-TIT-DCM algorithm enables phase demodulation with a large dynamic range and wide frequency band.
- The anti-phase dual wavelength system effectively overcomes the limitations of ellipse fitting algorithms for small signals.
- Experimental results show a significantly larger dynamic range compared to traditional quadrature systems.
- The anti-phase system exhibits minimal influence from optical power variations.
Conclusions:
- The LF-TIT-DCM algorithm provides a robust and versatile solution for passive homodyne phase demodulation.
- The anti-phase dual wavelength demodulation system offers superior performance in terms of dynamic range and stability.
- This technique presents a significant advancement for applications requiring precise phase measurement under varying conditions.
