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Fringe double for self-mixing interference based on the narrow transmission spectrum mapping
Junbao Chen1, Ming Wang2, Wei Xia2
1Department of Information Technology, Nanjing Forest Police College, Nanjing 210023, People's Republic of China.
The Review of Scientific Instruments
|October 2, 2020
Summary
A new fringe doubling technique using a Fabry-Pérot cavity enhances self-mixing interferometry (SMI). This method simplifies signal processing and improves displacement and velocity measurement resolution.
Area of Science:
- Optics and Photonics
- Interferometry
- Laser Physics
Background:
- Self-mixing interferometry (SMI) is a widely used technique for displacement and velocity sensing.
- Traditional SMI systems can face challenges with signal processing complexity and measurement resolution.
Purpose of the Study:
- To propose a novel fringe doubling scheme for self-mixing interferometry.
- To leverage a Fabry-Pérot cavity to enhance SMI signal characteristics.
Main Methods:
- A novel fringe doubling scheme utilizing a Fabry-Pérot (F-P) cavity is introduced.
- The scheme maps the narrow transmission spectrum of the F-P cavity to the self-mixing interference (SMI) signal.
- Optical frequency modulation from SMI sweeps the F-P cavity's transmission spectrum, causing fringe doubling.
Main Results:
- The proposed method generates a doubled SMI signal with enhanced fringe characteristics (sharp, neat, stable).
- The doubled SMI signal is suitable for displacement reconstruction using fringe counting.
- The technique facilitates velocity monitoring via joint time-frequency analysis.
Conclusions:
- The novel fringe doubling scheme simplifies signal processing in SMI systems.
- This method has the potential to significantly improve the resolution of SMI measurement systems.
- The use of an F-P cavity offers a stable and precise platform for enhanced interferometric measurements.
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