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Injected current reshaping in distance measurement by laser self-mixing interferometry.
Applied Optics
|October 17, 2014
Summary
This study enhances laser range finding using self-mixing interferometry (SMI) by linearizing laser frequency. This method improves distance resolution for compact sensors, achieving better than 20 μm accuracy.
Area of Science:
- Optics and Photonics
- Laser Technology
- Metrology
Background:
- Self-mixing interferometry (SMI) offers compact laser range finding for precision measurements.
- Nonlinearity in laser frequency tuning limits the resolution of traditional SMI systems.
Purpose of the Study:
- To investigate the mechanism of laser frequency nonlinearity under injected current tuning.
- To propose and validate a current reshaping method for linearizing laser frequency in SMI.
- To enhance the distance resolution of SMI sensors.
Main Methods:
- Numerical simulation incorporating temperature and carrier concentration changes to demonstrate nonlinearity.
- Complex wavelet analysis for experimental proof of nonlinearity.
- Development of a current reshaping algorithm based on experimental wavelength-current data.
Main Results:
- Nonlinearity in laser frequency tuning was confirmed through simulation and experiment.
- The proposed current reshaping method effectively suppresses nonlinearity.
- Improved distance resolution of better than 20 μm was achieved over a 2.4-20.4 cm range.
Conclusions:
- Laser frequency linearization via current reshaping significantly enhances SMI performance.
- The developed technique enables higher resolution in compact laser range finding sensors.
- Further analysis considered the impact of tuning parameters and error sources on performance.
