ABSOLUTE DISTANCE METROLOGY FOR LONG DISTANCES WITH DUAL FREQUENCY SWEEPING INTERFEROMETRY |
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| Alexandre Cabral, Manuel Abreu, José M. Rebordão |
- Abstract:
- Coherent absolute distance interferometry is one of the most interesting techniques for length metrology. In frequency sweeping interferometry (FSI), measurements are made without ambiguity, by using a synthetic wavelengths resulting from a frequency sweep. Accuracy is mainly dependent on the capability to measure the synthetic wavelength, using a Fabry-Perot interferometer (FP) to count resonances as frequency sweeps, and therefore the number of detected synthetic fringes. For large ranges, the number of fringes dominates performance, leading to a linear decrease of the accuracy with range. By increasing the size of the interferometer reference arm, and measuring both the distance and the reference arm independently, it is possible to maintain small distance high accuracy measurements, even for much larger range.
In the context of the ESA-PROBA3 mission (coronagraph and demonstration of metrology for free-flying formation), we implemented a FSI sensor composed of a mode-hop free frequency sweep external cavity diode laser, a high finesse FP (to measure accurately the frequency sweep range) and a dual measurement system to enable the measurements at 150 m with an accuracy at the tens of micrometer level.
In this paper we describe the implementation of the prototype and present the first results obtained for a long range measurement. - Keywords:
- absolute distance measurement, interferometry, tunable lasers
- Download:
- IMEKO-WC-2009-TC14-647.pdf
- DOI:
- -
- Event details
- Event name:
- XIX IMEKO World Congress
- Title:
Fundamental and Applied Metrology
- Place:
- Lisbon, PORTUGAL
- Time:
- 06 September 2009 - 11 September 2009