Optical wavelength meter
US4172663A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 1977 |
| Grant date | Oct 30, 1979 |
| Priority date | — |
| Expiry date | Apr 27, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an optical wavelength meter, the wavelength of light to be measured, such as that obtained from a CW or pulsed laser, is directed through a tunable grating monochromator, serving as a bandpass filter, for passing light within the selected bandpass and determining, to the lowest degree of resolution, the wavelength of the light to be measured. Thence, the light is directed sequentially through a plurality of Fabry-Perot etalon interferometers of increasing degree of resolution. The interference patterns are sequentially directed onto a spatial detector. The radii of the first and second rings of the respective interference patterns are measured to derive fractional fringe order measurements of successively higher resolution, such that the wavelength of the light to be measured is determined in successively increasing steps of higher resolution. In a typical example, utilizing three Fabry-Perot etalons the wavelength of the light to be measured at, for example, 6328 angstroms is determined to be an absolute accuracy of .+-.200 megahertz.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.