Double etalon optical wavelength reference device
US6498800B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2000 |
| Grant date | Dec 24, 2002 |
| Priority date | — |
| Expiry date | Aug 10, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/18388
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A compact wavelength monitoring and control assembly for a narrow band (i.e., laser) source is provided, comprising two narrow bandpass, wavelength selective transmission filter elements of Fabry-Perot structure through which two separate collimated beams from a laser source are directed onto two photodetectors. The spacing of the multiple transmission maxima for one etalon is chosen to match that of the desired set of frequencies to be used for locking purposes. The spacing of the transmission maxima for the second etalon is used, in combination with a dielectric filter, to generate a wavelength fiducial to denote an absolute frequency. The spacing of the second etalon is chosen to be much wider than the frequency grid etalon. A control circuit processes the simultaneously acquired signals from the two detectors as the laser wavelength is varied. The device functions as an optical wavelength discriminator in which the detectors convert optical energy to current (or voltage) for a feedback loop for controlling the laser source. Any one of a large number of discrete, predetermined wavelengths may be chosen for locking using the same device. The system is compact and may be packaged …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.