High precision measurement of the free spectral range of an etalon
US7800763B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2007 |
| Grant date | Sep 21, 2010 |
| Priority date | — |
| Expiry date | Apr 17, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods, systems, apparatus and devices for using a modified PDH technique to measure the FSR of an etalon with one part per 104 precision. An embodiment of the method for measuring the free spectral range of an etalon can include generating a laser light from a laser source, generating a RF source signal, RF modulating the laser light with the RF source signal to produce an RF modulated laser signal, coupling the RF modulated laser signal through a circulator to the etalon, coupling a reflected RF signal from the etalon through the circulator to photo detector, converting the reflected RF signal to an electrical signal at the photo detector, amplifying the electrical signal, mixing the amplified electrical signal with a RF delayed source signal, linearly scanning a frequency of the RF source signal, and monitoring a peak-to-peak mixer voltage Vmixer during the linear scanning of the RF source signal frequency to detect a peak-to-peak minimum voltage when the RF modulation frequency is tuned approximately to a free spectral range of the etalon, the result having a precision greater than one part per 104 without the use of a high resolution optical spectrum analyzer or a tunable las…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.