Chirp laser stabilization system
US4660206A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1984 |
| Grant date | Apr 21, 1987 |
| Priority date | — |
| Expiry date | Jul 2, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/107
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A chirp laser system includes an intracavity electro-optical crystal modulated at a relatively high frequency, for example 250 kilohertz, to sweep the frequency of the transmitter laser above and below its nominal center frequency. One of the mirrors of the laser transmitter is adjustable to vary the length of the cavity and to shift the frequency of the transmitter laser. When the frequency of the transmitter laser is shifted, the output amplitude of the laser changes. With the center frequency of the laser at a maximum gain point, the amplitude of the output signals during positive and negative frequency excursions of the transmitter laser will be substantially symmetrical. However, if thermal or other effects cause the frequency of the laser to shift away from the maximum gain point, the output during positive and negative excursions will be asymmetrical. A small part of the output from the transmitter laser is sampled, and the amplitude during positive and negative frequency shift excursions is compared, using a square wave derived from the chirp modulating driver. Where the detected signals for the positive and negative frequency excursions are substantially equal, no change i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.