Method and apparatus for reducing optical signal speckle
US8750341B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2008 |
| Grant date | Jun 10, 2014 |
| Priority date | — |
| Expiry date | Nov 12, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/0652
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical signal generator is configured with an associated control system and driver configured to reduce speckle. Speckle reduction occurs by pulsing the drive signal between a first current level and a second current level. These pulses force the optical signal generator to introduce oscillations into the optical signal. The coherence of the emitted light is reduced during the period of oscillations in the optical signal, which reduces speckle. In one embodiment, the pulsing of the drive signal brings the drive signal down to a level near or below threshold, which in turn intermittently turns off the optical signal output. Returning the optical signal to a desired optical output intensity introduces the speckle reducing oscillation. The pulse frequency, and duty cycle is controlled by a duty cycle control signal to modulate overall optical power and adjust amount of despeckle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.