Automatic bias control for electro-optic modulators
US6046838A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1998 |
| Grant date | Apr 4, 2000 |
| Priority date | — |
| Expiry date | Dec 22, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/21
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The bias point of an electro-optic modulator, such as an Mach-Zender modulator, is automatically controlled. A pilot signal, preferably two pilot tones at different frequencies, is applied to the modulator. The output of the modulator then contains various components resulting from the pilot signal. An error signal is generated, preferably coherently, based on one of these components, termed the pilot component, which preferably is located at the difference frequency of the two pilot tones. A bias signal which controls the bias point of the modulator is adjusted based on the error signal. The coherent generation of the error signal facilitates feedback loops based on phase and/or amplitude control and also supports locking the electro-optic modulator to a bias point with a preselected slope (either negatively or positively sloping).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.