Composite second-order bias control schemes
US6392779B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 2000 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Sep 5, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2210/075
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A bias control system is adapted to reduce composite second order distortions in an electro-optic modulator. The bias control system includes a pilot tone generator that generates a first pilot tone at a first frequency and a second pilot tone at a second frequency. The first and second tones are swept in frequency over a predetermined frequency range with a predetermined sweep rate, to spectrally spread third order distortion products over a larger frequency band, allowing the amplitude of the pilot tones to be increased, thereby increasing the gain of the bias control circuit. The bias control system further includes an optical detector for sampling the output of the electro-optic modulator, wherein the sampled optical output includes a distortion product resulting from the first and second pilot tones, and a feedback control circuit coupled to the optical detector and to the pilot tone generator for generating an error signal based on the distortion product in the sampled optical output for controlling the bias point of the electro-optic modulator. The bias control system preferably holds the difference between the frequency of the first pilot tone and the frequency of the secon…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.