Automatic feedback gain control for multiple channels in a doped optical fiber amplifier
US6175436A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 30, 1996 |
| Grant date | Jan 16, 2001 |
| Priority date | — |
| Expiry date | Jul 30, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/2912
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for controlling the gain in an erbium-doped fiber amplifier (EDFA) incorporated into a multi-wavelength communication system so as to amplify each of the wavelength signals. The amplifier operates near to saturation so that, if one or more of the multi-wavelength signals is removed from the transmission, the remaining channels are increasingly amplified, leading to problems with other components in the system which depend upon intensity. According to the invention, an optical signal at a wavelength that is not within any of the transmission channels is selectively fed back around the amplifier and caused to lase in a wavelength-filtered ring-laser configuration. The lasing signal governs the saturation of the amplifier such that any gain shed by a disappearing data signal is predominately used by the lasing signal, not by the remaining data signals. Thereby, the data signals do not experience gain variations dependent upon the number of data signals being amplified. In a chain of amplifiers on a long link, the wavelength of the lasing signal is chosen to lie within the gain flat band of the amplifier and is output from the equalized amplifier with the same e…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.