Optical transmission system equalizer
US5225922A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1991 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | Nov 21, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S2301/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Increasing the capacity of an existing lightwave transmission system can be accomplished by either increasing the bit rate or adding wavelength-multiplexed channels. Recent advances in erbium-doped fiber amplifier technology make the wavelength division multiplexed option particularly attractive. Unfortunately, because of nonuniform wavelength-dependent gain profile and saturation characteristic of erbium-doped fiber amplifiers, each channel of a wavelength-multiplexed system will experience a different optical gain which, in turn, can result in an excessive bit-error-rate performance in some channels. This invention is directed toward processing apparatus which selectively equalizes the optical gain or the optical signal-to-noise ratios of the channels of a wavelength-multiplexed optical transmission system. The output powers and the signal-to-noise ratios are selectively equalized by adjusting the optical input signal powers. With this invention, wavelength-multiplexed channels can be added to an existing optical fiber transmission system without requiring new optical components, upgrades or adjustments at intermediate amplifier sites.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.