System for optically transmitting digital communications over an optical fiber with dispersion at the operating wavelength
US5371625A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1993 |
| Grant date | Dec 6, 1994 |
| Priority date | — |
| Expiry date | Jan 29, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/25137
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
When digital signals are transmitted over optical fibers (3), which have a considerable chromatic dispersion at the wavelength being used, the length of the transmission path is very limited when the digital signal to be transmitted is converted into an optical signal by means of intensity modulation. If frequency modulation (also called FSK=Frequency Shift Keying) is used instead of the intensity modulation, the bridgeable path can be greatly increased, but requires a suitable optical receiver at the receiving end. The invention utilizes a simple optical receiver (4), which is not sensitive to frequency modulation, but to intensity modulation. This is possible, because an intensity variation is created, due to the chromatic dispersion of the optical fiber (3) and the resulting running time differences of signal portions at different wavelengths (.lambda..sub.0, .lambda..sub.1) from the initial frequency modulation during the transmission over the optical fiber (3), which process is contained in the digital signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.