Digital data transmission system by coherent light wave modulation
US4723310A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1984 |
| Grant date | Feb 2, 1988 |
| Priority date | — |
| Expiry date | Nov 9, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/148
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A digital data transmission system by modulating a coherent light wave is provided using modulation of the MSFK type with N frequencies for modulating the light wave. The transmitter comprises a coherent light source, a modulator, an output optical means and an MSFK modulation signal generator. The receiver comprises an input optical means, local light wave source and a heterodyne mixer for creating an electric signal of intermediate frequency. A demodulation and detection circuit comprises filtering means for separately selecting the N frequencies before detection. A processing cirucit puts the data back into its initial form. A circuit for compensating for the drift of the light sources is used for preserving lock on to the intermediate frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.