Secure fiber optic data transmission system
US4435850A · kind A · utility
20Cited by
2References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1982 |
| Grant date | Mar 6, 1984 |
| Priority date | — |
| Expiry date | Feb 16, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/065
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A fiber optic data transmission system is protected against external physical intrusion by obscuring the data in the natural quantum noise and then limiting access to the intruder by means of an optical power alarm. This is accomplished by modulating the data on a very large predetermined average optical power with a very small modulation index and then providing an alarm arrangement which is responsive to the received optical energy to activate an alarm means and to deactivate its associated transmitting arrangement when the received optical energy has an amplitude outside of a given amplitude region.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.