Patent · US Expired

Quantum cryptography system for a secure transmission of random keys using a polarization setting method

US6748081B1 · kind B1 · utility

13Cited by

4References

5Claims

0Family size

Assignee

DEUTSCHE TELEKOM AG · DE

Inventors

Wolfgang Dultz · Frankfurt am Main, DE
Heidrun Schmitzer · Grünhain, DE
Leonid A. Beresnev · Dayton, US
Eric Hildebrandt · Frankfurt, DE

Key dates

Filing date	Jul 20, 1999
Grant date	Jun 8, 2004
Priority date	—
Expiry date	Jul 20, 2019

Classification

Technology area (CPC G)Physics
CPC primaryG02F1/13
WIPO fieldBasic materials chemistry
WIPO sectorChemistry

Abstract

A quantum cryptography system using electrooptical liquid crystal modulators which change the polarization and which are designed as electrically rotatable retardation plates whose two birefringent axes are rotated by the applied electrical field around an angle &thgr; which depends on the strength of this field. A &lgr;/2 retardation plate rotates the elliptically polarized light striking the plate around an angle 2&thgr; at speeds in the microsecond range. The quantum cryptography system can be used for interception-proof data transmission over transmission links that are accessible to the public.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.