QKD system with common-mode dithering
US8059964B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 20, 2007 |
| Grant date | Nov 15, 2011 |
| Priority date | — |
| Expiry date | Sep 2, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/70
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A QKD system (10) having two QKD stations (Alice and Bob) optically coupled by an optical fiber link (FL), wherein Bob includes a variable timing delay arranged between Bob's controller (CB) and modulator (MB) or detector unit (40). A set-up and calibration procedure is performed wherein delay DL2 is adjusted until the timings for the modulator and detector unit (TSB and TS42, respectively) are established. Delay DL2 is then fixed so that the detector unit and modulator operate in a common timing mode that is not changed if the synchronization signal is changed. The timing TSS of the synchronization (sync) signals (SS) sent from Alice to Bob is adjusted to arrive at optimum system performance. Once the QKD system is in operation, because the sync signal can drift, the sync signal timing TSS is dithered maintain optimum QKD system performance. Since the modulator and detector unit timing is tied together, dithering the sync signal also dithers the modulator and detector unit together in a “common mode,” rather than varying the timing of each of these elements separately.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.