Cascaded modulator system and method for QKD
US7447386B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 2006 |
| Grant date | Nov 4, 2008 |
| Priority date | — |
| Expiry date | Feb 23, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L9/0852
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A cascaded modulator system (20) and method for a QKD system (10) is disclosed. The modulator system includes to modulators (M1 and M2) optically coupled in series. A parallel shift register (50) generates two-bit (i.e., binary) voltages (L1, L2). These voltage levels are adjusted by respective voltage adjusters (30-1 and 30-2) to generate weighted voltages (V1, V2) that drive the respective modulators. An electronic delay element (40) that matches the optical delay between modulators provides for modulator timing (gating). The net modulation (MNET) imparted to an optical signal (60) is the sum of the modulations imparted by the modulators. The modulator system provides four possible net modulations based only on binary voltage signals. This makes for faster and more efficient modulation in QKD systems and related optical systems when compared to using quad-level voltage signals to drive a single modulator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.