Apparatus and method for adjusting the phase-modulator's modulating signal time reference in a quantum-key-distribution system
US12401426B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 2022 |
| Grant date | Aug 26, 2025 |
| Priority date | — |
| Expiry date | Sep 20, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L9/0858
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present disclosure relates to the field Quantum Key distribution (QKD) and discloses an apparatus (100) and method (300) for adjusting the phase modulator's modulating signal time reference in a phase-based QKD system. The QKD system comprises a pulse generator (10) that generates optical pulses and a phase modulator (20) that modulates the phase of each of the pulses. The apparatus (100) comprises abeam splitter/tap (112), a 1-bit delay interferometer (110), two photodetectors (106,108), and a processing device (104). The splitter feeds the phase modulated optical pulses to the interferometer (110). Two photo detectors are connected to the constructive and destructive output legs (110a,110b) of the interferometer (110). The photo detectors' output are then converted to digital signals and fed to the processing device (104). The processing device (104) measures the average power at both the legs of the interferometer (110) to detect delay between optical signal and modulating signal and adjusts the delay to accurately align the phase modulator (20) with the pulse generator (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.