Optical fiber interferometer with relaxed loop tolerance and QKD system using the same
US7254295B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 2005 |
| Grant date | Aug 7, 2007 |
| Priority date | — |
| Expiry date | Apr 11, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/2861
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An optical fiber interferometer (10) with relaxed loop tolerance, and a quantum key distribution (QKD) system (200) using same is disclosed. The interferometer includes two optical fiber loops (LP1 and LP2). The loops have an optical path length (OPL) difference between them. A polarization-maintaining (PM) optical fiber section (60) of length (L60) and having fast and slow optical axes (AF and AS) optically couples the two loops. The length and fast-slow axis orientation is selected to introduce a time delay (ΔT1-2) between orthogonally polarized optical pulses traveling therethrough that compensates for the OPL difference. This allows for drastically relaxed tolerances when making the loops, leading to easier and more cost-effective manufacturing of the interferometer as well as related devices such as a optical-fiber-based QKD system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.