| 摘要 |
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 (LP 1 and LP 2 ). The loops have an optical path length (OPL) difference between them. A polarization-maintaining (PM) optical fiber section ( 60 ) of length (L<SUB>60</SUB>) and having fast and slow optical axes (A<SUB>F </SUB>and A<SUB>S</SUB>) optically couples the two loops. The length and fast-slow axis orientation is selected to introduce a time delay (DeltaT<SUB>1-2</SUB>) 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.
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