| 摘要 |
<p>QKD receiving apparatus is provided with an alignment-correction system for correcting misalignment of a quantum signal received at an optical port of the apparatus relative to a quantum-signal detector of the receiving apparatus. The alignment-correction system comprises a misalignment measuring subsystem for making multiple different misalignment measures, and a misalignment compensation subsystem for adjusting the relative alignment of the quantum signal and quantum-signal detector in dependence on the misalignment measures made. The misalignment measuring subsystem comprises an alignment-beam source, an alignment-beam detector arrangement, and optical components for guiding an alignment beam from the alignment-beam source to the optical port, and for guiding the alignment beam, after external retro-reflection at a cooperating QKD transmitting apparatus from the optical port to the alignment-beam detector arrangement.</p> |
