| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a modulation unit for a quantum communication system.SOLUTION: A modulation unit includes an optical element configured to bring about a delay between photons of different polarization mode, and a phase modulator. The optical element has a birefringent optical material, and the birefringent optical material allows transmission of photons in first polarization mode and second polarization mode. The optical path length of a photon propagating in the first polarization mode is different from the optical path length of a photon propagating in the second polarization mode. A photon in the first polarization mode has orthogonal polarization for the photon in the second polarization mode. The phase modulator is configured to apply a further phase difference between a photon in the first polarization mode and a photon in the second polarization mode passing through the modulation unit.</p> |
