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Quantum cryptography using balanced homodyne detection

T. Hirano·T. Konishi·R. Namiki
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Abstract

We report an experimental quantum key distribution that utilizes balanced homodyne detection, instead of photon counting, to detect weak pulses of coherent light. Although our scheme inherently has a finite error rate, it allows high-efficiency detection and quantum state measurement of the transmitted light using only conventional devices at room temperature. When the average photon number was 0.1, an error rate of 0.08 and "effective" quantum efficiency of 0.76 were obtained.

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T. Hirano, T. Konishi, R. Namiki. 2010-09-10. Quantum cryptography using balanced homodyne detection. https://doi.org/10.1103/physreva.68.042331

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