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Communication system and communication method using the same

外国特許コード F110003745
整理番号 E06203WO
掲載日 2011年7月4日
出願国 アメリカ合衆国
出願番号 58103704
公報番号 20070110242
公報番号 07974540
出願日 平成18年12月28日(2006.12.28)
公報発行日 平成19年5月17日(2007.5.17)
公報発行日 平成23年7月5日(2011.7.5)
国際出願番号 PCT/JP2004/017681
国際公開番号 WO2005/053219
国際出願日 平成16年11月29日(2004.11.29)
国際公開日 平成17年6月9日(2005.6.9)
  • 特願2003-398491 (2003.11.28) JP
  • 特願2004-335228 (2004.11.19) JP
発明の名称 (英語) Communication system and communication method using the same
発明の概要(英語) A communication system capable of employing polarization-dependent phase modulators with a reversing configuration that preserves security against disturbance of a polarization state at a transmission path but without using Faraday mirrors and a communication method using the same are provided.A quantum cryptography system of the present invention includes a first station 1, a transmission path 2, and a second station 3. The first station 1 has means for emitting time-divided optical pulses into the transmission path 2 and measuring a phase difference between the optical pulses returning from the transmission path 2. The transmission path 2 is a medium of light. The second station 3 has means for reversing traveling directions of the optical pulses, means for producing a phase difference, corresponding to a random number bit value to be transmitted, between the time-divided optical pulses, means for splitting the entering optical pulse into orthogonally polarized components and producing a 180-degree phase difference therebetween, means for rotating each polarization direction by 90 degrees, means for eliminating a component resulting from a deviation from the polarization rotation angle of 90 degrees, and means for attenuating optical pulse intensity to include no more than 1 photon per bit.
  • 発明者/出願人(英語)
  • Tomita, Akihisa; Tsukuba [JP]
  • Nakamura, Kazuo; Tokyo [JP]
  • Tajima, Akio; Tokyo [JP]
  • Tanaka, Akihiro; Tokyo [JP]
  • Nanbu, Yoshihiro; Tokyo [JP]
  • Suzuki, Shuuji; Tokyo [JP]
  • Takeuchi, Takeshi; Tokyo [JP]
  • Maeda, Wakako; Tokyo [JP]
  • Takahashi, Seigo; Tokyo [JP]
  • Japan Science and Technology Agency, Kawaguchi-shi [JP]
  • NEC Corporation, Tokyo [JP]
  • 398/152
  • 380/277
  • 380/278
  • 385/1
  • 385/2
  • 385/3
  • 385/11
  • 385/24
  • 398/140
  • 359/485
  • 359/502
参考情報 (研究プロジェクト等) ERATO IMAI Quantum Computation and Information AREA