Study on quantum communication using femto-seconds pulses

利用飞秒脉冲进行量子通信的研究

• 批准号: 12640394
• 负责人: HIRANO Takuya
• 金额: $ 2.24万
• 依托单位: Gakusyuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640394/
• 关键词: femtosecond pulse; parametric amplification; squeezed states; guasi-phase matching; quantum communication; quantum teleportation; quantum cryptography; BBO; 超短パルス; フェムト秒; 非線型光学; スクイーズド光; 量子相関

We have achieved the following results.(1) We obtained more than 40% conversion efficiency for the second harmonic generation of a mode-locked YVO_4 laser using a quasi-phase-matched periodically-polled KTiO_4 (PPKTP) crystal.(2) We observed 10% parametric gain using a femtosecond Ti:sapphire laser and β-BaB_2O_4 crystal.(3) We obtained parametric gain of 10.4 dB and -3.2 dB squeezing using a PPKTP crystal.(4) We have developed an optical coupling system using a gradient index micro lens which enables good coupling efficiency for a periodically polled LiNbO_3 waveguide, and observed second harmonic generation.(5) We have developed a balanced homodyne detector based on a commercial amplifier with which we could observe vacuum fluctuations using pulsed local oscillator.(6) We have achieved quantum key distribution over a 1 km optical fiber using pulsed homodyne detection. We show that quantum cryptography based on homodyne detection is secure against individual beam-splitting attack.

我们取得了以下成果。(1)利用准相位匹配的无偏极化KTiO_4（PPKTP）晶体实现了YVO_4锁模激光器的倍频转换，获得了40%以上的转换效率。(2)我们用钛宝石飞秒激光器和β-BaB_2O_4晶体观察到10%的参量增益。(3)用PPKTP晶体获得了10.4dB的参量增益和-3.2dB的压缩。(4)我们研制了一种使用梯度折射率微透镜的光耦合系统，它能使周期性极化铌酸锂波导有良好的耦合效率，并观察到二次谐波的产生。(5)我们研制了一种基于商用放大器的平衡零差探测器，利用脉冲本振观测真空涨落。(6)我们已经实现了量子密钥分配超过1公里的光纤使用脉冲零差检测。我们证明了基于零差检测的量子密码术是安全的，可以抵抗单独的分束攻击。

项目成果

M.Matsuoka and T.Hirano: "Quantum by distribution with a single photon from a squeezed coherent state"Phys. Rev. A. 67, April issue. (2003)

M.Matsuoka 和 T.Hirano：“来自压缩相干态的单个光子的量子分布”Phys。

J.Abe,T.Kuga,T.Hirano,M.Kobayashi,M.Yamanishi: "Widebard squeezing in photon number fluctuations from a high-speed light emitting diode"Optics Express. 7. 215-221 (2000)

J.Abe、T.Kuga、T.Hirano、M.Kobayashi、M.Yamanishi：“Widebard 压缩高速发光二极管的光子数波动”Optics Express。

平野琢也: "パルス光を用いた量子通信実験"応用物理学会誌. 72. 163-168 (2003)

Takuy​​a Hirano：“使用脉冲光的量子通信实验”日本应用物理学会杂志 72. 163-168 (2003)。

平野琢也(分担): "実験物理学講座第9巻レーザー測定「直交スクイーズド光」"丸善. 314(10) (2000)

Takuy​​a Hirano（贡献者）：“实验物理课程第 9 卷激光测量‘正交压缩光’”Maruzen 314(10) (2000)。

M.Matsuoka, T.Hirano: "Quantum key distribution with a single photon from a squeezed coherent state"Phys.Rev.A. 67(1 April issue). (2003)

M.Matsuoka、T.Hirano：“来自压缩相干态的单个光子的量子密钥分布”Phys.Rev.A。