Design and test of optical payload for polarization encoded QKD for nanosatellites
Design and test of optical payload for polarization encoded QKD for nanosatellites
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DOI：
10.1117/12.2645103
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发表时间：
2022-11
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影响因子：
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通讯作者：
Jaya Sagar;E. Hastings;Peide Zhang;Milan Stefko;D. Lowndes;D. Oi;J. Rarity;S. Joshi
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文献类型：
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作者：
Jaya Sagar;E. Hastings;Peide Zhang;Milan Stefko;D. Lowndes;D. Oi;J. Rarity;S. Joshi
基于卫星的低地球轨道（LEO）量子密钥分发（QKD）是目前唯一可行的跨越数千公里的技术。由于卫星的典型开销持续几分钟，因此增加信号速率以最大化密钥长度至关重要。对于将在两年内发射的QUARC CubeSat使命，我们正在设计一个双波长、弱相干脉冲诱饵态班尼特-巴纳德'84（WCP DS BB 84）QKD源。光学有效载荷设计在一个12×9× 5cm 3的定制铝外壳中。离散变量QKD源由两个对称源组成，工作在785 nm和808 nm。激光二极管被固定以分别产生水平、垂直、对角和反对角（H、V、D、A）偏振，这些偏振被组合并衰减到0.3和0.5光子/脉冲的平均光子数。我们通过对输出光束进行空间模式滤波并描述其光谱和时间特性，确保源对大多数边信道攻击是安全的。源的消光比对固有量子比特错误率（QBER）的贡献为0.817± 0.001%。该源工作在200 MHz，这足以提供每秒几千比特的安全密钥速率，尽管自由空间信道中估计有40 dB的损耗。
Satellite based Quantum Key Distribution (QKD) in Low Earth Orbit (LEO) is currently the only viable technology to span thousands of kilometres. Since the typical overhead pass of a satellite lasts for a few minutes, it is crucial to increase the the signal rate to maximise the secret key length. For the QUARC CubeSat mission due to be launched within two years, we are designing a dual wavelength, weak-coherent-pulse decoy-state Bennett- Brassard ’84 (WCP DS BB84) QKD source. The optical payload is designed in a 12×9×5cm3 bespoke aluminium casing. The Discrete Variable QKD Source consists of two symmetric sources operating at 785 nm and 808 nm. The laser diodes are fixed to produce Horizontal,Vertical, Diagonal, and Anti-diagonal (H,V,D,A) polarisation respectively, which are combined and attenuated to a mean photon number of 0.3 and 0.5 photons/pulse. We ensure that the source is secure against most side channel attacks by spatially mode filtering the output beam and characterising their spectral and temporal characterstics. The extinction ratio of the source contributes to the intrinsic Qubit Error Rate(QBER) with 0.817±0.001%. This source operates at 200MHz, which is enough to provide secure key rates of a few kilo bits per second despite 40 dB of estimated loss in the free space channel.1