We experimentally demonstrate a 10 Mbit/s free-space quantum communication link using data encoding on orthogonal Laguerre–Gaussian (LG) modes with the same azimuthal index but different radial indices. Data encoding on two ${\mathrm{LG}}_{\ell p}$ modes (i.e., for $\ell =0$, we encode [“0”, “1”] as [$p=0$, $p=1$], and for $\ell =1$, we encode [“0”, “1”] as [$p=0$, $p=1$]) is demonstrated by employing directly modulated laser diodes and helical phase holograms. The quantum symbol error rate (QSER) of $<5\%$ is achieved at an encoding rate of 10 Mbit/s. Moreover, the influence of the circle radius ($R$) of the receiver phase pattern on registered photon rates and QSERs is investigated. Our results show that a receiver phase pattern whose $R$ does not match the beam size of the LG modes would induce higher cross talk between the two encoded quantum branches.

中文翻译：

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通过在具有不同径向索引的两个Laguerre-Gaussian模式下对数据进行编码来演示10 Mbit / s量子通信链路

我们通过实验证明了在正交Laguerre-Gaussian（LG）模式下使用具有相同方位角索引但径向索引不同的数据编码的10 Mbit / s自由空间量子通信链路。数据编码上两个${\mathrm{LG}}_{\ell p}$ 模式（即 $\ell =0$，我们将[“ 0”，“ 1”]编码为[$p=0$， $p=\mathrm{1个}$]，并用于 $\ell =\mathrm{1个}$，我们将[“ 0”，“ 1”]编码为[$p=0$， $p=\mathrm{1个}$]）通过使用直接调制的激光二极管和螺旋相位全息图进行演示。的量子符号错误率（QSER）$<5％$以10 Mbit / s的编码速率实现。而且，圆弧半径（$\mathrm{[R}$研究了在注册光子速率和QSERs上的接收器相位模式。我们的结果表明，接收器相位模式的$\mathrm{[R}$ 如果不匹配LG模式的光束大小，则会在两个编码的量子分支之间引起较高的串扰。