论文标题
未来地球同步链接的量子限制光学时间传输
Quantum-limited optical time transfer for future geosynchronous links
论文作者
论文摘要
光学时间传输和光学时钟的组合打开了大规模自由空间网络的可能性，这些自由空间网络连接了基于地面的光钟和未来的空间光钟。这样的网络有望更好地测试一般相对论，暗物质搜索和重力波检测。将光学时钟连接到遥远的卫星的能力可以实现基于空间的长基线干涉法（VLBI），高级卫星导航，基于时钟的测量线，并改善了洲际时间传播。到目前为止，只有光学时钟才能推向量子限制的性能。相比之下，光学时间传输尚未以接收光子的数量设置的类似量子限制进行操作。在这里，我们以接近量子限制的采集和计时的时间转移，收到的功率比以前的方法低10,000倍。夏威夷山顶之间的300公里以上，发射的力量低至40 $μ$ W，遥远的时间标准被同步到320个attoseconds。这种几乎量子限制的操作对于光子很少而扩增的长距离自由空间链路至关重要 - 在4.0 mW传输功率时，该方法可以支持102 dB的链接损失，足以足以使将来的时间传输到地球同步轨道。
The combination of optical time transfer and optical clocks opens up the possibility of large-scale free-space networks that connect both ground-based optical clocks and future space-based optical clocks. Such networks promise better tests of general relativity, dark matter searches, and gravitational wave detection. The ability to connect optical clocks to a distant satellite could enable space-based very long baseline interferometry (VLBI), advanced satellite navigation, clock-based geodesy, and thousand-fold improvements in intercontinental time dissemination. Thus far, only optical clocks have pushed towards quantum-limited performance. In contrast, optical time transfer has not operated at the analogous quantum limit set by the number of received photons. Here, we demonstrate time transfer with near quantum-limited acquisition and timing at 10,000 times lower received power than previous approaches. Over 300 km between mountaintops in Hawaii with launched powers as low as 40 $μ$W, distant timescales are synchronized to 320 attoseconds. This nearly quantum-limited operation is critical for long-distance free-space links where photons are few and amplification costly -- at 4.0 mW transmit power, this approach can support 102 dB link loss, more than sufficient for future time transfer to geosynchronous orbits.
