Spin-active optical emitters in silicon carbide are excellent candidates toward the development of scalable quantum technologies. However, efficient photon collection is challenged by undirected emission patterns from optical dipoles, as well as low total internal reflection angles due to the high refractive index of silicon carbide. Based on recent advances with emitters in silicon carbide waveguides, we now demonstrate a comprehensive study of nanophotonic waveguide-to-fiber interfaces in silicon carbide. We find that across a large range of fabrication parameters, our experimental collection efficiencies remain above 90%. Further, by integrating silicon vacancy color centers into these waveguides, we demonstrate an overall photon count rate of 181 kilo-counts per second, which is an order of magnitude higher compared to standard setups. We also quantify the shift of the ground state spin states due to strain fields, which can be introduced by waveguide fabrication techniques. Finally, we show coherent electron spin manipulation with waveguide-integrated emitters with state-of-the-art coherence times of T₂ ∼ 42 μs. The robustness of our methods is very promising for quantum networks based on multiple orchestrated emitters.

中文翻译：

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碳化硅波导光纤接口的精确表征


碳化硅中的自旋活性光学发射器是开发可扩展量子技术的绝佳候选者。然而，有效的光子收集受到光学偶极子的非定向发射模式以及碳化硅的高折射率导致的低全内反射角的挑战。基于碳化硅波导发射器的最新进展，我们现在展示了对碳化硅中纳米光子波导与光纤界面的全面研究。我们发现，在大范围的制造参数下，我们的实验收集效率保持在 90% 以上。此外，通过将硅空位色心集成到这些波导中，我们展示了每秒 181 千计数的总体光子计数率，这比标准设置高了一个数量级。我们还量化了由于应变场引起的基态自旋态的变化，这可以通过波导制造技术引入。最后，我们展示了波导集成发射器的相干电子自旋操纵，其最先进的相干时间为 T ₂ ∼ 42 μs。我们的方法的稳健性对于基于多个协调发射器的量子网络来说非常有前途。