Heilmann René, Greganti Chiara, Gräfe Markus, Nolte Stefan, Walther Philip, Szameit Alexander
Appl Opt. 2018 Jan 20;57(3):377-381. doi: 10.1364/AO.57.000377.
The vast development of integrated quantum photonic technology enables the implementation of compact and stable interferometric networks. In particular, laser-written waveguide structures allow for complex 3D circuits and polarization-encoded qubit manipulation. However, the main limitation in the scaling up of integrated quantum devices is the single-photon loss due to mode-profile mismatch when coupling to standard fibers or other optical platforms. Here we demonstrate tapered waveguide structures realized by an adapted femtosecond laser writing technique. We show that coupling to standard single-mode fibers can be enhanced up to 77% while keeping the fabrication effort negligible. This improvement provides an important step for processing multiphoton states on chip.
集成量子光子技术的巨大发展使得紧凑且稳定的干涉网络得以实现。特别是，激光写入波导结构允许构建复杂的三维电路以及进行偏振编码量子比特操控。然而，集成量子器件扩大规模的主要限制在于，当与标准光纤或其他光学平台耦合时，由于模式轮廓失配导致的单光子损耗。在此，我们展示了通过一种适配的飞秒激光写入技术实现的锥形波导结构。我们表明，在将制造工作量保持在可忽略不计的情况下，与标准单模光纤的耦合可增强高达77%。这一改进为在芯片上处理多光子态迈出了重要一步。
