Opt Lett. 2018 Jul 15;43(14):3200-3203. doi: 10.1364/OL.43.003200.
Efficient light coupling to integrated photonic devices is of key importance to a wide variety of applications. "Inverse nanotapers" are widely used, in which the waveguide width is reduced to match an incident mode. Here, we demonstrate novel "double inverse" tapers, in which we reduce both the waveguide height and width. We demonstrate >45% chip-through coupling efficiency for both the transverse electric and transverse magnetic polarizations in SiN tapers of >500 nm width, in comparison to regular inverse tapers that necessitate <100 nm width. The double inverse tapers show polarization-independent coupling and allow the fabrication using photolithography, relevant for applications at near-infrared and visible wavelengths, e.g., supercontinuum and soliton microcomb generation.
高效的光耦合到集成光子器件对于各种应用都非常重要。“反向纳米锥”被广泛应用，其中波导的宽度被减小以匹配入射模式。在这里，我们展示了新颖的“双反向”锥形结构，其中我们同时减小了波导的高度和宽度。我们在 SiN 锥形结构中展示了>500nm 宽度的横向电场和横向磁场偏振的>45%的芯片穿透耦合效率，而常规的反向锥形结构则需要<100nm 的宽度。双反向锥形结构表现出偏振无关的耦合，并且允许使用光刻技术进行制造，这对于近红外和可见光波长的应用（例如超连续谱和孤子微梳产生）非常重要。
