Kang Jian, Cheng Zhenzhou, Zhou Wen, Xiao Ting-Hui, Gopalakrisna Kimmy-Laure, Takenaka Mitsuru, Tsang Hon Ki, Goda Keisuke
Opt Lett. 2017 Jun 1;42(11):2094-2097. doi: 10.1364/OL.42.002094.
We present a focusing subwavelength grating (SWG) for efficient coupling of mid-infrared (mid-IR) light into suspended membrane Ge photonic integrated circuits (PICs) that enable mid-IR applications in the entire fingerprint region. By virtue of their wide spectral transparency window and air-cladding device configuration, the suspended membrane Ge PICs are expected to be effective for mid-IR applications over the spectral region covering from 2 to 15 μm. Specifically, we demonstrate the maximum coupling efficiency of -11 dB with a 1-dB bandwidth of ∼58 nm at the SWG's center wavelength of 2.37 μm. Our focusing SWG is expected to advance the development of on-chip long-wavelength mid-IR applications such as biochemical sensing, thermal imaging, and nonlinear optics in the fingerprint region.
我们展示了一种聚焦亚波长光栅（SWG），用于将中红外（mid-IR）光高效耦合到悬浮膜锗光子集成电路（PIC）中，从而实现整个指纹区域的中红外应用。凭借其宽光谱透明窗口和空气包层器件结构，悬浮膜锗PIC有望在覆盖2至15μm的光谱区域内有效用于中红外应用。具体而言，我们展示了在SWG中心波长2.37μm处，最大耦合效率为-11dB，1dB带宽约为58nm。我们的聚焦SWG有望推动芯片上长波长中红外应用的发展，如指纹区域的生化传感、热成像和非线性光学。
