Kamata Mikiya, Baba Toshihiko
Opt Express. 2023 Jul 17;31(15):25245-25252. doi: 10.1364/OE.494105.
We experimentally analyzed the internal reflection and loss of each component in a Si photonics frequency-modulated continuous-wave light detection and ranging (FMCW LiDAR) device using optical frequency domain reflectometry (OFDR) with a spatial resolution of better than 2.5 µm. Sweeping the incident laser wavelength by 120 nm, the reflections and losses of wire waveguides, widened waveguides, and optical switches on the chip were individually revealed. The slow-light grating (SLG) beam scanner, which has a limited working wavelength range, was evaluated with a spatial resolution of >10 µm by narrowing the wavelength sweep range. Consequently, a strong reflection was observed at the transition between the wire waveguide and the SLG, which can be a noise source in the FMCW LiDAR. Additionally, this study showed that the OFDR can be an important analysis tool for Si photonics integrated circuits. To our knowledge, this is the first demonstration, showing that the OFDR can be an important analysis tool for Si photonic integrated circuits.
我们使用空间分辨率优于2.5 µm的光学频域反射仪（OFDR），对硅光子学调频连续波光探测与测距（FMCW LiDAR）设备中各组件的内反射和损耗进行了实验分析。通过将入射激光波长扫描120 nm，分别揭示了芯片上线形波导、加宽波导和光开关的反射和损耗。针对工作波长范围有限的慢光光栅（SLG）光束扫描器，通过缩小波长扫描范围，以大于10 µm的空间分辨率进行了评估。结果，在线形波导和SLG的过渡处观察到强烈反射，这可能成为FMCW LiDAR中的一个噪声源。此外，本研究表明，OFDR可成为硅光子集成电路的重要分析工具。据我们所知，这是首次证明OFDR可成为硅光子集成电路的重要分析工具。
