Sun Hao, Chen Lawrence R
Opt Lett. 2021 Mar 15;46(6):1450-1453. doi: 10.1364/OL.420412.
We propose and demonstrate experimentally tilted subwavelength grating (SWG) waveguide Bragg gratings (WBGs). By tilting the SWG segments and optimizing the duty cycle, we can achieve polarization-dependent tuning of the spectral response of the SWG WBG, namely, the spectral response of the fundamental transverse electric (TE) mode shifts toward shorter wavelengths, while that for the transverse magnetic (TM) mode remains almost unchanged. In particular, for tilting angles of 5° and 30°, we can obtain a blueshift in the Bragg wavelength of 7 and 35 nm for the TE mode, while the Bragg wavelength for the TM mode remains within 0.5 nm. The proposed tilted SWG WBGs provide a novel method to manage polarization and/or obtain polarization-dependent wavelength selectivity with integrated WBG devices.
我们提出并通过实验演示了倾斜亚波长光栅（SWG）波导布拉格光栅（WBG）。通过倾斜SWG段并优化占空比，我们可以实现SWG WBG光谱响应的偏振相关调谐，即，基模横向电（TE）模的光谱响应向更短波长移动，而横向磁（TM）模的光谱响应几乎保持不变。特别是，对于5°和30°的倾斜角，我们可以使TE模的布拉格波长分别蓝移7 nm和35 nm，而TM模的布拉格波长保持在0.5 nm以内。所提出的倾斜SWG WBG为集成WBG器件管理偏振和/或获得偏振相关波长选择性提供了一种新方法。
