Polarization-dependent tuning of Bragg reflection enabled through tilted subwavelength grating waveguide Bragg gratings

We propose and demonstrate experimentally tilted subwave-length 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 trans-verse magnetic (TM) mode remains almost unchanged. In particular, for tilting angles of 5 degrees and 30 degrees, 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 integratedWBGdevices. (C) 2021 Optical Society of America