Polarization rotation Bragg grating using Si waveguide with top surface groove grating and terrace

Abstract

We report a silicon-waveguide-type polarization rotation Bragg grating with high diffraction efficiency to be used in a wavelength filter. An antisymmetric grating structure formed on the top surface of the waveguide with a terrace is used to generate polarization rotation Bragg diffraction. The finite difference time domain method is used to simulate the device. We found that introducing a side terrace of 25 to 75 nm can attain a high diffraction efficiency. The diffraction efficiency can be more than 20% larger when using this structure. A 300-nm-thick waveguide used in foundries is beneficial for fabricating a device showing large diffraction and main-subpeak separation.

Polarization insensitive silicon waveguide wavelength filter using polarization rotator and mode conversion Bragg grating with resonator cavity

“…9,10) We and others have been studying a polarization insensitive wavelength filter using polarization rotator devices. [11][12][13][14][15] Polarization rotation Bragg grating can attain a polarization insensitive wavelength filtering. Introducing the resonator cavity to the Bragg grating, a narrow wavelength peak can be obtained by relatively short device length.…”