2D photonic crystal waveguide
The present example considers a 2D photonic crystal waveguide.
2D photonic crystal waveguide.
The project consists of planar photonic waveguide manufactured in a 2D hexagonal PhC designed for the purpose of the third telecommunication window (M.Notomi, K.Yamada, A.Shinya, J.Takahashi, C.Takahashi, I.Yokohama, "Extremely Large Group-Velocity Dispersion of Line Defect Waveguides in Photonic Crystal Slabs", Physical Review Letters, Vol. 87, No. 25, December 2001, pp.253902-1 - 253902-4). The considered PhC waveguide is manufactured in 200 nm thick Si wafer (n = 3.26) with air cladding. In principle, photonic crystal lattice (a = 390 nm) surrounding waveguide region is composed of the air holes of radius r = 107 nm. TE polarisation (electric field parallel to the wafer plane) exhibits a photonic bandgap (PBG) inside the PhC region around 1.4μm wavelength. Line defect operating as a PhC waveguide is about 6 μm wide and 10 μm long. Due to symmetry of the excited mode and structure, we can reduce the size of the model imposing electric symmetry in the middle of the waveguide width.
2D photonic crystal waveguide project in QW-Editor.
For the purpose of calculating transmission characteristics of the structure, the S-Parameters postprocessing is activated. The S-Parameters postprocessing is set from 166551 GHz to 272538 GHz with a frequency step of 52 GHz.
S-Parameters postprocessing configuration dialogue.
We can notice that the passband is mainly between 1.2 µm and 1.45 µm wavelength, corresponding to the PBG of the applied PhC.
Transmission coefficient in the 1.1 μm ÷ 1.8 μm wavelength range.
For the frequency 207.579 THz, which is in a passband, the field is concentrated near the waveguide region and only a few PhC rows are needed to guide the light properly. The field distribution at 200.299 THz (outside the passband) clearly shows that the wave is strongly attenuated.
Distribution of time-maximum envelope of Hz field component at 207.579 THz.
Distribution of time-maximum envelope of Hz field component at 200.299 THz.