Open AccessBandpass filters based on phase-shifted photonic crystal waveguide gratings
Author(s) -
Chao Chen,
Xuechun Li,
Hanhui Li,
Kun Xu,
Jihuai Wu,
JT Lin
Publication year - 2007
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.011278
Subject(s) - optics , band pass filter , photonic crystal , materials science , waveguide , finite difference time domain method , insertion loss , optical filter , wavelength division multiplexing , chebyshev filter , photonic integrated circuit , phase (matter) , wavelength , physics , electrical engineering , quantum mechanics , engineering
In this paper, a bandpass transmission filter realized in phase-shifted waveguide gratings based on photonic crystals (PCs) is proposed. Phase-shift regions each composed of one period of photonic crystal (PC) waveguide are incorporated into PC waveguide gratings. The magnitudes of the phase-shifts are modified by involving small changes in the size of the border rods in the phase-shift regions. Using standard coupled-mode theory and finite-difference time-domain (FDTD) method, we show that by properly choosing the magnitudes of phase-shifts and the lengths of waveguide gratings, a flat-top and sharp roll-off response with a narrow bandwidth is theoretically and numerically achieved by the designed filter. A further analysis shows that the center frequency of the transmission band can be changed by altering the magnitude of the phase-shift and the response performance exhibits relaxed sensitivity to the phase-shift variation. As a specific application, we theoretically demonstrate a third-order Chebyshev bandpass filter based on compound phase-shifted PC waveguide gratings. The filter performance is suitable for dense wavelength-division-multiplexed (DWDM) optical communication systems with a channel spacing of 100-GHz.