Variable Oblique Incidence for Tunability in a Two-dimensional Photonic Crystal Guided-Wave Filter

In this paper, the tuning mechanism for a twodimensional (2-D) guided-wave photonic-crystal (PhC) filter obtained by varying the angle-of-incidence in the waveguide plane is demonstrated. Modeling and design of the filter have been carried out by using the Bloch–Floquet formalism. The device shows a resonance wavelength at 1550 nm for the p = 30 order at normal incidence. The free spectral range (FSR) is about 38 nm and can be spanned with an in-plane angle of incidence θ ranging from 0◦ to 14◦. The full width at half maximum (FWHM) is in the range 0.14–0.18 nm. The filter performance is suitable for 50-GHz dense-wavelength-division-multiplexing (DWDM) systems and shows that variable oblique incidence can be exploited as a tuning mechanism.