Sharp edge wavelength filters utilizing multilayer photonic crystals.

A novel configuration of dielectric multilayer wavelength filters for enabling sharp cut-off characteristics is proposed. By applying perturbations to the multilayer structures such as corrugation or lateral film isolation, deep optical stopbands can be created as a result of the coupling between the obliquely and horizontally propagating light waves. Numerical simulation by FDTD revealed that the proposed structure had approximately two to three times larger decay constants than that of unmodulated flat multilayer.