ABSTRACT

Optical filters can selectively permit the propagation of the signal light with a certain frequency, and forbid the propagation of other signal lights with different frequencies. Moreover, optical filters with a size of nano/micrometer scale play a very important role in the integrated photonic circuits, optical interconnection networks, and wavelength division multiplexing systems. Photonic crystals are perfect basis for the realization of future integrated photonic devices due to their unique properties of controlling the propagation states of photons. Therefore, much attention has been paid to the realization of optical filter based on photonic crystals. The optical channel or pass band of a tunable photonic crystal can be tuned by adjusting the external parameters. Therefore, in practice, tunable photonic crystal filter can find wider and greater applications. 5.1 Configuration of Photonic Crystal Filter

The photonic bandgap effect and the photon localization effect are the essential basis for the realization of photonic crystal filter. Owing to the strong Bragg scattering and strong interference effect, photonic crystal can prohibit the transmission of electromagnetic waves whose frequencies drop in the photonic bandgap.