2-channel MUX-DEMUX for CWDM systems using phase shifted photonic crystals

We tailor the transmission spectrum of 1D photonic crystal to model a 2-channel MUX-DEMUX that exactly fulfils the ITU-T Recommendation G.694.2 for all optic CWDM system. We here incorporate two phase shift regions into the photonic band gap structure through extension of dielectric layers in specific unit cells. These phase shifts open up narrow transmission windows within the photonic band gap of the periodic structure. The amount of introduced phase precisely controls location of the transmission windows. The bandwidth and separation between such windows are governed by the refractive index contrast of the dielectric layers as well as periodicity of the photonic crystal. In addition to simulation of the above ideal module, we also propose a choice of materials for designing a practical one. The simulated results for both of the modules prove the proximal characteristic of the practical module to the ideal one. We use the transfer matrix approach for analysis of transmission characteristics of the resulting structures.