New design of all-optical multi-channel wavelength division multiplexer based on 2D PC waveguide structures with square rods

A new all-optical multi-channel wavelength division multiplexer (WDM) based on a two-dimensional photonic crystal (2D PC) waveguide structure with square rods, which has the output flat-top bands was proposed. The bandpass WDM creates an appropriate folded structure that possesses resonance frequencies with the flap-top output bands, high transmission efficiency and less crosstalk within the photonic crystal bandgap region. This numerical results show that the proposed PC multi-channel WDM can filter out certain wavelengths in the optical communication region with flat-top output bands. This performance of the proposed PC waveguide structure does not affect by external environment factors because of the flap-top output bands. We proposed the seven-channel PC WDM optical waveguide structure and it also achieves the CWDM specifications which are defined by ITU-T Recommendation G. 649.2.