Realization of fast speed information processing device for communication and its application. In this paper, optical device with the 2D Photonic Crystals is proposed. The photonic DWDM (Dense Wavelength Division Multiplexing) demultiplexer uses the concept of splitting the incoming signals to the defined network. The work proposes a integrated 4 channel Photonic crystal DWDM demultiplexer. One side of the demultiplexer is designed to support 100 GHz and another side of demultiplexer is supported to drop 200 GHz. The proposed demultiplexer is also designed to support drop desired wavelength in C and L band. The Photonic optical AND gate is designed using constructive interfernce. The proposed device support with high bit rate and contrast ratio of 11.76 Tbps and 11 dB. The size of the proposed device is 230.64 µm2 and results of the proposed device is best suitable for Photonic Integrated Circuits (PIC) © 2020, Springer Nature Singapore Pte Ltd.