Design and analysis of an optical demultiplexer based on Bragg grating using plasmonic waveguides and defects

Abstract

An infrared multi-channel optical de/multiplexer consisting of plasmonic waveguides is designed and numerically investigated. The proposed device applies the advantages of surface plasmon polaritons and the Bragg filter waveguides to realize the multi/demulti-plexing function. In this work, the application of single tuned defect in the middle of Bragg grating and a tuned nano-cavity for each channel in the proposed structures present some novel results as demultiplexers operation. According to the simulation results, the transmittances of the output channels reach up to 50 % at the desired wavelengths. Thereafter, the geometries of the proposed structures have been optimized to enhance the functional characteristics. Within the channels, a wavelength spacing of 130 nm and a crosstalk around − 22.6 dB is obtained for the optimized four-channel structure in the desired operating wavelength range. In addition to presenting an innovative structure in this article, the performance parameters such as crosstalk and transmittance are at higher levels compared to those of the devices presented in similar works. The simple fabrication process, high efficiency, narrow passband and wide operating range make the proposed micro device a suitable choice for several applications in optical telecommunications.