Highly efficient multiplexer demultiplexer based on liquid crystal channels

A novel design of multiplexer-demultiplexer (MUX-DEMUX) based on channel waveguide on silicon dioxide (SiO2) is introduced and analyzed. The suggested structure consists of two neighboring channels infiltrated with nematic liquid crystal (NLC) material of type E7. The two channels are etched in the SiO2 substrate. The electro-optic effect of the NLC is used to control the waveguide propagation condition using an external electric field. Additionally, a plasmonic wire is inserted between the two waveguides to enhance the suggested MUX-DEMUX in terms of compactness. The modal analysis of the y-polarized modes supported by the NLC MUX-DEMUX is carried out using full-vectorial finitedifference method (FVFDM). Further, the propagation characteristics through the reported design are obtained using full vectorial finite difference beam propagation method (FVFD-BPM). The design parameters of the NLC MUX-DEMUX have been studied to obtain an efficient waveguide coupling with a short device length. Moreover, the NLC MUXDEMUX has a compact device length of 1296 μm. The numerical results reveal that the reported MUX-DEMUX has a small insertion loss of 8x10-6 dB with a good crosstalk better than -37 dB and -30 dB at the studied wavelengths of 1.3 μm and 1.55 μm, respectively. To the best of the authors’ knowledge, it is the first time to introduce a MUX-DEMUX based on channel on SiO2 platform with a simple design and broadband operation.