Frequency Division Multiple Access with High Performance Based on Several Defect Resonators According to the Fibonacci Sequence in 1D Photonic Star Waveguide Structure

In this paper, we give an analytical demonstration of the possibility to realize a simple photonic multichannel tunable filter based on electromagnetically induced transparency (EIT) resonances. On one hand, we present a simple photonic device consisting of multiple grafted resonators at the same site; the resonator lengths depend on each other following the Fibonacci sequence. We have proposed this simple device to obtain EIT type resonances that are situated between two transmission zeros because each resonator induces its own transmission zero. The quality factor of these EIT resonances depends on the difference between the resonator lengths. On the other hand, we investigate the propagation of electromagnetic waves in one-dimensional perfect star waveguides (SWGs) structure composed of the periodicity of segments and grafted in its extremity by a finite number of symmetric resonators. This perfect star waveguide structure presents passbands separated by large bandgaps, these gaps become wider when the number of resonators increases. The insertion of five defect resonators of lengths d_02i = d₀₂ (i = 1–5) located in the same site introduce transmission peaks (defect mode) in the transmission and phase spectrums and in the phase with a high-quality factor (very narrow defect modes) that reach Q = 1 348 700 and therefore our proposed case behaves as a very narrow filter which can select one frequency. To realize a multichannel filter with high performance, we introduce five defect resonators of different lengths d_02i (i = 1–5) according to the Fibonacci sequence in the perfect SWGs. These defect systems can create a large number of defect modes which reach seven defect modes with an important transmission rate and very high-quality factor. With an appropriate choice of the geometrical parameters (the lengths d_02i of the defect resonators), our proposed system can filter a very large number of frequencies (multichannel filter) which can reach ninety-nine frequencies with very high performances.