Résumé:
Photonic crystals are periodic dielectric structures, at the wavelength scale, and with high index contrast. In such a medium, the propagation of light exhibits properties, if not exotic, at least surprising. These structures exhibit a unique optical property which is the photonic band gap (PBG) in which no electromagnetic mode can propagate. This BPG is very interesting for several applications in the field of optical telecommunication such as the splitter. Ideally, the splitter should divide the input power equally between the output channels without reflection losses and should be of compact size. In this work, a contribution was made to design power splitters in Y-junctions 1×2, 1×4, and 1×8 based on photonic crystals. These devices play a crucial role in optical telecommunications systems. To improve the performance of these splitters, optimization techniques were proposed. Advanced optimization methods were implemented, such as increasing the radius of the holes in curved areas and adding ring slots. These modifications help minimize losses induced by the bends and junctions of the structures. Our power splitters achieve near perfect transmission (≈ 100%), a relatively wide bandwidth (≈ 3.5%), and remarkable compactness. Compared to our results, previous works have shown lower transmissions (ranging from 86% to 99%) and narrower bandwidths, generally between 1.5% and 3%. Thus, our devices exhibit a transmission improvement of +5% to +15%, and a bandwidth increase of +17% to +133% compared to published works. The power splitters were simulated using RSoftCAD software, employing the Finite-Difference Time-Domain (FDTD) method and the Plane Wave Expansion (PWE) method. A modified T-shaped duplexer, with an area of 272.214 μm², was also proposed. This compact device can be used in integrated optics for applications in FTTH networks.
