An Optimized Photonic Crystal Waveguide with Shifted Air Holes to Manipulate Dispersion and Generate Slow Light

The study of the dispersion characteristics of photonic crystal waveguides (PCW) and optimization of their structural parameters is crucial for achieving slow light with a high group index while mitigating group velocity dispersion (GVD). This balance is essential for enhancing the performance and applicability of optical devices utilizing slow light phenomena. In this paper, the structural parameters, such as the shape, size, and position of air holes of the waveguide, are investigated for their impact on dispersion characteristics of Transverse Electric (TE) even mode of propagation in PCWs using the Finite Element Method (FEM). By systematically varying the structural parameters and observing their effects on dispersion, the PCW design can be tailored to achieve specific slow light behavior while minimizing undesired dispersion effects. This optimization process facilitates the development of PCW with improved performance and broader bandwidth, enabling a range of practical applications in optical communication, sensing, and signal processing. An optimized structure providing the slow light with value of group index ng = 18.5 and normalized delay bandwidth product (NDBP) of 0.2410 is obtained using the outcomes of the structural manipulation technique of shifting the air holes vertically and horizontally.