Symmetry Breaking and Rainbow Trapping: Insights from Coupled Cavity Photonic Crystal Waveguides

This study focuses on achieving rainbow trapping in photonic crystal coupled cavity waveguides via symmetry reduction at the cavity region. Employing both plane wave expansion and finite-difference time domain methods, we explore the impact of integrating an auxiliary rod at varying angles to the primary cavity rod. Our simulations reveal that strategic angle variations maximize the group index and group velocity while investigating group velocity dispersion and third order dispersion within the slow light region. Leveraging these results, we demonstrate effective rainbow trapping by manipulating the auxiliary rod angles in photonic crystal coupled cavity waveguides. Our results have encouraging implications for optical buffering, multiplexing, demultiplexing, advanced time-domain and spatial signal-processing.