All-optical analog to electromagnetically induced transparency effects for multiple wavelengths in a silicon photonic crystal coupled cavity system

We design and theoretically study the all-optical analog to electromagnetically induced transparency (EIT) effect in a system consisting of two heterojunction cavities and one waveguide in a silicon photonic crystal slab with a triangular lattice. Multiple modes with a high Qint/Qc ratio are found in both cavities. By tuning the resonance difference and phase difference between cavities, EIT-like phenomena for two modes at different wavelengths are found. Our analyses show that optical delays of 0.34 and 0.20 ns are realized for each optical EIT peak, thereby benefiting further research and applications, such as multiple-wavelength switches, optical buffer devices, and signal processing. The relationship between the characteristics of the optical EIT-like peak and several parameters is investigated, and the results can provide a reference for future experiments. The 3D finite-difference time-domain method is used to analyze the field distribution in the process.