A Novel 2-Bit Optical Digital-to-Analog Converter Based on Two-Dimensional Photonic Crystals

This paper presents a novel 2-bit optical Digital-to-Analog Converter (DAC) based on two-dimensional photonic crystals, utilizing a unique design to fully exploit optical principles. The proposed structure uses a square lattice of silicon rods in an air background to create a photonic bandgap that blocks the 1.55-micrometer wavelength. The DAC achieves digital-to-analog conversion through careful control of the photonic bandgap and waveguides, providing four distinct output states. Simulations using the Finite-Difference Time-Domain (FDTD) method demonstrate the high accuracy and speed of this design, achieving a switching time of approximately 0.05 picoseconds. Compared to previous works, the proposed DAC offers a significantly smaller size and faster operation, making it suitable for integration into optical circuits and communication systems.