Design of Photonic Crystal All-Optical Analog-to-Digital Using Nonlinear Kerr Effect

This study presents an innovative approach to the design of an optical analog-to-digital converter (OADC) that employs square nonlinear ring resonators. The configuration consists of dielectric silicon rods alongside nonlinear rods fabricated from doped glass, utilizing the Kerr optical effect to realize the intended operational capabilities. The proposed architecture incorporates a nonlinear three-channel demultiplexer along with an optical encoder. The nonlinear demultiplexer transforms the continuous input signal into three distinct quantized levels, while the optical encoder produces two-bit binary codes corresponding to the demultiplexer's output channel. The performance of this optical analog-to-digital converter (OADC) has been evaluated through plane wave expansion (PWE) and finite difference time domain (FDTD) methodologies. Results demonstrate that the OADC exhibits a compact footprint of 324 µm² and achieves a sampling rate of 125 GS/s, significantly exceeding the capabilities of traditional analog-to-digital converter designs.