All-optical quantization and coding scheme for ultrafast analog-to-digital conversion exploiting polarization switches based on nonlinear polarization rotation in semiconductor optical amplifiers

A novel all-optical quantization and coding scheme for ultrafast analog-to-digital (A/D) conversion exploiting polarization switches (PSWs) based on nonlinear polarization rotation (NPR) in semiconductor optical amplifiers (SOAs) is proposed. In addition, a theoretical model for the polarization switch based on NPR is presented. Through cascading two PSWs, a 2-period transfer function for 3-bit long all-optical quantization and coding is realized numerically for the first time to the authors' knowledge. The effective number of bits (ENOB), the limitation of bandwidth and conversion speed and the scalability are also investigated. The proposed all-optical quantization and coding scheme, combined with existing all-optical sampling techniques, will enable ultrafast A/D conversion at operating speed of hundreds of Gs/s with at least 3 bit resolution, and allows low optical power requirements, photonic integration, and easy scalability.