A novel design for 2-bit optical analog to digital (A/D) converter based on nonlinear ring resonators in the photonic crystal structure

In this paper, a new configuration for full optical analog to digital convertor (OADC) based on nonlinear materials has been proposed. This structure is the combination of two main parts; Quantization block, followed by an optical coder. Sampling and quantizing have been performed at central wavelength ʎ = 1550 nm by three ring resonators which are filled by nonlinear material AlGaAs with linear refractive index of n1=1.4 and Kerr index of n2=1.5×10−17m2∕W. A pillar-based hexagonal lattice of a 2DPhC which is made of linear material Silicon with nSi=3.4 have been implemented in the air background. Four ring resonators made of GaN which are located in optical coder are able to reduce the loss and improve the transmission efficiency. The performance of the OADC structure is simulated by means of finite difference time domain (FDTD) method. The proposed structure is able to support maximum sampling rate up to 220 GS/s and total footprint is about 777.52μm2. Resolution Sampling Rate Product is 880 KS.