Abstract
        This study aims to design and simulate a two-dimensional all-optical nonlinear analog-to-digital converter (ADC) using a set 
of power splitters, U-shaped, add/drop, and bus waveguides. In this work, the transmission and wavelength of output ports 
are managed by the length of the waveguide, number of coupling rods, nonlinear effects, and also the radius and refractive 
index of coupling and scattering rods. In this design, according to the nonlinear effects and the controlling parameters we 
can approximate the logic 0 and 1 states using the power transmission at the output ports. The finite-difference time-domain 
(FDTD) method is employed to investigate the transmission characteristics of the device for a variety of refractive indices.
The output efficiency of the 2-bit converter is estimated as 80% and the footprint of the proposed structure is obtained to be 
741 µm2
. The minimum quantized pulse width of the proposed structure is 0.7 ps. Considering this time delay, the 
conversion rate is estimated as much as 1430 Gb/s.
        Keywords
        Analog-to-digital converter (ADC), Silicon photonic crystal, Interference, Nonlinear effect.
        Citation
        MASOUD MOHAMMADI, RAHIM KARAMI, MAHMOUD SEIFOORI, SAEED OLYAEE, Ultra-compact 2-bit analog-to-digital convertor based on  silicon photonic crystal waveguide, Optoelectronics and Advanced Materials - Rapid Communications, 18, 1-2, January-February 2024, pp.8-15 (2024).
        Submitted at: June 14, 2023
 
        Accepted at: Feb. 9, 2024