Tawfik researches are focused on WDM-OPS architectures technology based on wavelength optical converters with fixed, tuneable, parametric, and exchanging. With his supervisors, we have been developed several OPS architectures using FDLs, Tuneable wavelength converters, and recently using wavelength exchangers. All of these architectures are designed to process the data in the optical domain. In our designs, we implement either analytical and/or simulation model for each proposed architecture. Tawfik researches are going in depth in physical behaviours of photonic devices such as photonic crystals and nonlinear fiber optics. We studied the nonlinear haracterizations as three and four wave mixing to implement some optical switch's elements like De/MUX, wavelength converter, wavelength exchanger, and space switch.