Research Projects

This project proposal aims to investigate soliton based nonlinear systems to realize all-optical logic gates based half subtractor, full adder, and full subtractor and quantum gates. For exploring the proposed goal, two different nonlinear systems will be studied, namely (i) multi-core photonic crystal fiber coupler, and (ii) array soliton waveguides. In case of photonic crystal fiber coupler (PCFC), the study involves modeling of diverse symmetric and asymmetric PCFCs employing suitable structural parameters at telecommunication wavelengths. In order to explore the influence of elevated nonlinearity and desired dispersion, an attempt will be made to examine the silica core PCFC and highly nonlinear liquids (chloroform, CS2, toluene, etc.) filled in PCFC cores also designed. From the designed PCFC, the optical parameters necessary to investigate steering characteristics and coupling dynamics will be measured via finite element method (FEM). The numerical investigation of switching characteristics to determine the control signal power will be analyzed using split step Fourier numerical method (SSFM) through the governing coupled nonlinear Schrödinger equations. Next, by applying the apt control signal, extinction ratio calculation for individual output cores with suitable combinations of logic inputs will be analyzed to perform necessary logic operations. From the right combination of logic gates and control signal, the adder, and subtractor functionalities will be implemented. On the other hand, for implementation of the soliton based quantum gates, the array soliton based waveguides will be inspected. This study involves soliton scattering in the presence of different potential setups and rotational operator based rotations involving composite solitons to attain necessary quantum gates. Initial part of the study involves in identifying the right combinations of array soliton and potential setups involving potential wall/well with or without control soliton to observe the necessary scattering outcome. The soliton scattering is analyzed numerically employing iterative power series method through suitable coupled nonlinear Schrödinger equations, namely, Gross-Pitaevskii and Manakov equations. The qubits of the quantum gates are defined by appropriate combination of two-solitons are multi-solitons. Through right protocol, the quantum gate functionality will be delivered. For rotational gates, through rotational operator, the composite solitons will be rotated at certain phase, quantum gates will be realized. The proposal will definitely provide significant insight to understand the variation in the nonlinear optical modes as a function of geometrical asymmetry and their impact on delivering logic function. Additionally, quantum gates that will be implemented based on array soliton wave guides will contribute to the possibility and significant progress in the soliton based quantum computing.