Design and analysis of an optical planar waveguide using Invar as core and silicon nitride as cladding layer to control birefringence

Abstract The main problem with optical planar waveguide is thermal stress which arises when layers inside the planar waveguide get fused together with different coefficient of thermal expansion (CTE) and due to variation in thermal properties, the problem of thermally induced strain and birefringence occurs inside the waveguide glass layer. In proposed work, the mathematical analysis of thermal induced stress and the thermal strain in waveguide glass layer is calculated. ‘C’ software is used for analysis of an optical planar waveguide to calculate the thermal stress. By using material properties of Invar (64 % iron-36 % nickel alloy) and silicon nitride (Si 3 N 4 ) an optical planar waveguide is designed. Here when silicon nitride (Si 3 N 4 ) is used as a cladding layer and Invar (64 % iron-36 % nickel alloy) as a core layer in an optical planar waveguide, the problem of birefringence get eradicated as zero thermal stress was achieved.