Temperature profile in asymmetric heating by arc Discharge for wavelength insensitive fused fiber couplers

The temperature profile formed by arc discharge around the coupler waist of 2×2 couplers by placing the coupler waist away from the arc flame produces phase mismatch between the fibers. Theoretically, the propagation constants are found out considering effective core diameters, core dopant diffusion, and coupling coefficient around coupler waist. The refractive index variation with the change of glass structure depending on the temperature profile parameters is utilized to fabricate wavelength insensitive devices. A theoretical model for splitting ratio versus wavelength with repeated discharges for increasing the phase mismatch considering temperature profile parameters is developed. The theoretical curves are compared with the experimental results.