An annealing furnace design has been proposed to lower the attenuation of optical fiber by lowering its fictive temperature during the fiber draw process.The fictive temperature of Germania-doped single mode o fiber lies in the range of 1150~1300 C and this can be tailored by controlling the cooling rate of fiber during its draw process. The annealing furnace has been designed using Computational Fluid Dynamics (CFD) simulation tool and has resulted in lowering the attenuation due to Rayleigh scattering loss at 1550 nm by 0.003 dB/km.
A method has been proposed to reduce the attenuation due to Rayleigh scattering loss in the single mode optical fiber (mainly attributed to the density and concentration fluctuations at atomic/molecular level) by lowering the fictive temperature during the fiber draw process. The fictive temperature of a Germaniao doped single mode optical fiber varies between 1150-1300 C and no further structural relaxation occurs in glasses above this temperature. The article presents a computational study on the design of annealing furnace aimed at controlling the cooling rate of optical fiber during its draw process, thus resulting in lowered fictive temperature.
