Fiber Optic Preform Manufacturing Process

VAD Core Deposition

SiCl4 Steam and GeCl4 Steam generated by the vapor system is oxidized reaction and hydrolyzed reaction with H2/O2 at the outlet of the burner to form fine SiO2 and GeO2 particles. The particles are axial deposition by the thermophoresis effect to prepare the soot preform.

Core Dehydration and Sintering

In 1000-1200℃ temperature conditions, the process gases such as He and Cl2 are pumped into the furnace, making the soot preform pass through the heating furnace hot area slowly thus removing the OH group and meral impurities. In 1400-1600℃ temperature conditions, pumping the He and other gases into the furnace, making the soot preform pass through the heating furnace hot area slowly which will sinter the soot preform change to transparent core.

Core Measurement

Imported equipment can automatically analyze the optical properties of optical fiber preforms. The geometric parameters of the preform, refractive index, diameter, and concentricity can be calculated. The profile parameters also produce equivalent step-index distribution data to predict the performance of the drawn fiber and provide the necessary feedback to the preform production process.

Core Elongation

After the prepared large-size mandrel is aligned with the tail shank, it is softened by heating at 2000-2200 ° C in a high-temperature furnace. The large-size preform is extended to a smaller size by the difference in speed between the upper and lower tail shanks.

OVD Clad Deposition

Oxidation and hydrolysis reactions of SiCl4 vapor and CH4/O2 produced by the evaporation system at the torch produce SiO2, 4HCL, CO2 to form powdered SIO2 particles. The particles were laterally deposited under the thermophoresis effect to prepare a preform loose body.

Clad Dehydration and Sintering

The upper furnace temperature is set at 1000-1200 ° C, and the lower furnace temperature is set at 1400-1600 ° C. A process gas such as He and Cl2 is introduced into the furnace so that the loose body passes through the upper and lower end heating furnaces in sequence so that dehydration and sintering are simultaneously performed.

Clad Soaking

The high-temperature negative pressure treatment method can quickly remove the residual He gas in the optical fiber preform, effectively remove the air bubbles in the optical fiber preform, and improve the processing quality of the optical fiber preform.


After the production of the preform is completed, it is necessary to check whether there is a defect by glare, and measure the direct and effective weight of the preform and then package it into the warehouse.

Product Director: James Xu


Linkedin:  James xu

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