Study On Drawing Process And Properties Of Large Diameter And Ultra Long Optical Fiber Preform

Because of the development of optical fiber communication,the demand for optical fiber increasing.The optical fiber manufacturers' manufacturing scale and production capacity continues to expand,So that the optical fiber preform become larger and longer.With the increase of the preform size,the related optical fiber drawing process problems need to be solved.In this paper,the optical fiber drawing process and the properties of the large diameter and ultra long preform were studied.The influence of the diameter and length of the preform on the optical fiber drawing furnace and coating system were studied.The intra-stress of the optical fiber after the increase of the preform diameter was analyzed.The main research results are as follows:(1)Using FLUENT to analyze the gas distribution and flow rate in the optical fiber drawing furnace,the temperature field distribution in the optical fiber drawing furnace was simulated.By improving the structure of the optical fiber drawing furnace,the temperature field distribution was optimized.The influence factors of optical fiber drawing furnace on the fiber non-circularity and strength were analyzed.Through the improvement of the optical fiber drawing furnace and the optimization of the drawing process,the average value of the fiber non-circularity is less than 0.3%.(2)The effect of optical fiber drawing with large diameter and ultra long preform on coating quality was studied.By improving the coating feeding system,the problem of coating bubble was solved.Through the improvement of coating material and UV curing system,the problem of the decrease of curing degree caused by long time drawing of the large diameter and ultra long preform was solved.(3)The increasing intra-stress of the optical fiber caused by the increase of the preform diameter is studied and solved.A method to reduce the intra-stress of optical fiber by using annealing furnace is presented.The principle of the annealing technology was analyzed from theoretical level,and the variation of the attenuation,curl and brittle of the optical fiber with or without the annealing furnace was investigated from the contrast test,respectively.he result showed that the typical value of the attenuation on 1310 nm is 0.317dB/km and the 1550 nm is 0.182dB/km,the value of the curl is more than 14 m and the broken rate of peeling off is low to 0.08%.(4)Through the test of the optical fiber performance index and the type test,all the indexes were in line with or better than the national standard.It was proved that the drawing process is stable and has the popularization and practicality.