Profile development during the isothermal drawing of the hollow all-polymer Bragg fibers is studied in the case when surface tension is strong enough to cause a hole collapse. The viscoelastic model of polymer flow is considered, and a comparison with the simpler Newtonian and generalized Newtonian models is made. The effects of draw ratio, draw temperature, feeding speed, core pressurization, and mismatch of material properties in the multilayer structure are investigated. A relation between the hole collapse and the layers nonuniformity is presented, and their effect on the fiber-transmission properties is investigated.
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