FIELD: manufacture of large-diameter optical fiber. SUBSTANCE: method involves fixing and aligning blank rod in upper cartridge; securing and aligning glass tube in lower chuck; axially introducing blank rod into glass tube; preliminarily heating glass tube in furnace with following heating by means of burner until temperature of glass tube reaches softening temperature value; sealing blank rod in glass tube through creating vacuum by sucking air from gap between blank rod and glass tube wall to produce blank. Apparatus has burner and furnace, which are mounted on carriage for heating or preliminarily heating of glass tube and squeezing it along blank rod. EFFECT: increased efficiency by uniform temperature distribution over peripheral surface of glass tube. 16 cl, 7 dwg
