OPTICAL FIBER DEVICE

PURPOSE:To decrease the number of parts and to improve reliability by applying a creamy welding material onto the exothermic part atop a heat insulator fixed onto a substrate, then imposing an optical fiber adjusted in optical axis thereon and energizing the exothermic part so that the exothermic part is fixed by the welding material. CONSTITUTION:The heat insulator 11 having the exothermic part 12 is fixed onto the substrate 1 and after the creamy welding material 8 is applied on this exothermic part 12, the optical fiber 7 adjusted in the optical axis with respect to a photosemiconductor element 3 fixed onto the substrate is imposed on the substrate and the exothermic part 12 is energized to melt the welding material 8, by which the optical fiber 7 is fixed. The number of parts in the optical fiber part and the adhesive parts between these parts are then decreased and, therefore, the misalignment of the optical axis by a secular change, etc., are decreased. The long-term reliability is thus improved and the cost is reduced.