A contactless guide includes an inner member having a plurality of ejection ports capable of ejecting a gas in an outer peripheral surface, and a first flange and a second flange housing the inner member so as to sandwich the inner member in a first direction intersecting with an ejection direction of the gas ejected from the plurality of ejection ports. At least one of the first flange and the second flange is attached to the inner member such that a gap through which the gas ejected from the plurality of ejection ports passes is provided between an outer edge portion of the first flange and an outer edge portion of the second flange. At least one of the first flange and the second flange is movable in a direction in which a width of the gap is changed.

A method for producing an optical fiber. The method includes drawing an optical-fiber base material while heating and softening the optical-fiber base material to produce a part of the optical fiber to be a product, and determining whether a predetermined condition is satisfied to determine a drawing end of the optical fiber that is to be a product from the optical-fiber base material. In the drawing, a linear speed for drawing the optical fiber is controlled with a target value of the linear speed constant. In the determining, when the linear speed is decreased by a predetermined amount from the target value, the drawing end of the optical fiber is determined.

A manufacturing method of porous glass base material for optical fiber with suppressed characteristic fluctuation in the longitudinal direction is provided. A manufacturing method of optical fiber base material by the VAD method includes: detecting a tip position of a porous glass base material during deposition; controlling the pull-up speed to keep the tip position constant; in an early stage of deposition, a target pull-up speed is set for each deposition time, and a raw material gas flow rate to the burner is adjusted and corrected at a predetermined correction interval to achieve the target pull-up speed, thereby depositing while gradually changing the pull-up speed until a predetermined time; in a steady state, the deposition is performed such that the pull-up speed is kept constant to form the porous glass base material; and the porous glass base material is dehydrated and vitrified into transparent glass in a heating furnace.

An optical fiber drawing apparatus includes a drawing furnace configured to heat and soften an optical fiber base material and configured to draw the optical fiber, a capstan configured to pull and transport the optical fiber, a winding device configured to wind the optical fiber, a tensioning mechanism arranged between the capstan and the winding device and configured to test a strength of the optical fiber by tensioning the optical fiber, and a backup winding device arranged between the capstan and the tensioning mechanism and configured to temporarily wind the optical fiber when the optical fiber is broken.

Provided is a system for and a method of processing an optical fiber, such as tapering an optical fiber. The method includes receiving fiber parameters defining characteristics of an optical fiber, modeling an idealized fiber based on the fiber parameters to establish modeled data, and establishing processing parameters. A processing operation is performed on the optical fiber according to the processing parameters to produce a resultant fiber. Aspects of the resultant fiber are measured to establish measured data. The measured data and the modeled data are normalized to a common axis and a difference between the two is determined. The processing parameters are adjusted based on the differences.