Abstract:
According to some embodiments a method of processing an optical fiber comprises the steps of: (i) drawing the fiber at a drawing rate of at least 30 m/sec; and (ii) cooling the drawn fiber in a gas at an average cooling rate less than 5000 °C/s, such that said cooling reduces the temperature of the fiber from an entering temperature in the range between 1500 °C and 1700 °C to another temperature in the range between 1200 °C and 1400 °C, the gas being at a temperature between 800 °C and 1500 °C; and the thermal conductivity K of the gas being not greater than 1.5xl0" 4 cal/cm-s-K for at least one temperature within a range of 800 °C to 1500 °C at one atm (atmosphere) pressure absolute.
Abstract:
A section of active optical fiber (11) which comprises an active core (1), an inner cladding layer (2) and an outer cladding layer (3). The diameter of said core (1) and the thickness of said inner cladding (2) change gradually along the length of said section of active optical fiber (11). This forms a tapered longitudinal profile enabling a continuous mode conversion process along the length of the section of fiber (11). The method for fabricating a section of tapered active optical fiber comprises the steps of fabricating a preform for drawing active optical fiber from said preform, installing said preform into a drawing tower, drawing optical fiber in said drawing tower and altering at least one of the two parameters including the take-off preform speed and the take-up fiber speed during drawing of the optical fiber.
Abstract:
A process and system for controllable production of continuous lengths of microwire having a core covered by a glass coating are provided. According to the method of the invention, a glass tubing is loaded with a core material. Thereafter, the process includes the step of heating the tubing containing the core material for melting thereof, softening a tip of the glass tubing and forming a drop of the core material in the molten state surrounded by an outer glass shell. During the process, the gas is evacuated from the glass tubing in order to control elevation of the drop. The method includes drawing the heated outer glass shell into a continuous microwire filament and stabilizing the temperature and mass of the drop during the process. Accordingly, the system includes a suitable glass feeder mechanism, a rod feeder mechanism, a furnace configured for forming a drop of the core material in the molten state surrounded by an outer glass shell, controllable vacuum and cooling devices and a receiver section for receiving the microwire obtained after the cooling. The system also includes a controller and sensing means configured for producing signals representative of the gas pressure in the tubing, temperature temperature of the drop, the speed of the microwire, the value of the microwire diameter, the value of the spool diameter and other relevant parameters.
Abstract:
A section ofactive optical fiber (11) which comprises an active core (1),an inner cladding layer (2) andan outer cladding layer (3).The diameter of said core (1) and the thickness of said inner cladding (2) change gradually along the length of said section of active optical fiber (11). This formsa tapered longitudinal profile enabling a continuous mode conversion process alongthe length of the section of fiber (11). The method for fabricating a section of tapered active optical fibercomprises the steps of fabricating a preform for drawing active optical fiber from said preform,installing said preform into a drawing tower, drawing optical fiber in said drawing tower and altering at least one of the two parameters including the take-off preform speed and the take-up fiber speed during drawing of the optical fiber.
Abstract:
A process and system for controllable production of continuous lengths of microwire having a core covered by a glass coating are provided. According to the method of the invention, a glass tubing is loaded with a core material. Thereafter, the process includes the step of heating the tubing containing the core material for melting thereof, softening a tip of the glass tubing and forming a drop of the core material in the molten state surrounded by an outer glass shell. During the process, the gas is evacuated from the glass tubing in order to control elevation of the drop. The method includes drawing the heated outer glass shell into a continuous microwire filament and stabilizing the temperature and mass of the drop during the process. Accordingly, the system includes a suitable glass feeder mechanism, a rod feeder mechanism, a furnace configured for forming a drop of the core material in the molten state surrounded by an outer glass shell, controllable vacuum and cooling devices and a receiver section for receiving the microwire obtained after the cooling. The system also includes a controller and sensing means configured for producing signals representative of the gas pressure in the tubing, temperature temperature of the drop, the speed of the microwire, the value of the microwire diameter, the value of the spool diameter and other relevant parameters.
Abstract:
A method an apparatus for continuously producing optical waveguide fiber and preforms. A continuous supply of core cane is provided to a walled deposition chamber upon which glass soot is deposited to form a soot preform. The preform is passed through an aligned drying, consolidation and draw chambers from which an optical fiber may be drawn. In one embodiment, a plurality of burners are positioned at different radial distances from a longitudinal axis of the cane in the deposition chamber. One or more environmental seal(s) are provided to prevent process gasses or contaminants from flowing into or between the chambers.
Abstract:
Method of making a microstructured optical fiber. Silica glass based soot is deposited on a substrate to form at least a portion of an optical fiber preform by traversing a soot deposition burner with respect to said substrate at a burner traverse rate greater than 3 cm/sec, thereby depositing a layer of soot having a thickness less than 20 microns for each of a plurality of burner passes. At least a portion of the soot preform is then consolidated inside a furnace to remove greater than 50 percent of the air trapped in said soot preform, said consolidating taking place in a gaseous atmosphere containing krypton, nitrogen, or mixtures thereof under conditions which are effective to trap a portion of said gaseous atmosphere in said preform during said consolidation step, thereby forming a consolidated preform which when viewed in cross section will exhibit at least 50 voids therein.
Abstract:
Disclosed is a heating element having a ring shape provided in a furnace for drawing an optical fiber from a large-diameter preform so as to heat and melt a preform. The heating element according to heating element includes at least two hot zones having different heating temperatures, wherein one of the hot zones is arranged in a neck-down region of the preform to heat the preform at a temperature suitable for drawing an optical fiber. Also, the hot zone includes a first heating unit for heating a preform at a temperature suitable for draw an optical fiber from the preform; and a second heating unit for heating a surface of the preform to a relatively lower temperature than the first heating unit.