# US 2009/0260401 A1 · Heater having multi hot-zones, furnace having the heater for drawing down optical fiber preform into optical fiber, and method for drawing optical fiber using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0260401 A1 - Document ID: US20090260401A1 - Status: Published application - Kind: A1 - Application number: 12/279,636 - Filed: 2006-11-13 - Published: 2009-10-22 - Earliest claimed: 2006-02-15 - Inventors: Hyung-Soo Shin; Young-Gyu Yang; Lae-Hyuk Park - Web page: https://patentgrep.com/patent/US20090260401A1 ## CPC - C03B 37/029: Furnaces therefor - C03B 2205/40: Monitoring or regulating the draw tension or draw rate - C03B 2205/44: Monotoring or regulating the preform feed rate - C03B 2205/63: Ohmic resistance heaters, e.g. carbon or graphite resistance heaters - Y02P 40/57: Improving the yield, e-g- reduction of reject rates - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## 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. ## Claims ### Claim 1 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, wherein the heating element comprises at least two hot zones having different heating temperatures, and wherein one of the hot zones is arranged in a neck-down region of the preform so as to heat the preform at a temperature suitable for drawing an optical fiber. ### Claim 2 (depends on 1) The heating element according to claim 1, wherein the hot zone includes: a first heating unit for heating the preform at a temperature suitable for drawing 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, wherein the first heating unit is arranged in a neck-down region of the preform, and the second heating unit is arranged above the neck-down region. ### Claim 3 (depends on 2) The heating element according to claim 2, wherein the heating element is an electric resistance heater made of graphite or carbon material. ### Claim 4 (depends on 3) The heating element according to claim 3, wherein the first heating unit has a relatively smaller thickness than the second heating unit. ### Claim 5 (depends on 3) The heating element according to claim 3, wherein the first heating unit has an heating temperature of 1,800 to 2,300° C., and the second heating unit has an heating temperature of 1,500 to 1,800° C. ### Claim 6 A furnace for drawing an optical fiber, the furnace comprising: a furnace body having an top opening through which an optical fiber preform is introduced and a bottom opening through which an optical fiber drawn from the preform is discharged; a gas supply means for flowing an inert gas into a furnace body to maintain the inside of the furnace body under an inert gas atmosphere; and a heating means installed inside the furnace body and heating the optical fiber preform to draw an optical fiber, wherein the heating means includes: a first heating unit for heating a preform at a temperature suitable for drawing 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, wherein the first heating unit is arranged in a neck-down region of the preform, and the second heating unit is arranged above the neck-down region. ### Claim 7 (depends on 6) The furnace for drawing an optical fiber according to claim 6, wherein the heating means is an electric resistance heater made of graphite or carbon material. ### Claim 8 (depends on 7) The furnace for drawing an optical fiber according to claim 7, wherein the first heating unit has a relatively smaller thickness than the second heating unit. ### Claim 9 (depends on 8) The furnace for drawing an optical fiber according to claim 8, wherein the first heating unit has an heating temperature of 1,800 to 2,300° C., and the second heating unit has an heating temperature of 1,500 to 1,800° C. ### Claim 10 A method for drawing an optical fiber by melting a preform in a furnace that includes an electric resistance heater made of graphite or carbon material, the electric resistance heater including: a first heating unit for heating a preform at a temperature suitable for drawing 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, wherein the method comprises: (a) supplying a preform into the inside of the furnace; (b) arranging the preform and the heater so that a neck-down region of the preform corresponds to the first heating unit and an upper part of the neck-down region of the preform corresponds to the second heating unit; (c) applying power to the heater such that the first heating unit and the second heating unit generate heat at different temperatures; (d) drawing an optical fiber by heating a surface of the preform arranged in the neck-down region to a first temperature; and (e) heating a surface of the preform arranged above the neck-down region to a second temperature lower than the first temperature. ### Claim 11 (depends on 10) The method for drawing an optical fiber according to claim 10, wherein the first temperature ranges from 1,800° C. to 2,300° C., and the second temperature ranges from 1,500° C. to 1,800° C.