Method and apparatus for producing optical fiber coupler

In a method of producing an optical fiber coupler, in which a plurality of optical fibers are arranged in parallel with each other, glass portions of the optical fibers are heated so as to be fusion bonded to each other integrally and then, the integral glass portions are heated so as to be stretched, the method comprising:

• providing a gas burner which acts as a heating device and has a slitlike gas nozzle longitudinally extending in parallel with an axial direction of the optical fibers so as to be fixed in position during heating of the glass portions;
• wherein the gas nozzle disposed at a central portion of the gas burner is spaced farther away from the glass portions then the gas nozzle disposed at opposite end portions of the gas burner.

In a method of producing an optical fiber coupler, in which a plurality of optical fibers are arranged in parallel with each other, glass portions of the optical fibers are heated so as to be fusion bonded to each other integrally and then, the integral glass portions are heated so as to be stretched, the method comprising:

• providing a gas burner which acts as a heating device and has a pair of first slitlike gas nozzles and a second slitlike gas nozzle arranged in parallel with an axial direction of the optical fibers so as to be fixed in position during heating of the glass portions;
• the first slitlike gas nozzles being, respectively, disposed at opposite end portions of the gas burner, while the second slitlike gas nozzle is disposed at a central portion of the gas burner such that the second slitlike gas nozzle is spaced farther away from the glass portions than the first slitlike gas nozzles are.

An apparatus for producing an optical fiber coupler, in which a plurality of optical fibers are arranged in parallel with each other, glass portions of the optical fibers being heated so as to be fusion bonded to each other integrally and then, the integral glass portions being heated so as to be stretched, the apparatus comprising:

• a gas burner which acts as a heating device and has a plurality of gas nozzles arranged in parallel with an axial direction of the optical fibers, said gas burner being fixed in position during heating of the glass portions;
• the gas nozzles including first gas nozzles disposed at opposite end portions of the gas burner and second gas nozzles disposed at a central portion of the gas burner such that the second gas nozzles are spaced farther away from the glass portions than the first gas nozzles are when the glass portions are being heated.

In an apparatus for producing an optical fiber coupler, in which a plurality of optical fibers are arranged in parallel with each other, glass portions of the optical fibers being heated so as to be fusion bonded to each other integrally and then, the integral glass portions being heated so as to be stretched, the apparatus comprising:

• a gas burner which acts as a heating device and has a slitlike gas nozzle longitudinally extending in parallel with an axial direction of the optical fibers, said gas burner being fixed in position during heating of the glass portions;
• wherein the gas nozzle disposed at a central portion of the gas burner is spaced farther away from the glass portions than the gas nozzle disposed at opposite end portions of the gas burner, when the glass portions are being heated.

In an apparatus for producing an optical fiber coupler, in which a plurality of optical fibers are arranged in parallel with each other, glass portions of the optical fibers being heated so as to be fusion bonded to each other integrally and then, the integral glass portions being heated so as to be stretched, the apparatus comprising:

• a gas burner which acts as a heating device and has a pair of first slitlike gas nozzles and a second slitlike gas nozzle arranged in parallel with an axial direction of the optical fibers, said gas burner being fixed in position during heating of the glass portions;
• the first slitlike gas nozzles being, respectively, disposed at opposite end portions of the gas burner, while the second slitlike gas nozzle is spaced farther away from the glass portions than the first slitlike gas nozzles are when the glass portions are being heated.