초록 ▼

A method of making a glass optical fiber having a core surrounded by cladding containing diametrically opposed regions of different TCE than the cladding. Three manufacturing techniques are disclosed. (1) A first glass rod having core and cladding glass is placed centrally in a glass tube. Rods of g

A method of making a glass optical fiber having a core surrounded by cladding containing diametrically opposed regions of different TCE than the cladding. Three manufacturing techniques are disclosed. (1) A first glass rod having core and cladding glass is placed centrally in a glass tube. Rods of glass having a TCE different from that of the cladding glass are put on opposite sides of the first rod. Rods of cladding glass are placed in the interstices. (2) A soot preform is deposited on a rotating mandrel. In one embodiment, mandrel rotation is halted to deposit one longitudinally extending region and then rotated 180°to deposit the other such region. In a modified embodiment the mandrel continuously rotates and the deposition burner is continuously supplied with reactant gas for forming a base glass and is also provided with pulses of a reactant gas for modifying the base glass to form the diametrically opposed regions. (3) A CVD process is modified by inserting a pair of tubes into the substrate tube when the longitudinally extending regions are to be deposited. There is passed between the first tube and the pair of tubes a gas which reacts to form particles of a base glass and there is passed through the pair of tubes another gas which reacts to form dopant glass particles which combine with base glass particles to form longitudinal strips of doped base glass within the tube.

대표청구항 ▼

The method of forming an optical waveguide comprising the steps of providing a substantially cylindrical mandrel, providing burner means for emitting a stream of glass soot, rotating said mandrel, reciprocatingly moving said burner means longitudinally along said rotating mandrel to deposit on said

The method of forming an optical waveguide comprising the steps of providing a substantially cylindrical mandrel, providing burner means for emitting a stream of glass soot, rotating said mandrel, reciprocatingly moving said burner means longitudinally along said rotating mandrel to deposit on said mandrel a first coating of glass soot, reciprocatingly moving said burner means longitudinally along said rotating mandrel to deposit on the outer surface of said first coating a second coating of glass soot having a refractive index lower than that of said first coating, halting rotation of said mandrel, moving said burner means longitudinally with respect to said mandrel while depositing on said second coating a first crescent-shaped longitudinally extending region of glass soot having a thermal coefficient of expansion different from that of said second coating, rotating said mandrel 180°and thereafter again halting mandrel rotation, moving said burner means longitudinally with respect to said mandrel while depositing a second crescent-shaped longitudinally extending region of glass soot that is of the same composition as said first region, said second region being azimuthally spaced from and diametrically opposed to said first region, depositing on the outer surface of the resultant soot body a coating of cladding soot having a thermal coefficient of expansion similar to that of said second coating and having a refractive index equal to or lower than that of said second coating, removing said mandrel, and forming an optical waveguide fiber from the resultant soot preform. A method of forming an optical waveguide preform comprising the steps of providing a tube of cladding glass, disposing centrally within said tube a first glass rod having an axially disposed core region surrounded by a layer of cladding glass, disposing a first pair of glass rods diametrically with respect to the central rod within said tube, said first pair of rods being formed of a glass having a temperature coefficient of expansion different from that of said cladding glass, and disposing a plurality of rods of cladding glass in at least some of the interstices between said centrally disposed rod, said first pair of rods and said tube.