EP0245716A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for forming doped optical preforms
Assignee: Polaroid Corp
•
Filing: 1987-04-30
•
Granted: —
•
Expires: 2007-04-30
Abstract
Abstract An optical fiber preform is formed by plasma chemical vapor deposition utilizing a plasma torch (10) that includes a chamber into which a plasma starting gas, such as argon, is introduced (30) and converted to a plasma by application of high frequency electromagnetic energy. A suitable entry port (34) is provided in the torch chamber to allow dopant material (36) in solid form to be introduced directly into the plasma for vaporization or ionization. The dopant material (36) passes into a lower temperature region where gaseous silica precursor gases are introduced (38,40) to undergo reaction in the presence of the vaporized dopant to form appropriately doped silica particles (16) for deposition onto a substrate (18). Solid dopants (36) of low volatility or vapor pressure may be used as dopants which could not otherwise be used in vapor deposition processes. The absence of hydrogen in the reaction dynamics results in a preform having greatly reduced hydroxyl ion content. If desired, a high-purity starting glass, rather than the precursor gases, can be introduced directly into the plasma to form the appropriately doped material.
Inventors
- 👤 Robert J. Mansfield
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 02:49
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/50; C23C16/513; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/0128; C03B37/01291; C03B37/014; C03B37/01413; C03B37/0142; C03B37/01426; C03B2201/00; C03B2201/06; C03B2201/30; C03B2201/34
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
56 words
A method for forming an optical fiber preform comprising the steps of: forming a plasma; introducing a solid dopant into the plasma to effect vaporization thereof; introducing silica precursor gases into the vaporized dopant in a temperature range for effecting reaction thereof to form doped silica particles; and accumulating the doped silica particles on a substrate.
Claim 2
Independent Claim
56 words
A method for forming an optical fiber preform comprising the steps of: forming a plasma; introducing a solid dopant into the plasma to effect vaporization thereof; introducing silica precursor gases into the vaporized dopant in a temperature range for effecting reaction thereof to form doped silica particles; and accumulating the doped silica particles on a substrate.
Claim 3
Dependent Claim
22 words
The method of claim 1, wherein said first-mentioned introducing step further comprises introducing the solid dopant into the plasma in particulate form.
Claim 4
Dependent Claim
21 words
The method of claim 1, wherein said second-mentioned introducing step further comprises introducing silicon tetrachloride and oxygen into the vaporized dopant.
Claim 5
Dependent Claim
30 words
The method of claim 1, wherein said first-mentioned introducing step further comprises controlling the rate of introduction of said dopant to control the percentage concentration thereof in the doped silica.
Claim 6
Dependent Claim
42 words
The method of claim 1, wherein said second-mentioned introducing step further comprises introducing silicon tetrachloride and oxygen into the vaporized dopant and controlling the rate of introduction thereof to control the percentage concentration of the introduced dopant in the doped silica particles.
Claim 7
Dependent Claim
17 words
The method of claim 1, wherein said plasma is formed by RF induction into a plasma-forming gas.
Claim 8
Dependent Claim
12 words
The method of claim 6, wherein said plasma forming gas is argon.
Claim 9
Independent Claim
67 words
A method for forming an optical fiber preform comprising the steps of: forming a plasma ; introducing a solid dopant material and a solid glasseous material into the plasma to effect vaporization thereof; passing the vaporized glasseous and solid dopant material to a temperature zone lower than that of the plasma to allow formation of doped glasseous particles; and accumulating the doped glasseous particles on a substrate.
Claim 10
Independent Claim
67 words
A method for forming an optical fiber preform comprising the steps of: forming a plasma ; introducing a solid dopant material and a solid glasseous material into the plasma to effect vaporization thereof; passing the vaporized glasseous and solid dopant material to a temperature zone lower than that of the plasma to allow formation of doped glasseous particles; and accumulating the doped glasseous particles on a substrate.
Claim 11
Dependent Claim
38 words
9 . The method of claim 8, wherein said introducing step further comprises controlling the rate of introduction of the dopant and the glasseous material to control the percentage concentration of the dopant in the doped glasseous particles.
Claim 12
Dependent Claim
17 words
The method of claim 8, wherein said plasma is formed by RF induction into a plasma-forming gas.
Claim 13
Dependent Claim
12 words
ll. The method of claim 10, wherein said plasma-forming gas is argon.
Claim 14
Independent Claim
57 words
An apparatus for forming doped silica comprising: means for forming a plasma; means for containing the plasma; means for introducing a solid dopant material into the plasma to effect vaporization thereof; and means for introducing gaseous silica precursor reactants into said vaporized dopant material in a temperature range for effecting reaction thereof to form doped silica particles.
Claim 15
Independent Claim
57 words
An apparatus for forming doped silica comprising: means for forming a plasma; means for containing the plasma; means for introducing a solid dopant material into the plasma to effect vaporization thereof; and means for introducing gaseous silica precursor reactants into said vaporized dopant material in a temperature range for effecting reaction thereof to form doped silica particles.
Claim 16
Dependent Claim
39 words
The apparatus of claim 14, wherein said means for containing the plasma comprises a burner tube having an open discharge end and entry ports for introducing said solid dopant, said gaseous silica precursor reactants, and a plasma forming gas.
Claim 17
Dependent Claim
30 words
The apparatus of claim 15, wherein said means for forming a plasma comprises an RF induction coil coupled to said burner tube and coupled to a source of RF energy.
Claim 18
Dependent Claim
32 words
The apparatus of claim 15, wherein said entry port for introducing said solid dopant is so located in said burner tube to allow introduction of a solid dopant directly into said plasma.
Claim 19
Independent Claim
47 words
An apparatus for forming doped silica comprising: means for forming a plasma; means for containing the plasma; and means for introducing a solid dopant material and a solid glasseous material into the plasma to effect a vaporization thereof, said vaporized materials combining to form doped glasseous particles.
Claim 20
Independent Claim
47 words
An apparatus for forming doped silica comprising: means for forming a plasma; means for containing the plasma; and means for introducing a solid dopant material and a solid glasseous material into the plasma to effect a vaporization thereof, said vaporized materials combining to form doped glasseous particles.
Claim 21
Dependent Claim
38 words
The apparatus of claim 18, wherein said means for containing the plasma comprises a burner tube having an open discharge end and entry ports for introducing said solid dopant material, a glasseous material, and a plasma forming gas.
References Cited (Backward Citations)
GB1520587A
Cited
EP0086132A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.