U.S. patent application number 09/945961 was filed with the patent office on 2002-03-07 for co-flow diffusion flame burner device used for fabricating an optical waveguide.
Invention is credited to Cho, Jae-Geol.
Application Number | 20020028415 09/945961 |
Document ID | / |
Family ID | 19687509 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020028415 |
Kind Code |
A1 |
Cho, Jae-Geol |
March 7, 2002 |
Co-flow diffusion flame burner device used for fabricating an
optical waveguide
Abstract
The present invention provides a co-flow diffusion flame bunier
for use in fabricating an optical waveguide, which includes a
source material gas injection tube, through which a fuel gas, a
source material to be mixed with the fuel gas, and a dilution gas
to control the temperature of the flame generated by the combustion
of the fuel gas are injected; a shield gas injection tube, disposed
coaxially with the source material gas injection tube at the
exterior of the source material gas injection tube and through
which a shield gas is injected to prevent the particles produced by
the combustion reaction of the fuel gas and an oxidation gas from
sticking to the end of the source material gas injection tube; and,
an oxidation gas injection tube, disposed coaxially with the shield
gas injection tube at the exterior of the shield gas injection tube
and through which an oxidation gas is injected to react with the
fuel gas.
Inventors: |
Cho, Jae-Geol; (Seoul,
KR) |
Correspondence
Address: |
KLAUBER & JACKSON
411 HACKENSACK AVENUE
HACKENSACK
NJ
07601
|
Family ID: |
19687509 |
Appl. No.: |
09/945961 |
Filed: |
September 4, 2001 |
Current U.S.
Class: |
431/187 |
Current CPC
Class: |
C03B 2207/06 20130101;
C03B 2207/26 20130101; C03B 2207/22 20130101; C03B 2207/66
20130101; C03B 2207/24 20130101; C03B 19/1423 20130101; F23D 14/22
20130101; C03B 19/1415 20130101; C03B 2207/20 20130101 |
Class at
Publication: |
431/187 |
International
Class: |
F23C 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2000 |
KR |
2000-52473 |
Claims
What is claimed is:
1. A co-flow diffusion flame burner device for use in fabricating
an optical waveguide comprising: a source material gas injection
tube, through which a fuel gas, a source material to be mixed with
the fuel gas, and a dilution gas to control the temperature of a
flame generated by the combustion of the fuel gas are injected; a
shield gas injection tube, disposed coaxially with the source
material gas injection tube at the exterior of the source material
gas injection tube and through which a shield gas is injected to
prevent the particles produced by the combustion reaction of the
fuel gas and an oxidation gas from sticking to the end of the
source material gas injection tube; and, an oxidation gas injection
tube, disposed coaxially with the shield gas injection tube at the
exterior of the shield gas injection tube and through which an
oxidation gas is injected to react with the fuel gas.
2. The device according to claim 1, wherein the dilution gas
comprises an inert gas.
3. The device according to claim 1, wherein the shield gas
comprises an inert gas.
4. The device according to claim 1, wherein the source material is
selected from the group consisting of SiCl.sub.4, GeCl.sub.4,
POCl.sub.3, and BCl.sub.3.
5. The device according to claim 1, wherein the dilution gas is
selected from the group consisting of He, Ar, and N.sub.2.
6. A co-flow diffusion flame burner device for use in fabricating
an optical waveguide comprising: a first source material gas
injection tube through which a fuel gas, a source material to be
mixed with the fuel gas, and a dilution gas to control the
temperature of a flame generated by the combustion of the fuel gas
are injected; a first shield gas injection tube, disposed coaxially
with the first source material gas injection tube at the exterior
of the first source material gas injection tube and through which a
shield gas is injected to prevent the particles produced by the
combustion of the fuel gas from sticking to the end of the first
source material gas injection tube; a first oxidation gas injection
tube, disposed coaxially with the first shield gas injection tube
at the exterior of the first shield gas injection tube and through
which an oxidation gas is injected to react with the fuel gas; a
second shield gas injection tube, disposed coaxially with the first
oxidation gas injection tube at the exterior of the first oxidation
gas injection tube and through which a shield gas is injected to
prevent the particles produced by the combustion reaction of the
oxidation gas and the fuel gas from sticking to the end of the
second shield gas injection tube; a second source material gas
injection tube, disposed coaxially with the second shield gas
injection tube at the exterior of the second shield gas injection
tube and through which a fuel gas, a source material to be mixed
with the fuel gas and a dilution gas to control the temperature of
a flame generated by the combustion of the fuel gas are injected; a
third shield gas injection tube, disposed coaxially with the second
source material gas injection tube at the exterior of the second
source material gas injection tube and through which a shield gas
is injected to prevent particles produced by the combustion
reaction of the fuel gas and the oxidation gas from sticking to the
end of the second source material gas injection tube; and, a second
oxidation gas injection tube, disposed coaxially with the third
shield gas injection tube at the exterior of the third shield gas
injection tube and through which an oxidation gas is injected to
react with the fuel gas.
7. The device according to claim 6, wherein the dilution gas
comprises an inert gas.
8. The device according to claim 6, wherein the shield gas
comprises an inert gas.
9. The device according to claim 6, wherein the source material is
selected from the group consisting Of SiCl.sub.4, GeCl.sub.4,
POCl.sub.3, and BCl.sub.3.
10. The device according to claim 6, wherein the dilution gas is
selected from the group consisting of He, Ar, and N.sub.2.
11. A process for fabricating an optical waveguide using a co-flow
diffusion flame burner, the method comprising the steps of:
introducing a fuel gas with a source material or a dilution gas
into one end of the diffusion flame burner; introducing an
oxidation gas into the one end of the diffusion flame burner;
generating a flame at the one end of the diffusion flame burner
where the fuel gas and the oxidation gas impinge; and,
simultaneously introducing an inert gas to the one end of the
diffusion flame burner to prevent the particles produced by the
combustion of the fuel gas from sticking to the one end of the
diffusion flame burner.
12. The process according to claim 11, further comprising the step
of bubbling the source material with the fuel gas or the dilution
gas.
13. The process according to claim 11, wherein the source material
is selected from the group consisting of SiCl.sub.4, GeCl.sub.4,
POCl.sub.3, and BCl.sub.3.
14. The process according to claim 11, wherein the dilution gas is
selected from the group consisting of He, Ar, and N.sub.2.
Description
CLAIM OF PRIORITY
[0001] This application makes reference to and claims all benefits
accruing under 35 U.S.C. Section 119 from an application entitled
"CO-FLOW DIFFUSION FLAME BURNER DEVICE FOR FABRICATING OF AN
OPTICAL WAVEGUIDE," filed in the Korean Industrial Property Office
on Sep. 5, 2000, and there duly assigned Ser. No. 00-52473.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a device for fabricating an
optical waveguide, and, more particularly, to a co-flow diffusion
flame burner device that is used in fabricating an optical
waveguide.
[0004] 2. Description of the Related Art
[0005] Generally, an optical waveguide, which is widely used as an
optical signal transmission medium in optical communication
systems, is fabricated by depositing source material, such as
SiO.sub.2, GeO.sub.2, P.sub.2O.sub.5 or B.sub.2O.sub.3, on a
silicone substrate, tube, etc. There are axial deposition method,
flame hydrolysis deposition, etc.
[0006] In particular, the flame hydrolysis deposition method is
specifically used in fabricating an optical waveguide. It involves
depositing glass material on the silicon substrate by a means of
oxy/hydrogen flame that is generated from a co-flow diffusion flame
burner.
[0007] FIG. 1 is a schematic view illustrating the procedures for
forming an optical waveguide thin layer on a substrate using the
conventional flame hydrolysis deposition method. As shown in FIG.
1, the source material undergoes hydrolysis and oxidation while
passing through the oxy/hydrogen flame that is generated by the
co-flow diffusion flame burner device 1 to form fine particles
known as "glass soot".
[0008] The "glass shoots" are coagulated when the particles collide
as they travel through the flame, then deposited on the silicon
substrate 10 by thermophoresis. At this point, by controlling the
composition ratio of the source material, the thin layers,
including an undercladding layer 20, a core layer 30 and an
overcladding layer (not shown), are formed one after another, as
shown in FIG. 1.
[0009] The deposition steps maybe carried out by disposing several
sheets of silicon substrate 10 on a rotating turntable while
traversing the co-flow diffusion flame burner device 1 (indicated
by M.sub.1), or by reciprocally moving the co-flow diffusion flame
burner device 1 along the two-dimensional line (indicated by
M.sub.2) while the silicon substrate 10 is stationary.
[0010] FIG. 2 is a perspective view of the co-flow diffusion flame
burner according to the prior art system. As shown in FIG. 2, the
co-flow diffusion flame burner 100 according to the prior art
consists of an injection tube for source material/carrier gas 110
with a plurality of tubes arranged co-axially, an injection tube
for fuel/dilution gas 120, and an injection tube for oxidation gas
130.
[0011] The injection tube for source material/carrier gas 110 is
used for injecting the source material S and carrier gas gc, which
is used for bubbling the source material. The source materials used
are, for example, SiCl.sub.4, GeCl.sub.4, POCl.sub.3, and
BCl.sub.3. Most of these materials, except BCl.sub.3, are in a
liquid state at room temperature. Therefore, the source materials
must be bubbled through the carrier gas, gc. The carrier gas, gc,
are, for the formation of bubbles, He, Ar, and N.sub.2, for
example.
[0012] The injection tube for fuel/dilution gas 120 is used for
injecting the fuel gas to generate flame and the dilution gas,
g.sub.d, to control the temperature of the flame. As the fuel gas
H.sub.2 is used, the dilution gas, He, Ar, and the like--such as
those that can be diluted in hydrogen--are used.
[0013] The injection tube for oxidation gas 130 is used for
injecting the oxidation gas g.sub.o to generate the flame by a
combustion reaction with the fuel gas, g.sub.f. Here, O.sub.2 may
be used as the oxidation gas, g.sub.o.
[0014] Meanwhile, in the fabrication of the optical waveguide
according to the conventional flame hydrolysis deposition method,
it is very important that thin layers to be formed over the silicon
substrate have a uniform composition and thickness in order to
provide an optical waveguide with excellent optical transmission
properties. The formation of such thin layers can be accomplished
by realizing a uniform particle size distribution as well as a
uniform composition and number concentration distribution of the
glass soot that are produced from the co-flow diffusion flame
burner 100.
[0015] However, the conventional diffusion flame burner 100
exhibits a Gaussian type concentration distribution of source
material in which the concentration is high at the center of the
burner device and is gradually lowered away from the center.
Therefore, the composition of the glass soots forming the thin
layers on the silicon substrate varies with the distance from the
center and thus is difficult to form uniformly thin layers.
[0016] Furthermore, it is necessary that the source material travel
a certain distance from the injection nozzle end of the flame
burner before forming the glass soot. The traveling distance needed
to form the particles is increased when the flux of the source
material is higher. That is, in the conventional co-flow diffusion
flame burner 100, the concentration of the source material varies
radially from the center portion, thus leading to a variation in
the time required to form particles and the coagulation. Such
variation consequently leads to variations in the particle size of
the glass soot. Thus, the distribution of the size of the particles
is close to a log normal distribution. In addition, an increase in
the particle size and non-uniformity of the distribution of the
particle size may cause problems during the sintering process,
which is followed by the deposition process in fabricating an
optical waveguide.
SUMMARY OF THE INVENTION
[0017] The present invention is related to a co-flow diffusion
flame burner for use in fabricating an optical waveguide, by
producing glass soot with a reduced particle size and a uniform
distribution of the particle size.
[0018] Another aspect of the present invention is to provide a
co-flow diffusion flame burner for use in fabricating an optical
waveguide and that is capable of uniformly depositing the glass
soot over a predetermined broad area.
[0019] In another aspect, the present invention consists of a
co-flow diffusion flame burner for use in fabricating an optical
waveguide and includes a source material gas injection tube,
through which a fuel gas, a source material to be mixed with the
fuel gas, and a dilution gas to control the temperature of the
flame, which is generated by the combustion of the fuel gas, are
injected; an shield gas injection tube, disposed coaxially with the
source material gas injection tube at the exterior of the source
material gas injection tube and through which a shield gas is
injected to prevent the particles produced by the combustion
reaction of the fuel gas and an oxidation gas from sticking to the
end of the injection tube; and, an oxidation gas injection tube,
disposed coaxially with the shield gas injection tube at the
exterior of the shield gas injection tube and through which an
oxidation gas is injected to react with the fuel gas.
[0020] Another aspect of the present invention is directed to a
process for fabricating an optical waveguide using a co-flow
diffusion flame burner and includes the steps of: introducing a
fuel gas with a source material or a dilution gas into one end of
the diffusion flame burner; introducing an oxidation gas into the
one end of the diffusion flame burner; generating a flame at the
one end of the diffusion flame burner where the fuel gas and the
oxidation gas impinge; and, simultaneously introducing an inert gas
to the one end of the diffusion flame burner to prevent the
particles produced by the combustion of the fuel gas from sticking
to the one end of the diffusion flame burner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above advantages of the present invention will become
more apparent by describing in detail preferred embodiments thereof
with reference to the attached drawings in which:
[0022] FIG. 1 is a schematic view illustrating the procedure
according to a conventional art system for forming thin layers of
the optical waveguide on a substrate by the flame hydrolysis
deposition method;
[0023] FIG. 2 is a perspective view illustrating the conventional
co-flow diffusion flame burner;
[0024] FIG. 3 is a perspective view illustrating a co-flow
diffusion flame burner device according to a first preferred
embodiment of the present invention; and,
[0025] FIG. 4 is a perspective view illustrating a co-flow
diffusion flame burner device according to a second preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] In the following description, for purposes of explanation
rather than limitation, specific details are set forth such as the
particular architecture, interfaces, techniques, etc., in order to
provide a thorough understanding of the present invention. For
purposes of simplicity and clarity, detailed descriptions of
well-known devices, circuits, and methods are omitted so as not to
obscure the description of the present invention with unnecessary
detail.
[0027] FIG. 3 is a perspective view illustrating a co-flow
diffusion flame burner 200 according to the first preferred
embodiment of the present invention. As shown in FIG. 3, the
co-flow diffusion flame burner device 200 comprises a source
material gas injection tube 210, a shield gas injection tube 220,
and an oxidation gas injection tube 230.
[0028] Now, a detailed description will be made regarding this
invention with reference to the drawings.
[0029] 1. Source material gas injection tube 210
[0030] The source material gas injection tube 210 is used for
injecting a fuel gas g.sub.f, a source material S that is to be
mixed with the fuel gas g.sub.f, and a dilution gas g.sub.d to
control the temperature of the flame, which is generated by the
combustion of the fuel gas g.sub.f. The source materials for the
formation of glass soots are, for example, SiCl.sub.4, GeCl.sub.4,
POCl.sub.3, and BCl.sub.3. Also, as for the dilution gas, He, Ar,
N.sub.2, and other gas that may be diluted in hydrogen, are used.
The feeding rate of the fuel gas g.sub.f and the source material S
are selectively controlled by a mass flow controller (not
shown).
[0031] Prior to mixing the fuel gas g.sub.f and/or the dilution gas
g.sub.d, the source material S is supplied to a bubbler, to which
the fuel gas g.sub.f and/or the dilution gas g.sub.d is passed
through. Thus, in the present invention, the source material S is
not transferred by a specific carrier gas as in the prior art
system. Rather, the source material S is bubbled with the fuel gas
g.sub.f and/or the dilution gas g.sub.d and injected in a vapor
phase through the source material gas injection tube 210 of the
co-flow diffusion flame burner 200. As a result, the spot where the
source material is injected and the spot where the flame is
generated by the combustion of the fuel gas g.sub.f are same.
Hence, the glass soots are formed at the same time the combustion
of the fuel gas g.sub.f occurs.
[0032] Furthermore, since the hydrogen, which is used as the fuel
gas g.sub.f, has a diffusion coefficient greater than those of the
carrier gases which are used for transferring the source material
in the prior art, the glass soot can be formed over the broader
area in a short period of time. Therefore, the distribution of the
glass soot within the flame is uniform and the coagulation effect
of the particles is reduced, causing a reduction in the size of the
particles. Such uniform distribution and reduction in the particle
size enable the sintering process to be favorably carried out after
the deposition process.
[0033] 2. Shield gas injection tube 220
[0034] The shield gas injection tube 220 is disposed coaxially with
the source material gas injection tube 210 at the exterior of the
source material gas injection tube 210. This arrangement allows the
injection of a shield gas g.sub.s to prevent the particles produced
by the combustion of the fuel gas g.sub.f from sticking to the end
of the injection tube 210. As the shield gas g.sub.s, a small
amount of an inert gas may be used.
[0035] 3. Oxidation gas injection tube 230
[0036] The oxidation gas injection tube 230 is disposed coaxially
with the shield material gas injection tube 220 at the exterior of
the shield gas injection tube 220. This arrangement allows the
injection of an oxidation gas g.sub.o to react with the fuel gas
g.sub.f. Here, oxygen may be used as the oxidation gas g.sub.o.
[0037] FIG. 4 is a perspective view illustrating a co-flow
diffusion flame burner 300 according to the second preferred
embodiment of the present invention. As shown in FIG. 4, the
co-flow diffusion flame burner device 300 includes a first source
material gas injection tube 310; a first shield gas injection tube
320; a first oxidation gas injection tube 330; a second shield gas
injection tube 340; a second source material gas injection tube
350; a third shield gas injection tube 360; and, a second oxidation
gas injection tube 370.
[0038] The co-flow diffusion flame burner 300 according to the
second preferred embodiment of the present invention is capable of
forming uniformly thin layers over an area that is broader than the
above-described co-flow diffusion flame burner 200 according to the
first preferred embodiment of the present invention. This device
further comprises a source material gas injection tube, two shield
gas injection tubes, and an oxidation gas injection tube, in
addition to the source material gas injection tube, the shield gas
injection tube, and the oxidation gas injection tube.
[0039] With continued reference to FIG. 4, the first source
material gas injection tube 310 is used for injecting a fuel gas
g.sub.f, a source material S to be mixed with the fuel gas g.sub.f,
and a dilution gas g.sub.d to control the temperature of the flame,
which is generated by the combustion of the fuel gas g.sub.f. The
source materials may include SiCl.sub.4, GeCl.sub.4, POCl.sub.3,
BCl.sub.3, and the like may be used. For the dilution gas, He, Ar,
N.sub.2, and other gas that can be diluted in hydrogen may be
used.
[0040] The first shield gas injection tube 320 is disposed
coaxially with the first source material gas injection tube 310 at
the exterior of the first source material gas injection tube 310.
This arrangement allows the injection of a shield gas g.sub.s to
prevent the particles produced by the combustion of the fuel gas
g.sub.f, which is injected from the first source material gas
injection tube 310, from sticking to the end of the injection tube
310. For the shield gas g.sub.s, a small amount of an inert gas may
be used.
[0041] The first oxidation gas injection tube 330 is disposed
coaxially with the first shield gas injection tube 320 at the
exterior of the first shield gas injection tube 320. This
arrangement allows the injection of an oxidation gas g.sub.o to
react with the fuel gas g.sub.f, which is injected from the first
source material gas injection tube 310. Oxygen maybe used as the
oxidation gas g.sub.o.
[0042] The second shield gas injection tube 340 is disposed
coaxially with the first oxidation gas injection tube 330 at the
exterior of the first oxidation gas injection tube 330. This is
arrangement allows the injection of a shield gas g.sub.s to prevent
the particles produced by the combustion reaction of the oxidation
gas g.sub.o, which is injected from the first oxidation gas
injection tube 330, and the fuel gas g.sub.f, which is injected
from the second source material gas injection tube 350, from
sticking to the end of the injection tube 350.
[0043] The second source material gas injection tube 350 is
disposed coaxially with the second shield gas injection tube 340 at
the exterior of the second shield gas injection tube 340. The
injection tube 350 is used for injecting a fuel gas g.sub.f, a
source material S to be mixed with the fuel gas g.sub.f, and a
dilution gas g.sub.d to control the temperature of the flame, which
is generated by the combustion of the fuel gas g.sub.f.
[0044] The third shield gas injection tube 360 is disposed
coaxially with the second source material gas injection tube 350 at
the exterior of the second source material gas injection tube 350.
This arrangement allows the injection of a shield gas g.sub.s to
prevent particles produced by the combustion reaction of the fuel
gas g.sub.f, which is injected from the second source material gas
injection tube 350, and the oxidation gas g.sub.o, from sticking to
the end of the injection tube 350.
[0045] The second oxidation gas injection tube 370 is disposed
coaxially with the third shield gas injection tube 360 at the
exterior of the third shield gas injection tube 360. This
arrangement allows the injection of an oxidation gas g.sub.o to
react with the fuel gas g.sub.f, which is injected from the second
source material gas injection tube 350.
[0046] The co-flow diffusion flame burner device 300 according to
the second preferred embodiment of the present invention generates
double flames, by which glass soot can be formed. Therefore, it is
possible to deposit uniformly thin layers over a broader area.
[0047] Furthermore, by providing additional shield gas injection
tubes, source material gas injection tubes, and oxidation gas
injection tubes to the construction of the co-flow diffusion flame
burner 300 according to the second preferred embodiment of the
present invention, a co-flow diffusion multiple flames burner, that
can generate multiple flames, can be obtained.
[0048] As described above, the co-flow diffusion flame burner
according to the present invention can produce glass soot with a
reduced particle size and uniform particle size distribution,
thereby depositing the glass soot uniformly over a broader
area.
[0049] While this invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not
limited to the disclosed embodiment; to the contrary, it is
intended to cover various modifications within the spirit and scope
of the appended claims.
* * * * *