U.S. patent application number 09/821767 was filed with the patent office on 2002-01-17 for method for producing a coupler based on fiber-fused connection.
Invention is credited to Nagasaki, Hironobu.
Application Number | 20020006254 09/821767 |
Document ID | / |
Family ID | 18649381 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020006254 |
Kind Code |
A1 |
Nagasaki, Hironobu |
January 17, 2002 |
Method for producing a coupler based on fiber-fused connection
Abstract
The object of this invention is to provide a method for
producing a coupler based on fiber-fused connection which will
enable simple, rapid production of a coupler in a highly productive
manner, no matter how many optical fiber core lines may be involved
or no matter how small their diameter may be. The method consists
of placing a plurality of optical fiber cords 1,2 in parallel which
comprise optical fiber core lines 3,4 covered with jackets 7,8 with
resilient fibers 5,6 inserted between the periphery of the core
lines and the jackets; cutting a specified point of the jacket of
each optical fiber core line to divide the jacket into two limbs;
sliding the divided limbs (9,9' and 10,10' ) of the jackets in
opposite directions to expose thereby sections of the underlying
optical fiber core lines, the exposed sections of optical fibers
being brought into contact with each other, and heated to melt to
form thereby a fusion-connected section 11; sliding back each
jacket limb close to the fusion-connected section; and placing the
fusion-connected section 11 together with the inward ends of jacket
limbs in a protective case 12, a hardening resin 13 being
introduced into the cavity within the protective case 12 to fill
the cavity, and the resin being hardened to integrate the optical
fiber cords with their connection within the protective case.
Inventors: |
Nagasaki, Hironobu; (Tokyo,
JP) |
Correspondence
Address: |
ISRAEL GOPSTEIN, Esq.
Suite 200C
14301 Layhill Drive
P.O. Box 9303
Silver Spring
MD
20916-9303
US
|
Family ID: |
18649381 |
Appl. No.: |
09/821767 |
Filed: |
March 30, 2001 |
Current U.S.
Class: |
385/96 |
Current CPC
Class: |
G02B 6/2835 20130101;
G02B 6/2558 20130101 |
Class at
Publication: |
385/96 |
International
Class: |
G02B 006/255 |
Foreign Application Data
Date |
Code |
Application Number |
May 15, 2000 |
JP |
2000-142400 |
Claims
What is claimed is:
1. Method for producing a coupler based on fiber-fused connection
comprising the steps of: placing a plurality of optical fiber cords
in parallel each of which comprises an optical fiber core line with
resilient fibers disposed around its periphery, being collectively
covered with a jacket; cutting a specified point of the jacket of
each optical fiber core line to divide the jacket into two limbs;
sliding the divided limbs of each jacket in opposite directions to
expose thereby a section of the underlying optical fiber core line,
the exposed sections of the optical fibers being brought into
contact with each other, and the contacted sections being heated to
melt to form thereby a fusion-connected section; sliding back each
jacket limb close to the fusion-connected section; and placing the
fusion-connected section together with the inward ends of jacket
limbs in a protective case, a hardening resin such as an epoxy
resin being introduced into the cavity within the protective case
to fill the cavity, and the resin being hardened to integrate the
optical fiber cords within the protective case.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for producing a
coupler based on fiber-fused connection.
[0003] 2. Prior Art
[0004] Recently, with the increased spread of sophisticated
communication systems, transmission systems based on optical fibers
have been increasingly introduced for the connection of LANs and
other networks to promote OA and FA.
[0005] In a LAN based on optical fibers, optical separators and
couplers are more frequently used than before for distributing
light signals to multiple terminals and for transmitting signals in
the reverse direction.
[0006] The conventional optical separator/coupler mainly
incorporates a coupler (star coupler) having multiple input
terminals to serve as a key element of an optical data bas network.
As this communication network enables a signal transmitted from any
one terminal connected to the coupler to be distributed to the
other terminals, its application becomes increasingly widened.
[0007] The coupler as described above is conventionally fabricated
as follows. As shown in FIGS. 7 and 8, two optical fiber core lines
(a) and (b) are closely placed together to bring their clads at the
middle of their lengths in contact with each other; the contacted
clads are heated to melt to form a fusion-connected section (c);
jackets (d1), (d2), (d3) and (d4) are placed over the both limbs of
each of optical fiber core lines (a) and (b) being moved from their
ends (a1), (b1), (a2) and (b2), respectively; the fusion-connected
section (c) together with the four ends of jacket limbs close to it
are placed in a protective case (e); a hardening resin (f) such as
an epoxy resin is introduced into the cavity within the protective
case (e) to fill the cavity; and, when the resin is hardened, a
coupler integral with the optical fiber core lines is obtained.
[0008] Resilient fibers inserted longitudinally beneath the jackets
(d1), (d2), (d3) and (d4) and over the periphery of optical fiber
core lines (a) and (b) are represented by (g) in the figures.
[0009] However, with the conventional method for fabricating a
coupler as described above, it is necessary, after fused-connection
is performed on optical fiber core lines to be coupled, to place
tubular jackets over the limbs of the optical fiber core lines one
after another while those lines have resilient fibers disposed
around their peripheries. Therefore, fabrication based on the
conventional method is poor in workability, produces too voluminous
fusion-connected sections, and is high in the cost.
[0010] Particularly when a coupler involving multiple, small-bore
optical fiber core lines with correspondingly slender jackets is
fabricated, the fabrication requires much labor and time, and often
poses a problem in productivity. Moreover, a coupler produced by
the conventional method, if it has to be sufficiently reinforced,
becomes voluminous and expensive, while it becomes fragile when it
is left small.
SUMMARY OF THE INVENTION
[0011] This invention was derived from an attempt to meet the above
problems inherent to the conventional technique, and aims at
providing a method for fabricating a fusion-connected coupler which
enables simple, rapid production of a small, robust and inexpensive
coupler in a highly productive manner.
[0012] To attain the above object, the method for fabricating a
coupler according to this invention consists of placing a plurality
of optical fiber cords in parallel each of which comprises an
optical fiber core line covered with a jacket with resilient fibers
disposed longitudinally around the periphery of the core line
beneath the jacket; a cut is made on a specified point on the
jacket of each optical fiber core line to divide the jacket into
two limbs, and the divided limbs of each jacket are slid in
opposite directions to expose thereby the middle section of the
underlying optical fiber core line; the exposed sections of optical
core lines are brought into contact with each other; the contacted
sections are heated to melt to form thereby a fusion-connected
section; each jacket limb displaced outward is slid back close to
the fusion-connected section; the fusion-connected section together
with the cut ends of jacket limbs close to it are placed in a
protective case; a hardening resin such as an epoxy resin is
introduced into the cavity within the protective case to fill the
cavity; and, when the resin is hardened, the involved elements and
their connection are integrated within the protective case.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates the first step of the processes for
producing a fusion-connected coupler according to the method of
this invention.
[0014] FIG. 2 illustrates the second step of the same production
processes.
[0015] FIG. 3 illustrates the third step of the same production
processes.
[0016] FIG. 4 illustrates the fourth step of the same production
processes.
[0017] FIG. 5 illustrates the fifth step of the same production
processes.
[0018] FIG. 6 illustrates the final step of the same production
processes.
[0019] FIG. 7 illustrates the first step of the processes for
producing a fusion-connected coupler according to a conventional
method.
[0020] FIG. 8 illustrates the final step of the above production
processes.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The preferred embodiments of this invention will be detailed
below with reference to attached figures.
[0022] FIGS. 1 to 6 illustrate the processes for producing a
fiber-fused coupler according to this invention.
[0023] Firstly, two optical fiber cords 1 and 2 comprising optical
fiber core lines 3 and 4 having respective resilient fibers 5 and 6
running along their lengths and covered with jackets 7 and 8 are
placed in parallel as shown in FIG. 1. In the figure, the jackets 7
and 8 have their both ends cut to have a specified length, to
expose thereby the both ends of optical fiber core lines 3 and 4
and of their resilient fibers 5 and 6.
[0024] Next, as shown in FIGS. 2 and 3, the jackets 7 and 8
covering the optical fiber core lines 1 and 2 are cut at specified
levels 7c and 8c at the middle of their lengths, to be divided into
two limbs each; and the jacket limbs 9 and 9' and the jacket limbs
10 and 10' are slid in opposite directions such that the interval
between the inward ends 9a and 9'a of jacket 9, and the interval
between the inward ends 10a and 10'a of jacket 10 are sufficiently
large to allow the work necessary for connection, and the outward
ends 9b and 9'b and 10b and 10'b are in short by a sufficient
length of the outward ends (3a, 4a and 5a, 6a) of their respective
optical fiber core lines 3,4 and resilient fibers 5,6.
[0025] As seen from above and from FIGS. 1 and 2, when jackets 7
and 8 are cut at levels 7c and 8c close to the middle, and the
divided limbs of the jackets are separated by a specified distance,
the outward ends 9b and 9'b of the limbs of jacket 7 and the
outward ends 10b and 10'b of the limbs of jacket 8 are placed
inward with respect to the ends (3a, 4a and 5a, 6a) of their
respective optical fiber core lines (3,4) and resilient fibers
(5,6), to expose thereby the specific lengths of the both ends of
optical fiber core lines 3, 4 and of resilient fibers 5,6.
[0026] Then, the exposed mid-portions of optical fiber core lines 3
and 4 are brought into contact with each other as shown in FIGS. 4
and 5; the contacted portions are heated to melt to form thereby a
fusion-connected section 11; and the separated jacket limbs 9 and
9' and 10 and 10' are slid back close to the fusion-connected
section 11.
[0027] Next, the fusion-connected section 11 with the inward ends
9a and 9'a of jacket limbs 9 and 9', and the inward ends 10a and
10'a of jacket limbs 10 and 10' is placed in a protective case 12
as shown in FIG. 6; a hardening resin such as an epoxy resin 13 is
introduced into the cavity within the protective case 12 to fill
the cavity; and, when the resin hardens, the involved elements and
their connection are integrated within the protective case 12.
[0028] The resilient fibers 5, 6 may be made of any material
incorporated in a conventional optical fiber cord, such as aramid
fiber, glass fiber, copper wire, PBO fiber, etc. The jacket 7, 8
may be made of a thermoplastic resin, thermosetting resin,
UV-hardening resin, etc.
[0029] The above embodiment based on the method of this invention
for producing a fiber-fused coupler involves connecting two optical
fiber cables 1 and 2, but it may also involve connecting two
optical fiber tape cords, instead of cables. Needless to say, the
number of optical fiber cables or optical fiber tape cords to be
connected is not limited to two, but may take three or more as
desired.
[0030] The present invention has been described above, and will be
briefly summarized as follows: a plurality of optical fiber cords
are placed in parallel each of which comprises an optical fiber
core line covered with a jacket with resilient fibers inserted
between the periphery of the core line and the jacket; a cut is
made on a specified point of the jacket of each optical fiber core
line to divide the jacket into two limbs, and the divided limbs of
each jacket are moved in opposite directions to expose thereby a
section of the underlying optical fiber core line; the exposed
sections of the optical fibers are connected by fusion; each jacket
limb displaced towards the outward end and kept there is slid back
close to the fusion-connected section; the fusion-connected section
together with the inward ends of jacket limbs are placed in a
protective case; and a hardening resin is hardened to integrate the
involved elements and their connection. This methods dispenses with
the need for removal of the jacket from each optical fiber core
line during the work for connection, no matter how many small-bore
optical fiber core lines may be involved. Therefore, fabrication
based on the method of this invention will reduce a loss involved
in the labor and time required for completion of the product as
compared with the conventional method, and will ensure such
excellent productivity and workability as to enable the production
of densely integrated, robust products.
* * * * *