Note: Descriptions are shown in the official language in which they were submitted.
13~
,
METHODS OF AND APPARATUS FOR ADJUSTING OPTICAL FIBER
CONNECTOR COMPONENTS AND PRODUCTS PRODUCED THEREBY
Technical Field
This invention relates to methods of and apparatus
for adjusting optical fiber connector components and
products produced thereby. More particularly, this
invention relates to post molding methods and apparatus for
adjusting an alignment sleeve and/or optical fiber
terminating plugs so that when the plugs are mounted in the
sleeve, the fibers are aligned and have a predetermined end
separation.
~ Background of the Invention
; The use of optical fibers in communications is
growing at an unprecedented rate. Low loss fibers which
~- are produced by any one of several techniques may be
-~ assembled into ribbons which are then assembled into
cables, or stranded into cables, or they may be enclosed
singularly in a jacket and used in various ways in a
central office, for example.
In order to assure that the low loss fibers which
are produced today are not diminished in their
effectiveness in systems, the fibers must be connected
through intermateable connectors which preserve those low
; 25 losses. For fiber ribbons, connectors comprise grooved
chips which hold a plurality of fibers of one ribbon in
alignment with fibers of another ribbon. Such a connector
is shown for example in U. S. patent 3,864,018 which issued
on February 4, 1975 in the name of C. M. Miller.
For single fiber cablesr connections may be made
through a connector which is referred to as a biconic
connector. See U. S. patent 4,107,242 which issued on
August 15, 1978 in the name of P. K. Runge. That connector
includes a housing in which is mounted a biconic alignment
sleeve. The sleeve includes two truncated, conically
shaped cavities which communicate with each other through a
~ common plane which has the least diameter of each cavityO
:~
- ;, : ...- ~ -
- . . .
.- : : -- - , . .
-- 2 --
Each of two fibers to be connected is terminated with a
plug comprising a primary pedestal or truncated, conically
shaped end which is adapted to be received in one of the
cavities of the sleeve. At least portions of the conically
shaped surfaces of the plug ,and of the sleeve serve as
alignment surfaces and are intended to be conformable. The
fiber extends through the plug and has an end which
terminates in a secondary pedestal of the plug. A
cylindrically shaped portion of the plug is connected to
the truncated end. The plug is urged into seated
engagement with the wall defining the cavity in which it is
received.
Minimal loss between the connected fibers is
achieved when the fibers which are terminated by the plugs
are aligned coaxially and when the fiber end faces, each of
which is planar, contact in a common plane. Considering
the size of the fibers, for example one with a core
diameter of 8 microns and a cladding diameter of ~25
microns, the task of providing conformable, conical plug
and sleeve surfaces in order to meet alignment and end
separation requirements is a formidable one. Further, this
task is made difficult by the somewhat imprecise surface
tolerances which are achieved when molding the alignment
sleeve.
The alignment sleeves as molded are checked for
accuracy by inserting a guaging ball into each cavity and
measuring the distance between reference circumferences of
the walls of opposing cavities which are engaged by the
balls. If the distance is too long, the plugs may seat
within the cavities, but the end separation of the fiber
end faces is too great. On the other hand, if the distance
is too short. the secondary pedestals touch, but there is
insufficient contact between the alignment surface.
Further, if the fiber end faces contact each other prior to
seating the conformable portions of the alignment surfaces
of the plugs, the fibers within the plugs may become
misaligned or the fiber end faces may become damaged. It
~2~35
-- 3 --
has been very difficult to obtain simultaneously seating of
the plugs in the sleeve cavities and end face contact of
the fibers. In the past, an undesirably high number of
sleeves have exhibited distances which were not within
acceptable tolerance levels.
A problem also exists with respect to a so-called
taper length of the plug. The plug taper length is defined
as that distance from a reference circumference on the plug
boundary to the terminated fiber end face which is the end
face of the secondary pedestal. The initial adjustment of
the taper length is accomplished with methods and apparatus
disclosed in U. S. patent 4,384,431 which issued on
May 24, 1983 in the name of K. W. Jackson. However, if the
taper length is too long, the secondary pedestals may touch
but there is no contact between the conforming surfaces.
On the other hand, if the taper length is too short, the
plugs seat within the cavities of the sleeve, but the end
faces of the fibers are spaced apart by too great a
distance.
The prior art does not provide an altogether
satisfactory solution. For example, in one patent, a
quantity of index matching optical fluid is positioned
within the cavities of the sleeve, after which the fibers
are pushed into the cavities until their end faces engage
the conically shaped walls to align the fibers and to place
their end faces in close adjacency. The optical fluid
helps to reduce the transmission loss notwithstanding the
fact that the end faces are not contacting. Although this
arrangement may provide an ade~uate connection, it depends
on an additional medium which may introduce contaminants at
the fiber junction.
Seemingly, the prior art is devoid of a simple
solution to the problem of providing production sleeves and
plugs at a relatively high yield for biconic connectors
which may be used for multi or single mode lightguide
fibers. Desirably, the solution does not involve
additional elements or time in the connection procedures,
- :
127(~35
but instead involves an ad~ustment of the high production
yield~ molded sleeves and plugs to achieve precision
without the need of a skilled machinist.
Summary of the Invention
The foregoing problems have been solved by the
methods and apparatus of this invention. A method is
provided to adjust associated, conically shaped alignment
surfaces of a plug, which terminates an optical fiber, and
of a sleeve, which is adapted to receive the plug, to cause
an end face of the fiber to occupy a pre-determined
position when the plug is received in the sleeve. The
- method includes the steps of juxtaposing one of the
associated alignment surfaces of the plug and the sleeve,
and a tool. An abrasive material is caused to be
interposed between the tool and the one alignment surface
and in contact with the one alignment surface. Relative
motion is caused between the tool and the one surface to
cause the abrasive material to abrade the one surface to
adjust the distance between a reference circumference of
the one surface and a reference plane and cause the end
face of the fiber to occupy a predetermined position with
respect to the reference plane when the plug is received in
the sleeve.
In another embodiment, associated alignment
surfaces are used to cause a two cavity sleeve to hold the
plugs of two fibers aligned with each other and to cause
their end separation to be a predetermined amount. One of
the associated conically shaped surfaces of a first
truncated conically shaped plug which terminates an optical
fiber and of a wall which defines a conically shaped cavity
of the sleeve destined to receive the first plug is abraded
by causing relative motion between the one surface and a
tool which is provided with an abrasive material. Also,
one of associated conically shaped surfaces of a second
truncated conically shaped plug which terminates an optical
fiber and of a wall which defines the other conically
shaped cavity of the sleeve is abraded by causing relative
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motion between it and the tool. The abrading steps cause
the distance between a reference circumference of one of
the alignment surfaces of the first plug and associated
cavity wall and a reference circumference of one of the
alignment surfaces of the second plug and associated cavity
wall to be a predetermined value. This results in the
first and second plugs simultaneously being aligned
coaxially in the sleeve and the end faces of the fibers
terminated in the plugs having a predetermined separation.
In a preferred embodiment, the wall which defines
each of the sleeve cavities is abraded by a tool having a
truncated conically shaped end portion which is faced with
an abrasive material and which is provided with a lubricant.
When the tool is inserted into each cavity, its end engages
the wall of the cavity before reaching a transverse
centerline of the sleeve. Then the tool is turned rotatably
while forces are applied to the tool in a direction
parallel to a longitudinal axis of the sleeve. The tool is
turned rotatably about an axis which is substantially
coincident with the longitudinal axis of the sleeve.
The invention also includes an apparatus for
adjusting alignment surfaces on the fiber terminating plugs
and on the sleeve to cause each sleeve to hold two plugs
and the fibers aligned with each other and to cause their
end separation to be a predetermined amount. In a
- preferred embodiment, the apparatus includes tool means
- including a conically shaped truncated surface which is
provided with an abrasive material for abrading one of
associated conically shaped surfaces of a first truncated
conically shaped plug which terminates an optical fiber and
of a wall which defines a conically shaped cavity of a
sleeve destined to receive the first plug. Also, the tool
means is capable of abrading one of the associated
conically shaped surfaces of a second truncated conically
shaped plug which terminates an optical fiber and of a wall
which defines the other conically shaped cavity of the
sleeve. As a result, the distance between a reference
,, ., ~ : , . . : - . . .
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circumference of one of the alignment surfaces of the first
plug and sleeve to a reference circumference of one of the
alignment surfaces of the second plug and sleeve is a
predetermined value. The tool means is turned by hand or
by an apparatus which includes a flexible or self-aligning
: shaft about a longitudinal axis of the sleeve to cause the
~ tool to remove material from one of each pair of
: associated surfaces of the plugs and the sleeve.
Brief Description of the Drawings
Other objects and features of the present
invention will be more readily understood from the
following detailed description of specific embodiments
- thereof when read in conjunction with the accompanying
drawings, in which.
FIG. 1 shows an elevational view of a biconic
: connector for lightguide fiber cables which includes an
alignment sleeve and two plugs each of which terminates an
: optical fiber;
FIG. 1A is a detail view of a portion of a biconic
: 20 connector plug,
FIG. 1B is a detail view of a single cavity
: alignment sleeve of a connector and a plug which terminates
~ an optical fiber;
; FIG. 2 shows an arrangement for gauging the
:`: 25 seating of a plug in an alignment sleeve;
FIG. 3 is an elevational view of an alignment
sleeve with gauging balls in position to indicate end face
:: separation;
FIG. 4 is a schematic elevational view which shows
plugs inserted into an alignment sleeve as molded;
FIG. 5 is a view of a tool which is used to adjust
a sleeve;
FIG. 6 is a schematic elevational view of the
:~ plugs and the sleeve which are shown in FIG. 4 after the
sleeve has been adjusted;
: E'IG. 7 is a schematic view which shows
~ longitudinal surface profiles of a biconic sleeve surface
: . :: : ;: ., : ~ , ' , :
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-- 7 --
before and after the application of the adjustment methods
of this invention;
FIG. 8 shows ball separation characteristics for
single mode biconic sleeves before and after adjustment,
FIG~ 9 shows a sampling of losses of biconic
connections using molded sleeves which have been adjusted:
FIG. 10 is a schematic elevational view which
shows another tool such as a sleeve which is used to adjust
a plug; and
FIGS. 11A and 11B show circumferential profiles
of a biconic plug and sleeve before and after adjustment.
Detailed Description
Referring now to FIG. 1, there is shown a biconic
:` connector designed generally by the numeral 20. The
biconic connector 20 includes a housing 22 for receiving
: two plugs 24-24 each of which terminates a lightguide or
optical fiber 25. Both the plug and the housing are made
of a crushed silicar transfer molding grade epoxy
composition, for example. As can be seen in FIG. 1A, each
plug 24 includes a cylindrical portion 26 which includes a
bore 28, and an end portion 30. The end portion 30 has a
truncated conical shape and includes a passageway 32 that
communicates with the bore 28.
A coated single optical fiber 25 which has been
jacketed with a plastic material such as polyvinyl chloride
to form a cable 35 is terminated with the plug 24. The
jacketing material and the coating are removed from an end
portion 34 of the single fiber cable. The cable is
inserted into the bore 28 until the bared end portion 34 is
received in the passageway 32 with an end portion of the
fiber 25 extending into a secondary pedestal 36. An end
face of the fiber 25 is coincident with the end face of the
secondary pedestal 36. The cable at its exit from the bore
28 is provided with a strain relief member 38.
Flach plug 24 is provided with retaining rings 40
and 42. The retaining ring 40 abuts a collar 45 which is
fixedly located about the plug 24. A compression spring
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44 is disposed about the cylindrical portion 26 of the plug
between the collar 45 and a collar 47. The plug 24 is
positioned in an end portion of a threaded holder 46 with
the collar 47 in engagement with an annular lip 48 interior
to the holder. The retaining ring 42 is disposed about the
cylindrical portion 26 of the plug 24 on the other side of
the lip 48 to hold the plug within the holder. A threaded
portion 5~ extends from the hol~er 46 and the single fiber
cable 35 extends in the other direction from within the
holder 46.
A center portion 56 of the housing 22 is adapted
to receive the two threaded plug holders and two plugs 24-
24. The center portion 56 includes two opposed internally
threaded cavities 58-58 and a flange 60 adapted to be
mounted to a supporting surface. The flange 60 is aligned
with an internally disposed annular collar 62 which extends
toward a longitudinal axis 64 of the housing. The center
-~ portion 56 of the housing also is adapted to receive an
alignment sleeve 66 which comprises two opposed truncated,
conically shaped cavities 68 and 70 which meet at a common
plane 72.
The alignment sleeve 66 is disposed within the
portion 56 of the housing so that when the plugs 24-24 are
mounted in the holders 46-46 and the threaded portions 54-
54 turned into the cavities 58-58, the ends 30-30 of the
plugs are received in the cavities 68 and 70 with the
secondary pedestals in the vicinity of the common plane 72.
Also, as the threaded portions 54-54 are turned into the
housing portion 56, the plug portions 26-26 are moved
through the openings defined by the lips 48-48 to move the
retaining rings 42-42 out of engagement with the lips (see
left side of FIG. 1). The retaining ring 40 of the left
plug as viewed in FIG. 1 is adjacent to a sleeve retaining
ring 74. The spring 44 causes the plug end pGrtion 3n to
be seated firmly in engagement with a wall 76 of the
alignment sleeve~ The ring 74 ls threadably secured inside
the housing portion 56 and although not necessarily in
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engagement with the sleeve, it prevents the sleeve from
being removed inadvertently from the housing. Further, the
right plug end 30 as viewed in FIG. 1 is moved into the
cavity 68 of the sleeve 66 and contacts a wall 78. The
sleeve 66 may float within an opening 79 in the collar 62
to facilitate alignment of the two plugs 24-24.
In another embodiment, a sleeve 80 (see FIG. 1B)
which resembles half of a sleeve 66 is used to connect a
plug 24 to a device 81. For that arrangement, the end of
the optical fiber must be aligned coaxially with the sleeve
80 and with a connective portion of the device 81 and have
a predetermined separation with respect thereto.
Ideally, to achieve minimum loss, the plugs 24-24
disposed within the sleeve 66 should have their
longitudinal axes aligned and end faces of the fibers
within the secondary pedestals 36-36 contacting each other
or at worst spaced apart a slight predetermined distance.
The outer surface of the conical end 30 of each plug 24 and
the surfaces of the walls 76 and 78 of the sleeve cavities
are associated alignment surfaces which are intended to
cause the desired positioning of the pedestals 36-36 when
the conical ends of the plugs are received in the sleeve
66. The problem is that the alignment sleeves 66-66 as
provided by transfer molding apparatus, for e~ample, are
not made within tolerances which result in the plugs 24-24
being aligned and having the required end separation in a
considerable percent of the product.
In order to achieve the specified requirements,
the sum of the distances from the common plane 72 to a
reference circumference of the cavity 70 and a reference
circumference of the cavity 68 must be in a predetermined
range. Likewise a so-called taper length of each plug must
be a predetermined distance. As will be recalled, the plug
taper length is defined as the distance from a reference
circumference on the plug boundary to the end face of the
secondary pedestal 36. Testing procedures have been
~;~ developed for determining the taper length of a plug for a
-
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-- 1 o --
biconic connector and for checking the distance between the
reference circumferences of the sleeve.
Referring now to FIG. 2, there is shown an
apparatus 82 which is used to measure the plug taper
length. When a metallic gauging ball 83 is inserted into a
metallic gauging sleeve 84, the ball projects from a
reference circumference of the sleeve at a location 86 a
predetermined distance TL, which is referred to as the
taper length and which may b,e monitored. The reference
circumference is the circumference of the location where
the ball 83 contacts the sleeve cavity wall. When a plug
- 24 is inserted into the gauging sleeve 84, the end of its
secondary pedestal 36 may be above, at, or below a plane 87
through the end of the gauging ball. This determination is
indicative of whether or not the plug taper length is too
short, acceptable or too long.
A similar test also has been developed for
checking alignment sleeves to determine whether the
distance between reference circumferences of the sleeve is
within a predetermined tolerance. This is accomplished as
seen in FIG. 3 by inserting gauging balls 88 and 89, which
are made of a suitable material, such as metal or ceramic
material, for example, into each cavity of a sleeve 66.
Then a distance "d" between the reference circumferences 91
and 92 where the balls 88 and 89 engage the walls of the
cavities 70 and 68 of the sleeve 66 is measured and
compared to a standard value. It has been found that an
unacceptable number of the sleeves 66-66, as molded, have
distances between reference circumferences which are not
within the tolerance range. As a result, the gauging balls
88 and 89 generally are spaced farther apart or closer
together than required which results in plug ends, and
therefore fiber end faces, being spaced too far apart or
the fiber ends perhaps being misaligned or both.
As should be apparent, the problem of end face
separation and alignment in biconic connectors is twofold.
First, the sleeve cavities 68 and 70 themselves must meet
-
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.
~ ;~'70135
- 11 -
precise configurations. Secondly. the plugs 24-24 each
must have a taper length which is a predetermined value.
The methods of this invention are used to solve both
problems and provide plugs and sleeves which mate in a
manner to provide a desired fiber end face separation and
fiber alignment. This is accomplished by causing at least
those portions of the outer surface of the conical ends 30-
30 of the plugs 24-24 and the walls 76 and 78 of the
sleeves 66-66 which are adjacent to the common plane 72 to
be substantially conformable. It should be clear that
those sleeves, as molded. in which the gauging balls are
too close together are not able to be adjusted.
An enlarged view of an alignment sleeve, as
molded, with two plugs 24-24 received therein is shown in
FIG. 4. The sleeve ~6 is molded and the plugs are molded
so that when the plug 24 is inserted into the sleeve 66, it
engages the cavity wall to one side of the common plane 72
as is shown in an exaggerated fashion in FIG. 4. The
common plane 72, as will be recalled,. coincides with a
transverse axis 98 through the center of the sleeve 66. As
can be seen, the end faces of the pedestals 36-36 and hence
the end faces of the lightguide fibers which are terminated
by the plugs 24-24 are spaced apart, farther in fact than
~, allowed. Also, the surfaces of the plugs and sleeves have
different included angles which are exaggerated in FIG. 4
for purposes of clarity.
Referring now to FIG. 5, there is shown
schematically an apparatus for providing post molding
adjustments to a sleeve 66. The apparatus includes a tool
-30 100. The tool 100 includes a tapered portion 104. The
tapered portion 104 has a precisely machined configuration
~ which is a truncated conical shape. Further, the tool 100
;;' is faced with an abrasive material 105, such as, for
; example, diamond particles in a nickel matrix, which is
plated to the surface of the tapered portion of the tool.
The tool 100 is adapted to be turned rotatably by
a cylindrical portion 102 about a lonyitudinal axis 106.
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In a preferred embodiment, the axis 106 is not fixed by
mounting the tool. Rather the tool 100 and portion 102 are
hand held and free to float to find a center of rotation,
preferably at the center of a plane slightly to one side of
the common plane 72. If mounted about a fixed axis of
rotation, any error could be multiplied unless the axis of
rotation is prealigned with the center of the sleeve in the
vicinity of the common plane 72. In the alternative, the
tool could be mounted on a flexible spindle instead of
being hand held.
The tool 100 has a particular configuration. For
example, the tapered portion 104 has a minimum diameter
which is slightly greater than the diameter of the sleeve
66 along the common plane 72. As a result, the tool 100
engages a wall of each cavity to one side of the common
plane 72. Because of molding flash, the circumference of
the sleeve cavities along the common plane is not well
defined. If the end of the tool 100 were bottomed out at
the minimum diameter, its axis of rotation would be
` 20 affected adversely.
This is arranged so that when the tool is rotated,
its axis of rotation 106 is coincident with that of the
cavity into which the tool has been inserted near the
center of the common plane 72 of the sleeve. This is
important inasmuch as this is the region where the fiber
end faces either touch or are spaced apart. If the axis of
rotation were to be determined at a distance spaced from
the center of the sleeve 66, any error in finishing or
molding could be propagated and multiplied undesirably as
the common plane 72 is reached, which would affect
- adversely the critical region.
Another important parameter with respect to the
tool is an angle ~ , which is the included angle between
~`~ the line of revolution of the conically shaped end at
diametrically opposite positions. Typicallyr the sleeve 66
as molded has an included angle ~ which is in the range of
about 20. The tool end has an included angle which is
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12~135
- 13 -
slightly less and which is in the low end of the range for
that of the cavity.
In operation, a sleeve which intentionally has
been molded with a distance "d" slightly longer than
desired is held in a support (not shown). The tool 100 is
coated with a lubricant such as alcohol, for example, and
inserted into each end of the sleeve 66 until it bottoms
out in the vicinity of the common plane 72 (see FIG. 5).
Relative motion is caused to occur between the tool 100 and
the sleeve 66 by turning the portion 102 of the tool, by
turning the sleeve 66, or by turning both. In a preferred
embodiment, the tool 100 is caused to be turned rotatably
about the axis 106 of the sleeve 66 to cause the abrasive
mataerial to engage and remove material form the wall of
the sleeve which defines each cavity. If the tool 100 is
hand held, it is turned in opposite rotary directions by
finger motion while a force, F, is applied in a direction
parallel to the axis 106 (see FIG. 5).
Because material is removed from each cavity wall,
the gauging balls 88 and 89 when inserted, will become
disposed closer together. Material is removed from the
walls defining the cavities until the alignment surfaces of
the plugs 24-24 and of the sleeve 66 are substantially
conformable (see FIG. 6), at least adjacent to the common
plane 72. The relative motion is caused to occur until the
distance between a reference circumEerence of the cavity 68
to a reference circumference of the cavity 70 is within a
predetermined range. As will be recalled, the reference
~ circumference of each cavity is that circumference along
; 30 which the cavity wall is contacted by a gauging ball. For
a single cavity sleeve (see FIG. 1B) such as might be used
to connect a cable to a device, for example, the adjustment
is carried out until the distance from a reference
circumference to a reference plane, which may be the plane
72, is a predetermined value. This insures a desired
simultaneous fiber end face separation and centering
registration. Also r it should be pointed out that this
3~
- 14 -
technique has increased substantially the production yield
of acceptable sleeves.
Afterwards, a lint-free cloth is used to apply
alcohol to the cavity surfaces to clean them. Then the
cavity surfaces are dried with a jet stream o~ air and with
the same lint-free cloth. In a next step, the cavity walls
of the sleeve are polished with an antistatic, dust
repellent material. Then it is cleaned, air-dried, cleaned
with alcohol, redried and cleaned with a lint-free cloth.
It should be realized that the tool 100 could
comprise a plug 24 which is provided with an abrasive
material. Also, it should be apparent that a tool could be
juxtaposed to the conical surface of the cavity 68 or 70
and an abrasive medium interposed between the tool and the
cavity surface and in contact with the cavity surface. The
relative motion causes the distance between the two
reference circumferences to decrease. A suitable abrasive
medium which may be interposed between the surfaces is an
aluminum oxide in a water-alcohol carrier, for example.
~ 20 Further, the same tool 100 is used to adjust both
`~ cavities. This results in the cavities 68 and 70 being
matched, which is not necessarily true following molding.
Going now to FIG. 7, there is shown a profile 110
of a sleeve 66 after it is molded, then cured, and a
profile 115 after it has been adjusted by the conformable
lapping technique of this invention. Each profile is taken
over the length of the tapered portion of the sleeve. As
can be seen in FIG. 7, the conformable lapping technique
produces a profile 115 which is substantially smoother and
` 30 more straight than that of the connector component in the
as molded condition.
; FIG. 8 is even more telltale of the results
achieved by the methods and apparatus of this invention.
In FIG. 8, points designated 120 and located above a
horizontal line 122 show gauging ball separation of a
number of sample sleeves 66-66 prior to the application of
the methods of this invention. After the sleeves 66~66
., : : ;, . :
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- 15 -
have been adjusted, the range of ball separation is lowered
substantially as is evidenced from the plotting of points
126-126 between the two horizontal lines 122 and 124. In
FIG. 9, points 128~128 show the losses encountered with
single mode fibers connected with sleeves 66-66 after the
sleeves have been micro-adjusted in accordance with this
invention.
Viewing now FIG. 10, there is shown an
arrangement of a tool 130 which is used to adjust the taper
length of a plug 24. The tool 130 includes a cavity 132
which is machined to have a precise truncated conical shape
and which is faced with an abrasive material 134 such as
that whic~ is used to face the tool 100 of FIG. 5. A plug
24 having a less than required taper length is dipped in
alcohol and inserted into the cavity 132 of the tool 130
and turned rotatably while a longitudinal force F is
applied. This causes material to be removed from the
surface of the plug and results in a longer taper length.
It should be apparent that the tool 130 could comprise a
sleeve 66 having cavity walls which have been faced with an
- abrasive material. Afterwards, the plug is cleaned and
dried and polished as described with respect to the sleeve
adjustment.
This last-mentioned technique facilitates the
repair of damaged plug-terminated fibers. In the event
~hat the fiber end in the secondary pedestal 36 becomes
~; scratched inadvertently, the end of the pedestal is
refinished which thereby reduces the taper length
measurement. The required taper length is reachieved by
inserting the plug 24 into a tool sleeve having its
cavities lined with the abrasive material and turning
rotatably the plug while applying a longitudinal force F
thereto.
~ The adjustment of the plug 24 also causes removal
; 35 of the sharp leading edge of the plug end portion 30. As a
result, damage to the sleeve 66 during insertion is reduced
substantially.
.: .,.- - - -:
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~L2'7~13~ii
- 16 -
This technique improves the longitudlnal surface
profile of the plug and the roundness of its
circumferential surace. The profiles shown in FIG. 7 also
apply to plugs which are adjusted in accordance with this
invention. The improvement in roundness of the sleeve
cavity wal.ls or of the plug conical surface is shown by
comparing FIGS. 11A and 11B. Radial lines 140-140 shown in
FIGS. 11A and 11B are provided for graphing purposes. FIG.
: 11A and 11B are provided for graphing purposes. FIG. 11A
10 shows circumferential profiles 141 and 142 o a sleeve
cavity wall or of a plug outer surface on charts 144-144
before adjustment and FIG. 11B shows their configurations
141' and 142' afterwards.
It is to be understood that the above-described
arrangements are simply illustrative of the invention.
Other arrangements may be devised by those skilled in the
art which will embody the principles of the invention and
~ fall within the scope and spirit thereof.
:
~ 25
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