Note: Descriptions are shown in the official language in which they were submitted.
~L27~
DISTRlBUTIVE COUPLERS FOR FIBER OPTICS
TECHNICAL FIELD
__
The present invention relates to a distribu-
tive coupler andg more particularly, to a distr~butive coupler useful with at least one set Or optical fibers.
EACKGROUND OF THE. PRIOR ARl'
In recent years; ~iber optic transmission lines
made up of one or more optlcally conductive fibers
arranged to form a ~lexlble cable ~or conveying light
10 from one location to another have come into increasing
use. The applications have varied although one particu-
larly signi~icant application has been conveying data
from one location to another by modulating a light
source wlth data to be transmltted at one end o~ the
cable and recovering the data at the other end of the
cable by a photosensitive detector. Since the data is
conveyed by a medium not subject to radio frequency
inter~erence or detection, ~iber optic transmission
lines are particularly well adapted ~or applications
requiring a high degree o~ security llke those ~ound in
the data processlng field.
Wlth the increasing use of fiber optic trans-
mis~ion lines; the need developed ~or connectors cap-
able o~ ~oining segments Or cables with mlnlmum detriment
to the optical transmission path. It has been ~ound
that precise axial~ angular and lateral alignment be-
tween a palr of flber optic cables can be achieved by
terminating the optical fibers of the cables in con-
nector pin assemblies in such a way as ko provide
concentric aligntnen~ with respect to the outer dimen-
sions of the connector pins. When a palr o~ connector
pins are concentrically and accurately aligned, the
ultlmate result is that the optical ~ibers will likewlse
be axially, angularly and laterally aligned for e~fi-
cient light transfer.
While the connector art is still developing,connector pln assemblies are available today for ter-
minating the optlcal ~ibers of the cables so that they
are concentrically and accurately aligned within
accepted tolerances. More recently, there has been
~2~ g
- ~ -
a growlng interest in, and recogn:ltlon o;~ the need forg
developing sultable d-Lstributive couplers f'or dis-
tributing light among ~iber optlc transmission lines
so that one or two way communicatlon ls possible f`rom
any one or more optical flbers of a set of optical
flbers to all of the optical fibers of the same or a
dl~ferent set of' optical ~ibers. This interest has
been spawned primarily b~ the need to distribute an
optical signal to a plurality of locations~ More par-
10 ticularly, distribut~ve couplers have been sought whichoperate in the manner described while producing sub-
stantially uniform illuminatlon of an entire set of
optlcal fibers utilizirlg the light transmitted through
any one or more optical f'lbers ~1ithout excessive loss
15 of light or excessive distortion of light signal
pulse~. Additlonally, a distributive coupler `nas been
needed to make it possible to easily adjust the optical
components for use wlth different types of` optical
~ibers and dlr~erent plurallties o~ opt~cal ~ibers ~n a
20 manner capable of' fabrication at reasonable cost and
to acceptable kolerances.
BRIEF SUMMARY OF THE INVENTION
Accordlngly~ the present inventiong ln a broad
aspect, is d-lrected to a dlstrlbutive coupler for use
25 with at least one set o~ optical ~lbers. It includes
means ~or supporting the end port~ons ~f ~he ~ptical
fibers5 means for directing light transmitted through
any one or more of the optlcal ~ibers onto an entire
set o~ optical ~ibers, and means ~or adjusting the
30 position of the light directing means relative to the
~iber supporting means. With these ~eatures of con-
structiong the distr-ibutive coupler produces substan-
tially uniform lllumination o~ all of the optical f`lbers
o~ the entire set of` optical fibers.
More specif'icatllyg the coupler lncludes a
~iber optic terminal f'or supporting the end portions o~
each set of optlcal f`ibers. ln a ref'lective mode) the
coupler is adapted ~or use with one set Or optical
~ibers by directing light transmitted throu~h any one
--3--
or more of the optical fibers back onto the set of
optical fibers. A reflectlng e].ement is utilized to
reflect transmitted light toward the set of optical
fibers and a focusing element is utilized to focus re-
flected light onto tl1e set of optical fibers. In atransmissive mode, the coupler is adapted for use with
two sets of optical ~ibers by directing light trans-
mitted through any one or more of the optical fibers
onto the other set of optical fibers. A shaping element
10 is utiliæed for shaping light transmitted toward the
other set of optical fibers and a focusing element is
utilized for focusing transmitted light onto the other
set of optical fLbers. The coupler also lncludes
telescoping houslng segments for adjusting the position
of the optical elements relative to each fiber optic
terminal.
In the re~lective mode, the distributive
coupler includes means for supporting the end portions
of the optical fibers of one set o~ optical flbers. It
20 also includes means ~or directing l-lght transmitted
through any one or more of the opt'lcal fibers onto the
set of optlcal fibers wherein the :Light directing means
for this mode includes means ~or reflecting transmitted
light toward the set o~ optlcal fibers and means for
25 focusing reflected li~ht onto the set o~' optical ~lbers
with the light focusing means being disposed between
the riber supporting means and the light re~lecting
means. Further~ the reflective mode distribut~ve
coupler inc].udes means for adjusting the position of
30 the light directing means relat~ve to the riber support-
lng means to produce substantlally uniform illumination
of the set of optical fibers
Additional deta-lls of the reflective mode
distributive coupler include a housing having first and
35 second housing segments telescopically related to one
another so as to de~ine at least a portlon o~ the posi-
tion adjusting means. Preferabl~, the f~rst and second
housing segments are complementarily shaped having a
common longitudinal axis and include means for support-
. .
.. . : .
, .
`, ~,
--4---lng the llght focusing means or lens and the light
reflecting means or mirror in spaced apart relation
within the housing. Advantageously, the light focusing
means or lens is supported in one of the housing seg-
ments and the light reflecting means or mirror issupported in the other of the housing segments so as to
be movable toward and away from the light focusing
means or lens by utllizing the portion of the position
adJusting means permitting the housing segments to be
lQ moved telescopically relative to one anokher. In addi-
tion, the reflective mode distributive coupler includes
a fiber optic terminal having a sleeve supporting the
end portions of the optical fibers of the set of optl-
cal fibers in tightly packed relation parallel to one
15 another thereby definlng light transmission paths
extending parallel to the common longitudinal axis of
the housing segments.
In the transmi.ssive mode, the distributive
coupler includes means for support-lng the end portions
20 o~ the optical fibers o~ two sets of optical fibers in
spaced relation to one another~ It also includes means
for directlng light transmitted th:rough any one or more
of the optlcal flbers onto the other set o~ optical
fLbers wherein the light directlng means for thls mode
lncludes means for shaping llght transmitted from one
set of optical ~ibers and means for focus-Lng transmitted
light onto the other set of optical fibers. Further,
the transmissive mode distribu~ive coupler includes
means for adjusting the position of the light directing
30 means relative to the fiber supporting means to produce
substantially uniform illum-lnation of the other set:of
optical ~ibers.
Add~tional details of the transmissive mode
distributive coupler also include a housing having
35 ~irst and second houslng segments telescopically related
to one another so as to define at leas~ a portion of the
posi~ion adJusting means. Pre~erably~ the first and
second housing segments are complernentarily shaped
having a common longitudinal a~is and include means
.. :
7~3~9
for supporting ~he light shaping means or lens and the light
focusing means or lens within the housing. Advantageously, the
light shaping means or lens is supported in one o-f the housing
segments and the light focusing means or lens is supported in
the other of the housing segments so as to be movable toward and
away from the light shaping means or lens by utilizing the
portion of the position adjusting means permitting the housing
segments to be moved telescopically relative to one another.
In addition, the transmissive mode distributive coupler also
includes a fiber optic terminal associated with each of the
housing segments each of which includes a sleeve supporting the
end portions of the optical Eibers of one of the sets of optical
fibers in tightly packed relation parallel to one another there-
by defining light transmission paths extending parallel to the
common longitudinal axis of the housing segments.
The invention is particularly directed toward a dis-
tributive coupler for coupling light between at least one opti-
cal fiber and a set of optical fibers. The coupler comprises
means for suppor-ting one optical fiber and a set of optical
fibers and means for directing light transmitted through the
one optical fiber toward the set of optical fibers ? the trans-
mitted light being directed along a light transmission path.
Means are provided for readily adjusting the directing means
axially of the light transmission path for adjusting the length
of the light transmission path to enable the light directing
means to direct the transmitted light uniformly onto all of the
optical fibers of the set.
The present invention is therefore directed to a
distributive coupler for distributing light among fiber optic
transmission lines so that one or two way communication is
possible from any one or more optical fibers of a set of optical
fibers to all of the optical fibers of ~he same or a different
,~ -5-
set of optical,fibers. It is a further object of the invention
to provide a coupler capable of distributing an optical signal
to a plurality of locations while operating to produce sub-
stantially uniform illumination of an entire set of optical
fibers utilizing the light transmitted through any one or more
optical fibers without excessive loss of light or excessive dis-
tortion of light signal pulses. It is still a further object of
the invention to provide a distributive coupler which facilitates
easy adjustment of the optical components for use with different
types of optical fibers and different pluralities of optical
fibers in a manner capable of fabrication at reasonable cost
and to acceptable tolerances. Other objects and advantages of
the present invention will be appreciated from a consideration
of the details of construction and
-Sa-
~lZ'7~
operation s0t forth in the accompanying specificatioD, claims
and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features of the present invention are set
forth with particularity in the appended claims The invention,
together with the further objects and advantages thereof, may
best be understood by reference to the following description
taken in conjunction with the accompanying drawings. In the
drawings, like reference numerals identify like elements in the
several figures, in which:
Figure 1 is a sectional view of a reflective mode
distributive coupler constructed in accordance with the present
invention;
Figure 2 is a sectional view of an alternative embodi-
ment of a reflective mode distributive coupler constructed in ~ ;
accordance with the present invention;
Figure 3 is an enlarged end view of a fiber opticterminal sleeve taken on the linè 3-3 of Figure 2;
Figure 4 is a sectional view of a transmissive mode
distributive coupler constructed iD accordance with the present
invention; and
Figure 5 is an elevational view of a transmissive
mode distributive coupler constructed in accordance with the
present invention.
DETAILED DESCRIPTION OF THE INVENTION -`
.
In the illustrations given, the reference numerals
lO, lO' and 100 desigDate several embodiments of a distributive
coupler in accordance with the present invention. In each of
the embodiments, the coupler is adapted for use with at least
one set 12 of optical fibers 14 and iDcludes means 16 for
supporting the end portions of the optical fibers 14 and means
18 for directing light transmitted through any one or more of
--6--
~;27~
the optical fibers 14 onto the entire set 12 o~ optical fibers
14, The coupler 10 further includes means 20 for adjusting
the position of the light directing means 18 relative to the
fiber suppor*ing means 16 to produce substantially uniform
illumination of the entire set 12 o~ optical fibers 14.
In a reflective mode (as shown in Figure 1), the
distributive coupler 10 is adapted ~or use with one set 12 of
optical fibers 14 to direct light transmitted through any one
or more o~ the optical fibers 14 back onto the set 12 o~ opti-
cal fibers. The reflective mode distributive coupler 10 in-
cludes a single fiber supporting means 16. It also includes
light directing means 18 wherein the light directing means
comprise~,means 22 for reflecting transmitted light toward the
set 12 of optical fibers 14 and means 24 disposed between the
fiber supporting means 16 and the light reflecting means 22,
for focusing reflected light onto the set 12 of optical fibers
14, The reflective mode distributive coupler 10 further in-
cludes means 20 for ad~usting the position of the light direc-
ting means 18 relative to the fiber supporting means 16. With
these features of construction, the distributive coupler 10
produces substantially uniform illumination of the set 12 of
optical fibers 1~ in the reflective mode,
More particularly, the light focusing means 24 and
the light reflecting means 22 (illustrated in Figure 1) are
disposed within a housing 26 in the reflective mode coupler 10.
The housing 26 includes first and second housing segments 28
and 30 telescopically related to one ano~her and lying along a
common longitudinal aæis 32. so as to define at least a portion
of the position adjusting means 20. The first and second
hous~ng segments 28 and 30 are complementarily shaped and
include means 34 for supporting the light focusing means 2
in spaced apart relation to the light reflecting means 22
!- ~ 7-
~27~3i!3~
(described hereinafter) such that the light focusing means 24
is supported in one of the housing segments 28 and the light
reflecting means 22 is supported in the other of the housing ~ -
segments 30 so as to be movable toward and away from the light
focusing means 24 by utilizing the portion of the position
adjusting means 20 permitting the housing segments 28 and 30
to be moved telescopically relative to one
:
~ `
-7a-
anokher. The hous-lng 26 further lncludes a fiber optic
termlnal def-lning the flber supporting means 16 and
lylng along the common longitudinal axis 32 of the first
and second housing segments 28 and 30. Adva-ntageously~
the fiber optic terminal 16 includes a sleeve 38 support-
ing the end portions of the opt-Lcal fibers 14 in tlghtly
packed relatlon (as sl~own in Figure 3) such that the
end portions thereof are maintained parallel to one
another and to the common longitudinal axis 32 thereby
10 defining llght transmission paths extending parallel
to the common longitudinal axis 32 of the housing
segments 28 and 30.
Referring again to Figure 1, the sleeve 38
supports the end faces of the optical fibers 14 in
15 optical communlcation with the light focusing means 24
and the light reflecting means 22. The sleeve 38 is
advankageously associated with the one o~ the housing
segments 28 supporting the light focusing means 24 with
the llght focusing means 24 being disposed between the
li~ht reflect-lng means 22 and the end faces of the
optlcal fibers 14. Further3 the optical ribers 1l~ are
pre~erably supported such that the end faces thereof
are maintained in a plane perpendicular to the light
transmisslon paths of the optlcal fibers 14.
As illustrated in Figure 1~ the light focuslng
means 24 is a ~ocusin~ element such as a lens and the
light reflecting means 22 is a reflecting element such
as a mirror both of which are dlsposed in the light
transmission paths o~ all of the optical f-lbers 14.
The mirror 22 is movable toward and away from the end
faces of the optical fibers 14 and the lens 24 by
utilizing the portion of the position adJusting means
20 permittin~ the housing segments 28 and 30 to be
moved telescopically relative to one another, The lens
35 24 is advantageously mounted in a collar 34 within the
houslng 26 and is separately movable toward and away
from the end faces of the optical fibers 1~ so as to
define another portion of the position adjusting means
20. AdditionallyJ the housing segment 30 includes
f~Z7~8~
means 40 ~or securlng the hous-Lng segments 28 and 30
and the housing segment 28 includes means ~2 ~or
securing the collar 34 which together permit the lens
2~ and the mirror 22 to be secured in selected positions
of ad~ustment relative to the end races of the optical
fibers 14 so as to produce substantially un~form illum-
ination o~ all of the optical ~lbers 14 of the set 12
of optical fibers.
It wlll be appreciated that the lens 24 and
10 the mirror 22 (illustrated in F~gure 1) are disposed
perpendicular to the common longitudinal axis 32 and
the light transmisslon paths of the opt~cal fibers 14
with the sleeve 38 being disposed at one end 44 of the
housing 26; the mirror 22 being disposed at the other
15 end L~6 o~ the housing 26~ and the lens 24 being dis-
posed intermediate the ends 44 and 4~ of the housing 26,
The lens 24~ therefore~ divldes the housing 26 in~o two
separate chambers l~8 and 50 extending through the
housing 26 along the common longltudinal axis 32 and
20 the light transmission paths of the optical fibers 1
with the two separate chambers pre~erably being in
communlcation with one another. As will be described
more fully in connection with the alternative embodiment
of ~igure 2~ the chambers can communicate through a
25 passageway extending throu~h at least one of the housing
segments and the housing can include means ~or sealing
the chambers against exposure to conditions external
of the housing.
Re~erring again to Figure 1~ it will be appre-
30 ciated that the housing 26 is generally tubular in
shape and the housing segment 30 supports an end cap 52
at the end 46 thereof. The housing segment 30 inc~des
an annular recess 58 of a depth generally the same as
the thickness o~ the end cap 52 and o~ a diameter
35 generally the same as the diameter o~ the end cap 52.
The end cap 52 which has a central aperture 5~ is re~
tained in the annular recess 58 by any suitable securing
means such as epoxy ~as at 60). The mirror 22 is sup-
ported by the end cap 52 and need only be dimensioned
~2~
-10-
smaller than thc end cap 52 but larger than the cenkral
aperture 5~ As will be seen~ the m~rror 22 is likewise
secured to the end cap 52 by any suitable means such as
epoxy (as at 52).
As will be seen9 the long cylindrical wall 6~
of the houslng segment 30 includes a through hole 66 at
some point on the circumference. The through hole 66
is provided to accommodateg ~or exampleg a set screw L~o
defining the means for securing the telescoping housing
10 segments28 and 30 in a selected position of adjustment.
It will be appreciated that this ~acilitates movement
between the housing segments ~8 and 30 when it is
deslred to make an optical adJustment to the coupler
10. The housing segment 28 likewlse includes a cylln-
15 drical wall 68 having a through hole 70 at some pointabout the circumference provlded~ for example~ to
accommodate a set screw 42 defining the means for secur~
ing the collar 34 in a selected position of adjustment.
Wlth these features of construction~ the reflectlve
20 mode coupler 10 is well suited for produclng substan-
tlally uniform lllumination of the entire set 12 of
optical flbers utlllzlng the light transmitted through
any one or more optlcal flbers 14 hy making appropriate
adJustment ln the relatlve positlon of the optlcal
25 components 14~ 22 and 24.
Referring again to ~igure lg it will be seen
that the housing segment 28 includes a ma~or inner
diameter wall portlorl 72 and a m-lnor inner dlameter wall
portion 74, The collar 34 is mounted for sliding move-
30 ment along the common longitudinal axls 32 withln theminor inner dlameter wall portion 7L~, It will be seen
that an inwardly extending annular ~lange 76 is disposed
at the Juncture between the ma~or lnner dlameter wall
portion 72 and the minor inner dlameter wall portlon 74
35 which acts as a stop for the collar 34 restricting axial
movement of ~he collar ln a direct.lon away from the
sleeve 38. The end 4~ of the housing segment 28 in-
cludes a cap 78 which is secured to the minor inner
diameter wall portion 74 by screws (as at 80). 0~
.
78~9
course~ the cap 78 can be remov~ t~ p~ide ao~e~ ~o
khe collar 34 ~or facilltating adjustment o~ the posl-
tion of the collar 34 after loosening the set screw ~2,
As shown~ the collar 34 can be ad~usted between
a poslt~on ln which it is contacting the annular flange
76 and any other position nearer the sleeve 38 in which
lt ls still opposite the through hole 70 for securement
by the set screw 42, The collar 34 there~ora permits
~ine adJustment o~ the lens 24 so as to assure substan-
tlally uniform illumination of the entire set 12 o~optical ~ibers utilizing the light transmitted through
any one or more optical fibers 14. Further, lt will be
seen that the collar 34 includes internal threads 82
which cooperate with an externally threaded ring 84 to
secure the lens 24 within the collar 34 permltting re-
placement of the lens 24 by another lens in a ~uick and
ea~y fashion. The threaded ring 84 may simply be un-
threaded from the internally threaded collar 34~ the
lens 24 removed, and the replacemellt lens installed
into the co].lar 3~. In additiong the collar 34 can be
placed in the housing segment 28 with the lens slde o~
the collar nearer the ~leeve 38 or nearer the mirror 22
to provlde an even wlder range of ad~ustment if desired.
Re~erring to the cap 78, it includes an inter-
~5 nally threaded outwardl~ extendlng tubular port-lon 86.
The tubul~r portion 86 cooperates wlth an externally
threaded adapter 88 thereby de.~in~ng the ~iber optic
terminal 16. It will be ~een that the adapter 88 is
dlmensloned and shapsd to receive a fiber optic pin 90,
3~ which includes the sleeve 38~ through a central opening
92 thereln. It will be appreciated that the threaded
adapter 88 permits adjustment of the fiber optic pin
90 which may therea~ter be secured in a selected posi-
tion o~ ad~ustment by means o~ set ~crew 89. The ~iber
optic pin 90 also includes an outwardly extending
B annular flange ~ which cooperates with an inwardly
extendlng flange 9~:of an internally threaded nut 96.
~s shown in Flgure 1, the f~ber optic pin 90 can be
inserted into the externally thr~aded adapter 88 and the
.:
: .
39
12-
lnternally threaded nut 96 can be threaded onto the
externally threaded adapter 88 to secure the sleeve 38
in posltion w~thin the fiber optic terminal 16.
While ~orming no part o~ the present i~vention3
the optical fibers 14 comprise lead segments adapted
for connection to fiber optlc transmlssion lines. The
fiber optic connecto~s ~8 have been shown merely ~o
represent that the optlcal fibers 14 are to be connec-
ted to ~iber optic transmission lines. Ik is also
within the purview of the present invention to simply
~orm the di~trlbutive coupler with opt~cal ~ibers or
~iber optic kransmlssion lines (such as 14~ whlch are
su~ficiently long to exkend to desired receiving
stations. The optical fibers 14 could also be ~itted
with other types of connectors or spllcers to secure
the optical fibers to suitable ~iber optic transmi~sion
lines. Persons skilled in the art will readll~ recog~
nize the numerou~ means ~or ~oining the distrlbutive
coupler 10 to su~table ~lber optic transmlssion lines.
Re~errln~ to Figure 2, the alternative embodi-
ment reflective mode dlstributlve coupler 10' employs
inventlve prlnciples in oommon with the di3tributive
coupler lO of Figure l. It should be noted that cor-
re~ponding elements of the two embodiments have been
given correspond~ng re~erence numerals in the drawings
with the exceptlon that the nL~rals a~slgned to ele-
ments in the al~er~ative embodiment are prime for
purposes o~ distlnction. In order to avoid repetltion~
the distributlve coupler 10' w~ll be descr~bed only to
3 the extent it di~ers from the distributive coupler lO
with the understandlng that description of the distribu-
tive coupler 10 is otherwise equally appllcable to the
dis~ributive coupler 10'.
As will be seen, the lens 24' divides the hous-
ing 26' into two separate chambers ~8' and 50'. The
chambers 48' and 50' extend through the housing 26'
along the common lon~ltudinal axis 32' and the llght
transmission paths o~ the optical fibers 14'. The
two separate chambers 48' and 50' are in communication
~2~
with one another through a passageway 51~ extending through
the housing segment 28~, Moreover, the housing 26~ includes
means 53~ for sealing the chambers 48~ and 50~ against expos-
ure to conditions external o~ the housing 26~,
Referring again to Figure 2, it will be appreciated
that the housing segments 28~ and 30~ are generally tubular in
shape, The housing segment 30~ includes an integral end por-
tion 52~ having an internal annular ring 55'. As will be seen,
the mirror 22~ is supported against the ring 55' by any suitable
means such as epoxy (as at ~2~),
As shown, the long cylindrical wall 64~ of the hous-
ing segment 30~ includes internal threads as at 65' to co-
operate with external threads 67~ on the generally cylindrical
wall 68l of the housing segment 28~, It will be appreciated
that this de~ines the position adjusting means 20~ facilitating
telescoping movement between the housing segments 28' and 30'
when it is desired to make an optical adjustment to the coupler
10~ as well as defining the means 40' for securing the tele-
scoping housing segments 28~ and 30~ in a selected position o~
adjustment. With these ~eatures o~ construction, the coupler
10' is well suited for producing substantially uniform illumin-
ation o~ the entire set 12~ of optical fibers utilizing the
light ~ransmitted through any one or more optical fibers 14~ ~
by making appropriate adjustments in the relative position of ~ :
the optical componen~s 14', 22~ and 24~.
Referring again to Figure 2 9 it will be seen that
the housing segment 28~ includes a major inner diameter wall :;
portion 71~ and aminor inner diameter wall portion 73'. The
collar 34' is mounted along the common longitudinal axis 32
within the major inner diameter wall portion 71~. As shown,
the collar 3~ includes a through hole 75~ and a circumferential
cutout 77' through which the chamber 48' communicates with the
_, -13-
~IL27~3~9
passageway 51~ and, hence, the chamber 50i
As will be seen, the cap 78~ includes an outwardly
e~tending tubular portion 86~ The tubular portion 86~ serves
as a guide aDd support for the optical fibers 14~. It will be
appreciated that the optical fibers 14' are stripped at various
points along their lengths from the outer jacket, to the strength
members, to the inner jacket, to the fibers themselves prior to
the point the optical fibers 14~ enter the sleeve 38' The
optical fibers 14' are epo~ied in the sleeve 38~ and the tubu-
1~ lar portion 86~. Additionally, the optical fibers 14~ aresecured to the distributive coupler 10' by using a length of
heat shrink tubing 87~ extending from near the point the tubu-
lar portion 86' joins the cap 78' to rearwardly of the point
the outer jac~et is trimmed away with epoxy being used (as at
89') to secure the optical :Eibers 14' to one another, the
tubular portion 86' and the heat shrink tubing 87~,
Further details of the alternative embodiment reflec-
tive mode distributive coupler 10' include the utilization of
an 0-ring 91' between the collar 34' and the lens 24'. It is
also contemplated that the slot (not shown) in the head of the
screws 80~ and the joint between the housing segments 28~ and
30~ (as at 93') can be epo~ied, particularly for applications
requiring a hermetically sealed unit, to discp~Fage disassembly
by the user and to lock the distributive coupler into a desired
position of adjustment. If the distributive coupler 10~ is to
be hermetically sealed9 the housing segment 30~ may be un-
threaded rela$ive to the housing segment 28' until it completely
clears the 0-ring 53~, the coupler can be placed into a vacuum
for a period of time, and the vacuum chamber can be filled with
dry nitrogen immediatel~ a:Eter which the housing segment 30'
can again be threaded into position overlapping the 0-ring 53'
In a transmissive mode (as shown in Figure 4), the
-14-
~781~
distributive coupler 100 is adapted for use with two sets 12
of optical fibers 14 by directing light transmitted through
any one or more of the optical fibers 14 of one of the sets
12 o~ optical fibers onto all of the optical fibers 14 of the
other set 12 of optical fibers, The transmissive mode dis-
~ributive coupler 100 then includes means 16 at each end for
supporting the end portions of the optical fibers 14 of *he two
sets 1~ of optical fibers in spaced relation to one another.
It also includes means 18 for directing the light trans~itted
through any one or more of the optical fibers 14 of one of the
sets 12 onto all of the optical fibers 14 o~ the other of the
sets 12 wherein the light directing means 18 comprises light
shaping means 109 and light focusiDg means 110 disposed between
the sets 12 of optical ~ibers, The transmissive mode distribu-
tive coupler 100 further includes means 20 for adjusting the
position of the light directing means 18 relative to the fiber
supporting means 16. With these features of construction, the
distributive coupler 100 produces substantially uni~orm illu-
mination of the other of the sets 12 of optical fibers 14 in
the transmissi~e mode.
More particularly, the light shaping means 109 and
the light ~ocusing means 110 (illustrated in Figure 4) are
disposed within a housing 114 in the transmissive mode coupler
100. The housing 114 includes first and second housing seg-
ments 116 and 118 telescopically related to one another and
lying along a common longitudinal axis 12~ so as to define at
least a portion of the position adjusting means 20. The ~`irst
and second housing segments 116 and 11~ are complementarily
shaped and include means for supporting the light focusing
means 110 in spaced apart relation to the light shaping means
109 (described hereina~ter) such that the light ~ocusing means
110 is supported in one of the housing segments 118 and the
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8~
light shaping means 109 is supported in the other of the
housing segments 116 so as to be movable toward and away from
the light focusing means 110 by utilizing the portion of the
position zdjusting means 20 permitting the housing segments
116 and 118 to be moved telescopically relative to one another.
The housing 114 further includes a pair of fiber optic terminals
defining the fiber supporting means 16 and lying aloDg the
common longitudinal axis 120 of the first and second housing
segments 116 and 11~ with one of the fiber optic terminals 16
being associated with each of the housing segments 116 and
11~ so as to be disposed at opposite ends 130 and 132 of the
housing 114. Advantageously, the fiber optic terminals 16 each
include a sleeve 134 supporting the end portions of the optical
fibers 14 of one of the sets 12 in tightly packed relation
(similar to Figure 3) such that the end portions o~ any one
set 12 are maintained parallel to one another and to the common
longitudinal axis 120 thereby defining light transmission paths
extending parallel to the common longitudinal axis 120 of the
housing segments 116 and 118.
~e~'erring again to ~igure 4, each of the sleeves 134
supports the end faces of the optical fibers 14 ~f one of the
sets 12 in ~ptical c~munication with the light shaping means
109, the light focusing means 110 and the end faces of the
optical fibers 14 of the other of the sets 12. Both the light
shaping means 109 and the light focusing means 110 are disposed
between the end faces of the sets 12 of optical fibers wi$h the
optical fibers 14 of each of the sets being supported such that
the end faces thereof are maintained in a plane perpendicular
to the light transmission paths of the optical fibers 14,
The light shaping means 109 includes a shaping element such as
a lens and the light focusing means 110 includes a ~ocusing
element such as a lens both of which are disposed in the light
-16-
~L27~
transmission paths of all of the optical fibers 14 Both of
the lenses 109 and 110 are movable toward and away from each
other by utilizing *he portion of the position adjusting means
20 permitting the housing segments 116 and 118 to be moved
telescopically relative to one another. Further, each of the
lenses 109 and 110 is advantageously mounted in a collar 122
defining means for supporting light shaping means 109 and the
light focusing means 110 whereby the lenses 109 and 110 are
separately movable toward and away from -the end faces of the
adjacent optical fibers 14 so as to define another portion o~
the position adjusting means 20.
It will be seen that the lenses 109 and 110 are dis-
posed perpendicular to the common longitudinal axis 120 and
the light transmission paths of the optical fibers 14. Further,
the housing segment 116 includes mea~s 136 in the form of a
set screw for securing the housing segments 116 and 118 and the
housing segments 116 and 118 each include means 13~ also iD the
form of a set screw ~or securing th~e respective collars 122
which together permit the lenses 109 and 110 to be se~ured in
selected positions o~ adjustment relative to the end faces of
-the adjacent optical fibers 14 and to each other so as to
produce substantially uniform illumination o~ all of the opti~
cal fibers 14 of one of the sets 12 of optical fibers ~lore-
over, the lenses 109 and 110 are disposed intermediate the
ends 130 and 132 of the housing 114 in spaced relation to each
other and to the end faces o~ the optical fibers 14 of the sets
12 of optical fibers so as to divide the housing 114 into
three separate chambers 140, 142 and 144 extending through the
housing 114 along the common longitudinal axis 120 and the
light transmission paths. If desired, the chambers 140, 142
and 144 can communicate through ~ passageway extending through
the housing segments 116 and 118 and the housing 114 can iD-
~ ~7~
clude means for sealing th0 chambers 140, 142 and 144 against
exposure to conditions external o~ the housing 114 in the
manner taught hereinabove in connection with the reflective
mode coupler alternative embodiment of Figure 2.
Referring to Figures 4 and 5, the details of con-
struction are similar to the details of construction of Figure
1. The principal differences relate to minor changes in the
fiber supporting means 16 and the collar 122. It will be seen,
for instance, that the housing segment 116 includes an end cap
146 secured to the end 130 thereof by any suitable means such
as screws 148 and the housing segment 118 also includes an end
cap 146 secured to the end 132 thereof again by any suitable
means such as screws 148. The corresponding fiber supporting
means 16 then includes an internally threaded annular flange
member 154 secured to each of the caps 146 by means of suitable
fasteDers such as screws 156. The annular flanges 154 receive
suitable externally threaded adapters 158 which in turn are
sized and shaped to receive fiber optic pins 160. It will be
appreciated that the threaded adapters 158 permit adjustment
of the fiber optic pins 160 which may thereafter be secured in
selected positions of adjustment by means of set screws 159.
It will be seen and appreclated that the fiber optic pins 160
are secured within bores 162 extending through the threaded
adapters 158 by means of nuts 164. Of course, the fiber sup-
porting means 16 at each end of the housing 114 are advantage-
ously identical in construction to facilitate production,
Referring to the collars 122, the corresponding
lenses 109 and 110 are secured therein against radial flanges
166 by any suitable means such as epoxy (as at 170). It will
be seen that there is a stop 123 provided for the collars 122
as with the embodime~t of reflective mode distributive coupler
10 i~lustrated in Figure 1. It will be appreciated that the
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~L278~
end caps 146 can be removed, the set screws 138 loosened,
and the collars 122 moved along the common longitudinal axis
120 toward and away from the sleeves 134 in order to adjust the
positions of the lenses 109 and 110 relative to the optical
fibers 14. Likewise, the set screw 136 can be loosened to
telescopically move the housing segments 116 and 118 relative
to one another to adjust the position of the lenses 109 and 110
relative to one another all of which facilitates producing
substantially uniform illumination of all of the optical fibers
14 of a set 12 of optical fibers,
While different lenses or lens combinations can be
used in the present invention, it has been found
-18a-
7~38~
that a slngle ~ouble convex lens is well suited for a
ref~lective mode dlstrlbutive coupler and generally
plano-convex lenses are well suited for transmisslve
mode distributi~e couplers. The lenses effectively
remove the necessity o~ matchlng the size of the mixing
rods to the end face of a set o~ optlcal fibers as with
prlor art couplers, ~aslcally, the use of lenses
coupled with means for ad~usting the position o~ the
optical components renders it possible to produce
10 substantially uni~'orm illumination both in amount and
angular distribution even ~rom a non-uni~orm source.
Utilizing the features ~ the present in~en~
tion, the distrlbutive coupler can distribute the
essentially monochromatic components of llght from an~
15 optical fiber so that the amount and angular distribu~
tion of light incldent on each optical ~iber of a set
o~ optlcal fibers is equivalent to equalize slgnal
pulse shape in the fiber optic transmisslon lines after
passage through the coupler. The coupler can be ad~us-
20 ted to be used with any type o~ fiber optic cable orwith a di~ferent plurality of ~iber optic -transmlssion
lines by only changlng the d:~stances between optical
elements thereby rendering it unnecessary to change
the optical elements. With the present invention, the
25 optical elements collect~ shape and direct light in a
manner producing substantially uniform illumination o~
all o~ the optical fibers of a set of optical fibers.
With both the reflective mode and transmissive
mode distributive couplers, the ideal position for the
30 optical components can be determined ~or any particular
optical ~ibers in conventional ~ashion by mere calcu-
lation. It is also posslble to adjust the optical
components in either mode by measuring the power in the
optical ~ibers to determine when the power is essen-
35 tially equivalent in all. Additlonally, the transmls-
sive mode optlcal coupler renders adJustment o~ the
position o~ the optlcal components simple by merely
removing one angular ~lange and placing translucent
paper in its place to visually inspect the light
.
'
'
~'78~C~ .
20-
dlstrlbution,
Regardless of the manner selected for adjust-
ing the position of' the optical componentsg the present
invention provides a signl~icantly improved distribu-
tive coupler for distributing light among fiber optictransmlssion lines so that one or two way communication
is posslble from any one or more optical fibers of a
set of optical fibe~s to all of the optical fibers of
the same or a di~ferent set of optical fibers. It ls
10 clear that the objective of providing a coupler capable
of distributing an optical si~nal to a plurality of
locations has been achieved in a manner producing
substantlally uniform illumination of an entire set of
optical fibers ut~lizing the llght transmitted through
15 any one or more optical fibers without excessive loss
of light or ex~essive distortion of light signal
pulses. In addition~ the present invention provides a
distributive coupler which facilitates easy ad~ustment
of the optical omponents for use with different types
20 of optical fibers and different pluralities of optical
fibers in a manner capable O.r fabrication at reasonable
cost and to acceptable tolerances.
While in the foregoing specification a detailed
descriptiorl of the lnventive concepts have been set
25 ~orth for purposes of illustration, the details herein
given may be varied by those skilled in the art without
departing from the spirit and scope of the invention
set forth and defined by the appended claims.
