U.S. patent application number 15/337011 was filed with the patent office on 2018-05-03 for multicore optical fiber cable strain enhancement.
The applicant listed for this patent is THE BOEING COMPANY. Invention is credited to Frederick L. Brinlee, Brian J. Fujimori, Kenneth C. Noddings.
Application Number | 20180120500 15/337011 |
Document ID | / |
Family ID | 62021292 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180120500 |
Kind Code |
A1 |
Noddings; Kenneth C. ; et
al. |
May 3, 2018 |
MULTICORE OPTICAL FIBER CABLE STRAIN ENHANCEMENT
Abstract
An optical fiber cable assembly which includes an optical fiber
cable which includes at least a first core and a second core
positioned spaced apart from one another within a cladding
material, wherein the at least first core and the second core and
the cladding material extend in a direction of a length of the
optical fiber cable. The assembly further includes material
positioned at a predetermined location along the length of the
optical fiber cable, wherein the material is associated with the
optical fiber cable such that when the material is exposed to an
environment change, the material transmits a force onto the optical
fiber cable, changing a shape of the optical fiber cable.
Inventors: |
Noddings; Kenneth C.;
(Manhattan Beach, CA) ; Brinlee; Frederick L.;
(Hermosa Beach, CA) ; Fujimori; Brian J.;
(Torrance, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE BOEING COMPANY |
Chicago |
IL |
US |
|
|
Family ID: |
62021292 |
Appl. No.: |
15/337011 |
Filed: |
October 28, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/443 20130101;
G01K 11/32 20130101; G02B 6/3636 20130101; B64D 47/02 20130101;
G02B 7/008 20130101; G02B 6/02042 20130101; G01K 5/56 20130101;
G01K 11/3206 20130101 |
International
Class: |
G02B 6/02 20060101
G02B006/02; G02B 6/44 20060101 G02B006/44; G02B 7/00 20060101
G02B007/00; B64D 47/00 20060101 B64D047/00 |
Claims
1. An optical fiber cable assembly, comprising: an optical fiber
cable comprising at least a first core and a second core positioned
spaced apart from one another within a cladding material, wherein
the at least first core and the second core and the cladding
material extend in a direction of a length of the optical fiber
cable; and material positioned at a predetermined location along
the length of the optical fiber cable, wherein the material is
associated with the optical fiber cable such that when the material
is exposed to an environment change, the material transmits a force
onto the optical fiber cable, changing a shape of the optical fiber
cable, wherein: the material comprises a first portion with a first
side which defines a first groove having a first surface; the
material comprises a second portion with a first side which defines
a second groove having a second surface; the optical fiber cable is
positioned within the first and second grooves with the first side
of the first portion and the first side of the second portion
positioned in a facing relationship to one another; and the first
side of the first portion and the first side of the second portion
are bonded together with the optical fiber cable positioned within
the first groove bonded to the first surface of the first groove
with an adhesive and the optical fiber cable positioned within the
second groove bonded to a second surface of the second groove with
an adhesive.
2. The optical fiber cable assembly of claim 1, wherein the
material is secured to the fiber optical cable.
3. (canceled)
4. (canceled)
5. The optical fiber cable assembly of claim 1, wherein an outer
surface of the optical fiber cable bonded to the first surface of
the first groove and bonded to the second surface of the second
groove comprises the cladding material of the optical fiber cable
or a buffer material surrounding the cladding material of the
optical fiber cable.
6. The optical fiber cable assembly of claim 4, wherein the
material comprises polytetrafluoroethylene and the environment
change includes a temperature change such that with an increase in
temperature the polytetrafluoroethylene expands which results in
stretching of the optical fiber cable at the predetermined location
and a reduction in a diameter of the optical fiber cable and with a
decrease in temperature the polytetrafluoroethylene contracts which
results in contracting of the optical fiber cable at the
predetermined location and an increase in the diameter of the
optical fiber cable.
7. An optical fiber cable assembly comprising: an optical fiber
cable comprising at least a first core and a second core positioned
spaced apart from one another within a cladding material, wherein
the at least first core and the second core and the cladding
material extend in a direction of a length of the optical fiber
cable; and material positioned at a predetermined location along
the length of the optical fiber cable, wherein the material is
associated with the optical fiber cable such that when the material
is exposed to an environment change, the material transmits a force
onto the optical fiber cable, changing a shape of the optical fiber
cable, wherein: the material comprises two compositions wherein: a
first composition having a first coefficient of thermal expansion;
a second composition having a second coefficient of thermal
expansion; and the first and second compositions are secured to the
optical fiber cable.
8. The optical fiber cable assembly of claim 7, wherein: the first
composition is constructed into a first portion with a first side
which defines a first groove having a first surface; the second
composition is constructed into a second portion with a first side
which defines a second groove having a second surface; the optical
fiber cable is positioned within the first and second grooves with
the first side of the first portion and with the first side of the
second portion positioned in a facing relationship to one another;
and the first side of the first portion and the first side of the
second portion are bonded together and the optical fiber cable is
bonded to the first surface of the first groove and the optical
fiber cable is bonded to the second surface of the second
groove.
9. The optical fiber cable assembly of claim 8, wherein an outer
surface, of the optical fiber cable bonded to the first surface of
the first groove and bonded to the second surface of the second
groove, comprises the cladding material of the optical fiber cable
or a buffer material surrounding the cladding material of the
optical fiber cable.
10. The optical fiber cable assembly of claim 8, wherein; the first
coefficient of thermal expansion of the first composition is
greater than the second coefficient of thermal expansion
coefficient of the second composition; the environment change
includes: a temperature increase which results in a greater
expansion of the first composition of the first portion than an
expansion of the second composition of the second portion resulting
in bending of the first portion, the second portion and the optical
fiber cable, wherein a radius of curvature of the optical fiber
cable positioned within the first groove of the first portion is
greater than a radius of curvature of the optical fiber cable
positioned within the second groove; or a temperature decrease
which results in a greater contraction of the first composition of
the first portion than a contraction of the second composition of
the second portion resulting in the bending of the first portion,
the second portion and the optical fiber cable, wherein a radius of
curvature of the optical fiber cable positioned within the first
groove of the first portion is smaller than a radius of curvature
of the optical fiber cable positioned within the second groove.
11. The optical fiber cable assembly of claim 10, further including
an enclosure positioned about and restricting movement of the first
and second portions in a radial direction with respect to the
optical fiber cable, wherein the enclosure is constructed of a
third composition with a lower coefficient of thermal expansion
than the first coefficient of thermal expansion of the first
composition and the second coefficient of thermal expansion of the
second composition.
12. The optical fiber cable assembly of claim 1, wherein the
material comprises a ferromagnetic composition and the environment
change includes a change in an induced magnetic field.
13. The optical fiber cable assembly of claim 12, wherein the
material is constructed into a first portion secured to one side of
the optical fiber cable and a second portion secured to an opposing
second side of the optical fiber cable, further including: a first
solenoid positioned adjacent to and spaced apart from the first
portion; and a second solenoid positioned adjacent to and spaced
apart from the second portion.
14. The optical fiber cable assembly of claim 1, wherein the
material comprises a polymer which exhibits photoisomerization and
is secured to and is positioned at a predetermined location along
the length of the optical fiber cable, wherein the polymer is in
optical communication with a further included third core of the
optical fiber cable such that when a light beam from the third core
is received by the polymer transmits the force onto the optical
fiber cable changing a shape of the optical fiber cable.
15. The optical fiber cable assembly of claim 14, wherein the
composition of the polymer comprises an azobeneze or a derivative
of azobeneze.
16. The optical fiber cable assembly of claim 14, wherein a portion
of the cladding material is removed placing the third core in the
optical communication with the polymer.
17. The optical fiber cable assembly of claim 14, further includes
an enclosure positioned about the polymer and the optical fiber
cable radially confining at least a portion of the polymer against
the optical fiber cable.
18. An aircraft assembly, comprising: an aircraft; an optical fiber
cable positioned within the aircraft, wherein: the optical fiber
cable comprises at least a first core and a second core positioned
spaced apart from one another within a cladding material; the at
least first core and second core and the cladding material extend
in a direction of a length of the optical fiber cable; and material
secured to and positioned at a predetermined location along the
length of the optical fiber cable wherein the material comprises at
least one composition which when exposed to an environment change
the material transmits a force to the optical fiber cable changing
a shape of the optical fiber cable; or a polymer which exhibits
photoisomerization secured to and positioned at a predetermined
location along the length of the optical fiber cable, further
including a third core positioned within the cladding material in
photo communication with the polymer, wherein light transmitted
through the third core results in the polymer expanding and
transmitting a force to the optical fiber cable changing a shape of
the optical fiber cable.
19. The aircraft assembly of claim 18, wherein the material
comprises one of: polytetrafluoroethylene; a first composition
having a first coefficient of thermal expansion and a second
composition having a second coefficient of thermal expansion; or a
ferromagnetic composition.
20. The aircraft assembly of claim 18, wherein the polymer
comprises an azobeneze or a derivative of azobeneze.
Description
FIELD
[0001] This invention relates to an optical fiber cable, and more
particularly, to a multicore optical fiber cable.
BACKGROUND
[0002] An optical fiber cable is typically constructed of a glass
or plastic core. The core is generally configured in a cylindrical
shape and extends along the length of the cable. The core is
encased within a cladding material constructed of a glass material
which also extends along the length of the cable. The cladding
material is constructed of a glass or plastic material which is
different in composition from the material from which the core is
constructed. The cladding material will typically have a lower
refractive index than the refractive index of the material which is
used to construct the core. In various constructions of optical
fiber cable, the cladding material is surrounded by a buffer
material such as a protective coating or a protective encasement
constructed of high strength fibers. The optical fiber cable will
often also include an outer protective jacket constructed of a
strong durable material which surrounds the buffer material.
[0003] An optical fiber cable is used in different applications and
within different environments. The core will carry a transmitted
light beam which, in many examples, will carry data. The light beam
signal transmits data within the core at a high rate of speed and
the core provides a broader bandwidth than more traditional
metallic cable.
[0004] In some constructions of an optical fiber cable, multiple
cores are provided which are positioned within the cladding
material of the cable. These multicore optical cables are similarly
constructed as the single core optical fiber cable, however, the
multiple cores in the multicore optical fiber cable are positioned
within the cladding material spaced apart from one another at known
distances. In a normal operating condition with the cable extending
in a relatively straight orientation which may include relatively
gentle curvatures, the cores are isolated from one another from
cross communication between cores.
[0005] The transmission of a light beam in a first core of the
multiple cores, generates an evanescent field that extends beyond
the boundary surface of the first core. The evanescent field
extends into the lower refractive indexed cladding material. With a
second core present having a higher refractive index than that of
the cladding material and with the second core positioned in close
enough proximity to the first core, a phenomenon of evanescent
coupling takes place between the first and second cores. As
mentioned above, the separation between cores within a multiple
core optical fiber cable will typically position, for example, a
first and second core sufficiently far enough apart such that a
signal transmitted within the first core will not affect the second
core. However with a first and second core moved to a position such
that they are in close enough proximity to one another, the
evanescent field created by the transmission within the first core
will affect and influence the second core. Bending of a core
carrying a signal also causes the shape of the evanescent field to
change shape. If the core is bent past a critical point the field
may interact with an adjacent core. These affects are commonly
known as an evanescent coupling phenomenon which results in a
transfer of energy to the second core.
[0006] Should the second core not be transmitting a signal at the
time the evanescent field becomes present, the evanescent coupling
will propagate a signal in the second core. This propagated signal
in the second core can be detected and measured. Should the second
core already be transmitting a signal at the time of the evanescent
coupling, the evanescent coupling will alter that signal within
that second core. The altered signal in the second core can also be
detected and measured.
[0007] When a light beam is transmitted in a first core of a
multiple core optical fiber cable, where the cable is positioned to
extend in a relatively straight orientation or with gentle curves,
the light beam internally reflects at the boundary of the first
core as the light beam is transmitted along the core without cross
communication occurring between cores in the multicore optical
fiber cable. However, should the multicore optical fiber cable be
positioned with a sufficient bend in the cable, the angle of
incident of the light beam on the boundary of the first core
carrying a light beam transmission will change as a result of the
bend in that core in which the light beam is transmitted. Should
the angle of incident of the light beam transmission exceed a
critical angle for the material from which the first core is
constructed, at least a portion of the light beam will be refracted
and be transmitted into the cladding material. This transmission of
the light beam signal can interact with a nearby second core and
result in the refracted light beam being transmitted along a second
core. The transmission of this transmitted light beam within the
second core can also be detected and measured.
[0008] With a light beam signal being transmitted in a first core,
the transfer of energy to a second core can be facilitated through
the operation of the evanescent coupling and/or by way of the light
refraction phenomena. Thus, with moving a first and a second core
within a distance of the field of influence of the evanescent field
and changing the distance between the first and second core within
the field of influence will result in changing the amount of energy
being transferred to the second core. As the first and second core
move closer together the transfer of energy will be greater to the
second core and as the distance of separation increases the amount
of energy transferred to the second core is diminished. In the
instance of bending of the cable, this results in the bending of
the boundary of the first core. Once the internally reflected light
beam within the first core exceeds beyond the critical angle of the
first core, the amount of energy refracted to and transmitted to
the second core increases and correspondingly the amount of energy
transmitted decreases as the bend returns the angle of incident of
the light beam closer to the critical angle. Thus, with a change of
the optical fiber cable configuration along with a transmission of
a light beam along a first core, a detectable and measurable energy
transfer into the second core as a result of one or both of the
phenomena will take place.
[0009] With the cores within a multicore optical cable being
constructed of a material such as glass, the glass is a
substantially inert material, having low thermal expansion
coefficients and is resistant to compressive strain. Thus, in order
to carry out induced evanescent coupling and/or transmission of
light beam energy from a first to a second core within a multicore
optical fiber cable, localized alteration of the shape of the cable
needs to take place which can effect distance between the first and
second cores within the optical fiber cable and/or localized
alteration of the shape of the cable with bending of the optical
fiber cable which results in bending of the cores within the cable
needs to be accomplished. This localized manipulation of the
optical fiber cable needs to be usable and flight worthy reliable.
Such manipulation can result in the use of multicore optical fiber
cable, with appropriate calibration as needed, as a sensor, switch
or modulator.
[0010] The features, functions, and advantages that have been
discussed can be achieved independently in various embodiments or
may be combined in yet other embodiments further details of which
can be seen with reference to the following description and
drawings.
SUMMARY
[0011] An embodiment provides an optical fiber cable assembly which
includes an optical fiber cable which includes at least a first
core and a second core positioned spaced apart from one another
within a cladding material, wherein the at least first core and the
second core and the cladding material extend in a direction of a
length of the optical fiber cable. The assembly further includes
material positioned at a predetermined location along the length of
the optical fiber cable wherein the material is associated with the
optical fiber cable such that when the material is exposed to an
environment change the material transmits a force onto the optical
fiber cable changing a shape of the optical fiber cable.
[0012] An embodiment provides an aircraft assembly which includes
an aircraft and an optical fiber cable positioned within the
aircraft, wherein the optical fiber cable includes at least a first
core and a second core positioned spaced apart from one another
within a cladding material and the at least first core and second
core and the cladding material extend in a direction of a length of
the optical fiber cable. The assembly further includes a material
secured to and positioned at a predetermined location along the
length of the optical fiber cable wherein the material comprises at
least one composition which when exposed to an environment change
the material transmits a force to the optical fiber cable changing
a shape of the optical fiber cable; or a polymer which exhibits
photoisomerization secured to and positioned at a predetermined
location along the length of the optical fiber cable further
including a third core positioned within the cladding in photo
communication with the polymer, wherein light transmitted through
the third core results in the polymer expanding and transmitting a
force to the optical fiber cable changing a shape of the optical
fiber cable.
BRIEF SUMMARY OF THE DRAWINGS
[0013] FIG. 1 is schematic perspective view of a multicore optical
fiber cable;
[0014] FIG. 2 is a cross section view of the multicore optical
fiber cable as seen across line 2-2 in FIG. 1;
[0015] FIG. 3 is a schematic side elevation view of an optical
fiber cable assembly which includes the multicore optical fiber
cable of FIG. 1;
[0016] FIG. 4 is a schematic exploded view of a first embodiment of
the optical fiber cable assembly of FIG. 3;
[0017] FIG. 5A is a cross section view along line 5-5 of FIG. 4 of
the first embodiment of the optical fiber cable assembly of FIG. 4
assembled;
[0018] FIG. 5B is a cross section view of another example of the
first embodiment of the optical fiber cable assembly of FIG.
5A;
[0019] FIG. 6 is a schematic view of the optical fiber cable of the
first embodiment wherein an increase in temperature was exposed to
the first embodiment of the optical fiber cable assembly of FIG. 4
changing the shape of the optical fiber cable with stretching the
optical fiber cable;
[0020] FIG. 7 is a schematic view of the optical fiber cable of the
first embodiment wherein a decrease in temperature was exposed to
the first embodiment of the optical fiber cable assembly of FIG. 4
changing the shape of the optical fiber cable with contracting the
optical fiber cable;
[0021] FIG. 8 is a schematic exploded view of a second embodiment
of the optical fiber cable assembly of FIG. 3;
[0022] FIG. 9A is a cross section view along line 9-9 of FIG. 8 of
the second embodiment of the optical fiber cable assembly of FIG. 8
assembled;
[0023] FIG. 9B is a cross section view of another example of the
second embodiment of the optical fiber cable assembly of FIG.
9A;
[0024] FIG. 10 is a side elevation view of the second embodiment of
the optical fiber cable assembly of FIG. 8 wherein an increase in
temperature has been exposed to the optical fiber cable assembly
changing the shape of the optical fiber cable with bending the
optical fiber cable;
[0025] FIG. 11 is a side elevation view of the second embodiment of
the optical fiber cable assembly of FIG. 8 wherein a decrease in
temperature has been exposed to the optical fiber cable assembly
changing the shape of the optical fiber cable with bending the
optical fiber cable;
[0026] FIG. 12 is another example of a schematic cross section view
of the second embodiment of the optical fiber cable assembly as
shown in FIG. 9B;
[0027] FIG. 13 is a schematic cross section of a third embodiment
of the optical fiber cable assembly of FIG. 3 with a ferromagnetic
composition associated with the optical fiber cable in the presence
of solenoids;
[0028] FIG. 14 is a schematic side elevation cross section view of
a fourth embodiment of the optical fiber cable assembly;
[0029] FIG. 15 is a schematic cross section view as seen along line
15-15 of FIG. 14; and
[0030] FIG. 16 is a perspective view of an aircraft assembly.
DESCRIPTION
[0031] Multicore optical fiber cable provides high rate of
transmission and high bandwidth for each core. The cores are
sufficiently spaced apart so as not to cause cross communications
between cores with the cable extending in a relatively straight
configuration inclusive of gentle curves.
[0032] One way cross communication can occur between cores is by
way of bending of the cable which results in bending of the cores.
Sufficient bending of the cores can cause a light beam traveling
within a first core to increase its angle of incident with the
boundary of the first core beyond the critical angle for that
material. This bending of the boundary of the first core will
result in the light beam to refract out of the first core. The
refracted light beam is transmitted to a second core within the
cable. This refracted light beam will transmit along the second
core. This phenomenon can be detected in the second core and be
measured.
[0033] Another way cross communication can take place is by way of
a phenomenon known as evanescent coupling between a first core and
a second core. A light signal transmitting within a first core
generates an evanescent field as earlier discussed. The field
extends beyond the boundary of the first core and into the
surrounding cladding material. With altering the distance between a
first core and a second core, the second core moves closer to the
first core and within the influence of the evanescent field. With
altering the bend radius of the core, the shape of the evanescent
field changes as well. As a result, an evanescent coupling of the
first and second cores takes place. The evanescent coupling, with
the second core not already carrying a signal, will result in the
propagation of a new signal within the second core. Should the
second core already be transmitting a signal at the time of the
coupling, the signal being transmitted within the second core will
be altered by the evanescent coupling. The closer the positioning
of the first and second cores will provide a stronger influence by
the evanescent field on the second core and as the first and second
cores are separated apart the influence diminishes. As earlier
discussed, this phenomenon of evanescent coupling can be detected
from the second core and can also be measured.
[0034] Thus, with a first core within a multicore optical fiber
cable transmitting a light beam, the changing of the shape or
configuration of the multicore optical fiber cable such as by
bending the cores affecting transmission of energy from the first
core to a second core and/or moving the first and second cores
within a field of evanescent coupling, a detectable and measurable
energy influence within the second core takes place. This
detectable and measurable occurrence facilitates, with appropriate
calibration as needed, the multicore optical fiber cable to operate
as a useful sensor, switch or modulator.
[0035] As a result, there is a need to be able to provide usable
and reliable capability of changing the configuration or shape of
multicore optical fiber cable at predetermined locations along the
cable that can affect the bending of the cores and/or proximity of
the cores within the cable. In referring to FIGS. 1 and 2, a
multicore optical cable 10 is shown. In this example, multicore
optical cable 10 includes a centrally positioned center core 12 and
six concentrically distributed cores 14 positioned around center
core 12. Any number of cores can be employed for multicore optical
cable 10 so long as there are a minimum of at least two cores are
present and are used in interacting with one another with respect
to transfer of energy from one core to another core as will be
appreciated in the discussions of various embodiments herein. As
mentioned earlier, cores 12, 14 are constructed from one of a
variety of materials such as glass or plastic. The diameter of the
cores can vary and in this example the diameter of each of cores
12, 14 are eight microns (8 .mu.m). Cores 12, 14 are cylindrical in
shape and extend along length L of cable 10 spaced apart from one
another within cladding material 16. As mentioned earlier, the
spacing between cores 12, 14 are at a sufficient distance from one
another so as to avoid cross communication between cores 12,
14.
[0036] Cladding material 16 is, in this example, constructed of a
glass material. Cladding material 16 is constructed of a material
having a lower refractive index than the refractive index of
material of cores 12, 14. Cladding material 16 also extends along
length L of cable 10. In an example of a traditional operation of
multicore fiber cable 10, a light beam carrying data is transmitted
in a first core such as 12, cable 10 is positioned to extend so as
to maintain light beams carrying data reflecting internally with
boundary 18. This would have the orientation of cable 10 extending
such that the angle of incidence of the transmitting light beam is
kept at less than a critical angle for the material the core is
constructed. This will reduce or eliminate the light beam from
refracting into cladding material 16.
[0037] Additional protective layers are applied to the exterior of
cladding material 16 to provide protection to the cores 12, 14 from
undesirable conditions such as moisture and impact forces exerted
onto cable 10. Buffer material 20 is constructed from one of a
variety of constructions such as a polymer such as polyimide, dual
acrylate, etc. Additional coverings and jackets can also be further
applied to buffer material 20 to provide to provide further
protection to cores 12, 14.
[0038] In referring to FIG. 3, a schematic representation of a
multicore optical fiber cable assembly 22 of the present disclosure
is shown. Various embodiments of optical fiber cable assembly 22
will be discussed herein which include use of material 24
positioned at a predetermined location 26 along length L of optical
fiber cable 10, wherein material 24 is associated with optical
fiber cable 10 such that when material 24 is exposed to an
environment change, material 24 transmits a force onto optical
fiber cable 10, changing a shape of optical fiber cable 10. As will
be discussed herein, various examples of composition(s) of material
24 and their structure(s) will be shown, as well as, various kinds
of environment change to which material 24 will be exposed will
also be discussed. In addition, various changes as to shape of
optical fiber cable 10 will be discussed that will facilitate the
communication or transfer of energy from a first core to a second
core of optical fiber cable 10.
[0039] A first embodiment 28 of optical fiber cable assembly 22 is
shown in FIGS. 4-7. Optical fiber cable 10, in this example, has
first core 30 and second core 32 positioned spaced apart from one
another within cladding material 16. First and second cores 30, 32
and cladding material 16 extend along a direction of length L of
optical fiber cable 10. In this example of first embodiment 28,
material 24 is positioned at a predetermined location 26 along
optical fiber cable 10 and is structured to have a first portion 36
with first side 38 which defines first groove 40 with first groove
40 having first surface 42. Material 24 is further structured to
have second portion 44 with first side 46 which defines a second
groove 48 with second groove 48 having second surface 50. As seen
in FIG. 5A, for example, optical fiber cable 10 is positioned
within the first and second grooves 40, 48 with first side 38 of
the first portion 36 and first side 46 of second portion 44
positioned in a facing relationship to one another.
[0040] In first embodiment 28, material 24 is secured to fiber
optical cable 10. First side 38 of first portion 36 and first side
46 of second portion 44 are bonded together with an adhesive such
as an epoxy or other thermoset material. First and second portions
36, 44 are bonded together with optical fiber cable 10 positioned
within first groove 40 and bonded to first surface 42 of first
groove 40 and optical fiber cable 10 positioned within second
groove 48 bonded to second surface 50 of second groove 48. Bonding
of optical fiber cable 10 within first and second grooves 40, 48
utilizes an adhesive such as an epoxy or other thermoset material.
An outer surface 52 of optical fiber cable 10 is bonded to first
surface 42 of first groove 40 and bonded to second surface 50 of
second groove 48. In one example outer surface 52 includes outer
surface of cladding material 16 of optical fiber cable 10. In
another example, outer surface 52 includes outer surface of buffer
material 20 (not shown in FIGS. 4-5B) surrounding cladding material
16 of optical fiber cable 10.
[0041] One example of a structure of material 24 of first
embodiment 28 is shown in FIG. 5A. The external shape of material
24, in this example, is configured in more of a square or
rectangular configuration. In contrast, in a second example of a
structure of material 24 is shown in FIG. 5B. The external shape of
first portion 36' and second portion 44' are configured to have a
more rounded external shape and a cylindrical configuration along
the length L of cable 10. Variations of external shapes of material
24 may be employed depending on the space available in which
assembly 22 will need to operate.
[0042] In first embodiment 28, material 24 employed is constructed
of the same composition which, in this example, includes
polytetrafluoroethylene. Polytetrafluoroethylene is useful for
operating in various temperature ranges inclusive of cryogenic
temperature ranges and in this example is useful in facilitating
optical fiber cable assembly 22 to operate as a sensor where the
environment change includes a temperature change. For example, as
an environment temperature increases material 24,
polytetrafluoroethylene, (not shown in FIG. 6), will expand and
with material 24 bonded to optical fiber cable 10, material 24
exerts a force onto optical fiber cable 10. In this instance, the
force results in stretching of optical fiber cable 10 at the
predetermined location 26, as seen in FIG. 6. Stretching of cable
10 results in a reduction in diameter of optical fiber cable 10 as
seen as D1 in predetermined location 26 of optical fiber cable 10.
In contrast, as seen in FIG. 7, with a decrease in temperature,
material 24, polytetrafluoroethylene, (not shown in FIG. 7),
contracts which results in a contracting force being exerted onto
optical fiber cable 10 at predetermined location 26 resulting in an
increase in diameter D2 of optical fiber cable 10 at predetermined
location 26.
[0043] In this first embodiment 28, the decreasing of the diameter
of optical fiber cable 10, as seen in FIG. 6, will result in first
core 30 and second core 32 moving closer together with respect to
one another. With first and second cores 30, 32 moving closer
together an evanescent coupling phenomenon is provided an
opportunity to take place between first and second cores 30, 32.
For example, with first core 30 carrying a light beam transmission
and second core 32 not carrying a light beam, as the temperature
increases material 24 stretches and first and second cores 30, 32
move closer together and second core 32 moves into a field of
influence of the evanescent field generated by the transmission
within first core 30. The closer second core 32 comes with respect
to first core 30, a stronger evanescent coupling occurs between
first and second cores 30, 32 resulting in a stronger propagation
of a transmission within second core 32. With a reduction in
temperature, material 24 contracts thereby contracting cable 10
with diameter D2 increasing. First and second cores 30, 32 move
apart from one another. With diameter D2 increasing, the evanescent
coupling weakens and so does the propagation of a transmission in
second core 32.
[0044] As the temperature changes in the environment, the
corresponding stretching and contracting of optical fiber cable 10
will take place. The evanescent coupling will provide a detectable
and measurable propagation of a transmission in second core 32 or
in an alternative where second core 32 is already carrying a
transmission, the coupling will cause an alteration of an existing
transmission within second core 32. Associated calibration of the
evanescent coupling phenomenon, in either instance where second
core 32 is not already transmitting a signal or is already
transmitting a signal, provides assembly 22 to operate as a
temperature sensor.
[0045] In referring to FIGS. 8-12 a second embodiment 54 of optical
fiber cable assembly 22 is shown. Optical fiber cable 10, in this
example, similarly as described above for first embodiment 28, has
first core 30 and second core 32 positioned spaced apart from one
another within cladding material 16. First and second cores 30, 32
and cladding material 16 extend along a direction of length L of
optical fiber cable 10.
[0046] In this example of second embodiment 54, material 24 is
positioned at a predetermined location 26 along optical fiber cable
10 and material 24 is constructed of two compositions wherein a
first composition 56 is structured to have a first coefficient of
thermal expansion and a second composition 58 having a second
coefficient of thermal expansion. The first composition 56 and the
second composition 58 are bonded together, which will be discussed
below, similar to the structure described for the first embodiment
28. An adhesive such as an epoxy or other thermoset material is
used in bonding the first composition 56 and second composition 58
to optical fiber cable 10 as well as to each other.
[0047] First composition 56 is constructed of first portion 60, as
seen in FIG. 8. First portion 60 has a first side 62 which defines
first groove 64 wherein first groove 64 has a first surface 66.
Second composition 58 is constructed into a second portion 68 with
a first side 70 which defines a second groove 72 wherein the second
groove 72 has a second surface 74. Optical fiber cable 10 is
positioned within the first and second grooves 64, 72 with first
side 62 of first portion 60 and with first side 70 of second
portion 68 positioned in a facing relationship to one another.
First side 62 of first portion 60 and first side 70 of second
portion 68 are bonded together with an adhesive such as an epoxy or
other thermoset material and optical fiber cable 10 is bonded to
first surface 66 of first groove 64 and to second surface 74 of
second groove 72 with adhesive such as an epoxy or other thermoset
material. This securement of material 24 to cable 10 provides
material 24 the ability to exert a force onto cable 10. Outer
surface 76 of cable 10 is bonded to first surface 66 of first
groove 64 and bonded to second surface 74 of second groove 72 which
in one example includes outer surface 76 to include cladding
material 16 of optical fiber cable 10 or in another example to
include buffer material 20 surrounding cladding material 16 of
optical fiber cable 10.
[0048] One example of the structure of material 24 of second
embodiment 54 is shown in FIG. 9A, wherein the external shape is
configured in more of a square or rectangular configuration. In
contrast, in a second example of a structure of material 24 in this
second embodiment 54 is shown in FIG. 9B. The external shape of
first portion 60' and second portion 68', as shown in FIG. 9B, are
configured to have a more rounded external shape and a cylindrical
configuration along the length L of cable 10. Variations of
external shapes of material 24 may be employed depending on the
space available in which assembly 22 will need to operate.
[0049] In this example of the second embodiment 54, the first
coefficient of thermal expansion of first composition 56 is greater
than the second coefficient of thermal expansion coefficient of
second composition 58. Thus, first composition 56 will experience a
greater expansion than second composition 58 as temperature
increases and first composition 56 will experience a greater
contraction than second composition 58 as the temperature
decreases. The first and second compositions 56, 58 can be of a
wide variety of compositions such as metal, composite, polymers,
etc. so long as the compositions for the first portion 60 and the
second portion 68 for second embodiment 54 have different
coefficients of thermal expansion. With first and second portions
60, 68 bonded to cable 10, each will expand or contract at
different rates as the temperature changes. This will cause cable
10 to change shape with experience predominantly bending with
experiencing some either stretching or contracting of cable 10
diameter.
[0050] In referring to FIGS. 10 and 11, an environment change of
temperature is exposed to material 24 of second embodiment 54 of
optical fiber cable assembly 22, wherein material 24 includes first
portion 60 constructed of a first composition 56 and a second
portion 68 constructed of a second composition 58. In referring to
FIG. 10, assembly 22 is exposed to a temperature increase. As
mentioned above, first portion 60 is constructed of first
composition 56 having a higher thermal coefficient of expansion
than second composition 58 from which second portion 68 is
constructed. As a result, first composition 56 of first portion 60
expands more than second composition 58 of second portion 68. Some
stretching takes place with respect to cable 10 however, bending of
cable 10 is of a greater consequence such that first portion 60,
second portion 68 and optical fiber cable 10 all bend. Bending of
cable 10 is seen with a radius of curvature R of the optical fiber
cable positioned within the first groove 64 of first portion 60 and
is greater than a radius of curvature R1 of the optical fiber cable
positioned within second groove 72.
[0051] In referring to FIG. 11, assembly 22 is exposed to a
temperature decrease. First portion 60 is constructed of first
composition 56 having a higher coefficient of thermal expansion
than second composition 58 from which second portion 68 is
constructed. As a result, first composition 56 of first portion 60
results in a greater contraction than second composition 58 of
second portion 68. Some contraction of cable 10 takes place,
however, bending of cable 10 is of greater consequence such that
first portion 60, second portion 68 and optical fiber cable 10 all
bend. Bending of cable 10 is seen with a radius of curvature R1 of
optical fiber cable 10 positioned within second groove 72 of second
portion 68 and is greater than a radius of curvature R of the
optical fiber cable 10 positioned within first groove 64 of first
portion 60.
[0052] The effect to cable 10 utilizing the second embodiment 54 of
the optical fiber cable assembly 22 provides some stretching and
contracting of cable 10 in response to the temperature change,
however, the substantial change in shape of cable 10 is a result of
cable 10 bending. As discussed earlier, as cores such as first core
30 bends beyond a critical angle, of the material which first core
30 is constructed, the light beam transmitted within first core 30
begins to refract out of and beyond boundary 18 of the core. The
transmission of light from first core 30 increases as the angle of
incident of the transmitted light beam goes further beyond the
critical angle for that material. Thus, increased bending will
result in more light being transmitted beyond boundary 18 of first
core 30 and is available to be received by second core 32 and
transmitted along second core 32. Thus, increased bending will
result in a stronger transmission in second core 32 and increased
evanescent coupling. Less bending will result in less light
transmission into and along the second core 32 and decreased
evanescent coupling. However, the calibration of the effect of
transmission of a signal within the second core 32 will provide
second embodiment 54 of optical fiber cable assembly 22 to operate
as a temperature sensor.
[0053] In referring to FIG. 12, second embodiment 54 of optical
fiber cable assembly 22 further includes an enclosure 78, such as
constructed in a configuration as a ring or cylinder. Enclosure 78
is positioned about and restricts movement of the first and second
portions 60, 68 in a radial direction with respect to optical fiber
cable 10. Enclosure 78 is constructed of a third composition 80
having a lower coefficient of thermal expansion than the first
coefficient of thermal expansion of first composition 56 and second
coefficient of thermal expansion of second composition 58.
Enclosure 78 provides confinement of first and second portions 60,
68 thereby providing a more accentuated effect the expansion and
contraction of first portion 60 and second portion 68 will have on
cable 10. As a result, the application of enclosure 78 will provide
increased sensitivity in optical fiber cable assembly 22 operating
as a temperature sensor.
[0054] In referring to FIG. 13, a third embodiment 82 of optical
fiber cable assembly 22 is shown. Material 24 in this embodiment
includes a ferromagnetic composition 84 and the environment change
includes a change in an induced magnetic field. A first portion 86
of ferromagnetic composition 84 is secured to one side 88 of
optical fiber cable 10 and second portion 90 of ferromagnetic
composition 84 is secured to an opposing side 92 of optical fiber
cable 10. Ferromagnetic composition 84 is secured to cable 10 with
an adhesive such as an epoxy or other thermoset material, or
directly deposited to cable 10.
[0055] A first solenoid 94 is positioned adjacent to and spaced
apart from first portion 86 and second solenoid 96 is positioned
adjacent to and space apart from second portion 90. Brackets 98 are
provided to maintain cable 10 confined within alignment with first
and second solenoids 94, 96. Activating for example only first
solenoid 94 will attract first portion 86 toward first solenoid 94
bending cable 10. Similarly only activating second solenoid 96 will
attract second portion 90 toward second solenoid 96 bending cable
10. This third embodiment 82 can be used to transmit light from
first core 30 for example into a second core 32 wherein light beam
transmitted along first core 30 can refract out of first core 30
with bending causing the angle of incident of the light beam
exceeding the critical angle for the material of first core 30, and
causing an increase in evanescent coupling. The light that
transmits out of first core 30 is received by second core 32 and
transmits along second core 32 wherein that transmission along
second core 32 can perform as a switch or with a signal already
transmitting within second core 32 operate as a modulator.
[0056] In referring to FIGS. 14 and 15, a fourth embodiment 100 of
the optical fiber cable assembly 22 is shown. A first core 30 and a
second core 32 are shown. Material 24 includes polymer 102 which
exhibits photoisomerization. With polymer 102 exposed to a light
beam, polymer 102 expands and with removal of the light beam the
polymer 102 material returns to its original position. Polymer 102
is directly adhered to cable 10 or secured to cable 10 with an
adhesive such as an epoxy or other thermoset material and is
positioned at a predetermined location 26 along length L of optical
fiber cable 10. Polymer 102 is in optical connection with third
core 104 of optical fiber cable 10. With this arrangement, a light
beam transmitted along third core 104 is received by polymer 102
and polymer 102 transmits a force onto optical fiber cable 10
changing the shape of optical fiber cable 10 with bending cable 10.
As a result, for example, with first core 30 carrying a light beam,
the bending of cable 10 causes first core 30 to bend changing the
angle of incident of the transmitted light beam and causing an
increase in evanescent coupling. With the light beam exceeding the
critical angle for first core 30 light will refract out of first
core 30 and into second core 32. This provides fourth embodiment
100 to operate, with calibration as needed, as a switch or even a
modulator.
[0057] Polymer 102 can include an azobeneze, derivative of
azobeneze or other polymer which exhibits photoisomerization. In
this example, a portion of cladding material 16 is removed from
cable 10 placing third core 104 in photo communication with polymer
102. In another example of fourth embodiment 100, enclosure 106 is
positioned about polymer 102. Radially confining at least a portion
of the polymer 102 against optical fiber cable 10. Enclosure 106
shields polymer 102 from ambient light and also enhances the
sensitivity of assembly 22 with confining the expansion of polymer
102 and directing the exertion of that force onto cable 10.
[0058] In referring to FIG. 16, aircraft assembly 108 is shown
which includes aircraft 110. Assembly 108 includes optical fiber
cable 10 positioned within aircraft 110. Optical fiber cable 10
includes at least a first core 30 and a second core 32 positioned
spaced apart from one another within a cladding material 16, as
seen in FIGS. 1 and 2. The first and second cores 30, 32 extend in
a direction L of the length of optical fiber cable 10. Material 24,
as seen in FIG. 3, is secured to and positioned at a predetermined
location 26 along length L of the optical fiber cable 10. Material
24 includes at least one composition which when exposed to an
environment change the material transmits a force to optical fiber
cable 10 changing a shape of optical fiber cable 10, as seen in
FIGS. 4-13. Material 24 includes one of polytetrafluoroethylene; a
first composition having a first coefficient of thermal expansion
and a second composition having a second coefficient of thermal
expansion; or a ferromagnetic composition.
[0059] Alternatively, material 24 includes polymer 102 which
exhibits photoisomerization secured to and positioned at a
predetermined location 26 along length L of optical fiber cable 10,
as seen in FIGS. 14 and 15, which further includes third core 104
positioned within cladding material 16 in photo communication with
polymer 102. Light transmitted through third core 104 results in
polymer 102 expanding and transmitting a force to optical fiber
cable 10 changing a shape of optical fiber cable 10. Polymer 102
includes an azobeneze or a derivative of azobeneze.
[0060] As described above, these materials can be employed to
facilitate exertion of a force onto cable 10 resulting in changing
the shape of cable 10. With changing the shape of cable 10, as
described earlier, an imparting one or both phenomena of,
evanescent coupling of first and second cores 30, 32 and/or light
beam transmission from first core 30 into second core 32 can take
place providing optical fiber cable assembly 22 to operate as a
sensor, switch or modulator.
[0061] While various embodiments have been described above, this
disclosure is not intended to be limited thereto. Variations can be
made to the disclosed embodiments that are still within the scope
of the appended claims.
* * * * *