U.S. patent application number 09/772849 was filed with the patent office on 2001-07-05 for fiber-optic free-space micromachined matrix switches.
This patent application is currently assigned to AT&T Corp. Invention is credited to Lin, Lih-Yuan.
Application Number | 20010006569 09/772849 |
Document ID | / |
Family ID | 26669344 |
Filed Date | 2001-07-05 |
United States Patent
Application |
20010006569 |
Kind Code |
A1 |
Lin, Lih-Yuan |
July 5, 2001 |
Fiber-optic free-space micromachined matrix switches
Abstract
An optical switch device redirects a beam of light traveling
along a first direction to a second direction and includes a base
member, a reflective panel and an actuator. The reflective panel is
pivotally connected to the base member and moves between a
reflective state and a non-reflective state. In the reflective
state, the reflective panel is disposed to redirect the beam of
light from the first direction to the second direction. In the
non-reflective state, the reflective panel is disposed to permit
the light beam to travel along the first direction. The actuator is
connected to the base member and the reflective panel and is
operative to cause the reflective panel to move to and between the
reflective state and the non-reflective state. An array of optical
switch devices can be arranged to form a free-space optical matrix
crossconnect apparatus.
Inventors: |
Lin, Lih-Yuan; (Middletown,
NJ) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. Box 19928
Alexandria
VA
22320
US
|
Assignee: |
AT&T Corp
|
Family ID: |
26669344 |
Appl. No.: |
09/772849 |
Filed: |
January 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09772849 |
Jan 31, 2001 |
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09377694 |
Aug 20, 1999 |
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6215921 |
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60058222 |
Sep 9, 1997 |
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Current U.S.
Class: |
385/18 ;
385/17 |
Current CPC
Class: |
G02B 6/3512 20130101;
G02B 6/356 20130101; H04Q 11/0005 20130101; G02B 6/3546 20130101;
G02B 6/357 20130101; G02B 6/3564 20130101; G02B 6/122 20130101;
G02B 6/3574 20130101; H04Q 2011/003 20130101; G02B 6/3594 20130101;
G02B 2006/12104 20130101 |
Class at
Publication: |
385/18 ;
385/17 |
International
Class: |
G02B 006/35 |
Claims
What is claimed is:
1. An optical switch device for redirecting at least a portion of a
beam of light traveling in free space along a first direction to a
second direction different from the first direction, comprising: a
base member; a reflective panel pivotally connected to the base
member and unbiasedly movable between a reflective state wherein
the reflective panel is disposed to redirect the beam of light from
the first direction to the second direction and a non-reflective
state wherein the reflective panel is disposed to permit the beam
of light to travel along the first direction; and an actuator
connected to the base member and the reflective panel and operative
to cause the reflective panel to move to and between the reflective
state and the non-reflective state.
2. An optical switch device according to claim 1, wherein the
reflective panel includes a first surface and a second surface
disposed opposite the first surface, the first surface being
reflective.
3. An optical switch device according to claim 2, wherein the
second surface is reflective.
4. An optical switch device according to claim 1, wherein the
reflective panel is fabricated from a material being partially
reflective and partially transparent whereby, when the reflective
panel is disposed in the reflective state, a portion of the beam of
light is redirected to the second direction while a remaining
portion of the beam of light continues in the first direction.
5. An optical switch device according to claim 1, wherein the
reflective panel includes at least one hinge pin member and at
least one hinge pin connecting member disposed apart from one
another and connected to an edge portion of the reflective panel,
the at least one hinge pin connecting member projecting outwardly
from the edge portion of the reflective panel for mounting the at
least one hinge pin member between the at least one hinge pin
connecting member.
6. An optical switch device according to claim 5, further
comprising a staple element having a channel sized to receive the
at least one hinge pin member, the staple element connected to the
base member with the at least one hinge pin member disposed within
the channel to provide pivotal movement of the reflective panel
about a pivot axis extending through the at least one hinge pin
member.
7. An optical switch device according to claim 6, wherein the
staple element and the at least one hinge pin member are disposed
in close proximity to each another in a manner to permit the
reflective panel to freely pivot about the pivot axis without
interference from the staple element.
8. An optical switch device according to claim 1; wherein the
actuator includes a hinge assembly and a translation plate, the
hinge assembly having at least one connecting rod with a first end
of the connecting rod pivotally connected to the reflective panel
and an opposite second end pivotally connected to the translation
plate, the translation plate slidably connected to the base member
and movable between a first position wherein the reflective panel
is in the reflective state and a second position wherein the
reflective panel in the non-reflective state.
9. An optical switch device according to claim 8, wherein the
actuator includes one of a scratch drive actuator mechanism and a
comb drive mechanism, a respective one of the scratch drive
actuator mechanism and the comb drive mechanism being connected to
the translation plate and operative in conjunction with the base
member to cause the translation plate to move to at least the first
position.
10. An optical switch device according to claim 9, wherein the
respective one of the scratch drive actuator mechanism and the comb
drive mechanism causes the translation plate to move to the second
position.
11. An optical switch device according to claim 9, wherein the
actuator includes a spring element connected to and between the
base member and the translation plate and operative to cause the
translation plate to move from the first position to the second
position.
12. An optical switch device according to claim 8, wherein the
translation plate includes at least a first channel and a second
channel and wherein the actuator includes a first driving pin and a
second driving pin, the first driving pin sized for slidable
engagement with the first channel and the second driving pin sized
for slidable engagement with the second channel whereby the first
driving pin slidably engages the first channel while the second
driving pin retracts from the second channel so that the
translation plate moves to the first position with the second
driving pin being positioned offset relative to the second channel
and the second driving pin slidably engages the second channel
while the first driving pin retracts from the first channel so that
the translation plate moves to the second position with the first
driving pin being positioned offset relative to the first
channel.
13. An optical switch device for reflecting at least one beam of
light, comprising: a base member; reflective means connected to the
base member and unbiasedly movable between a reflective state for
reflecting the at least one beam of light and a non-reflective
state; and actuator means operative with the base member and the
reflective means for causing the reflective means to move to and
between the reflective state and the non-reflective state.
14. An optical switch device according to claim 13, wherein the
reflective means includes a reflective panel having a first surface
and a second surface disposed opposite the first surface, the first
surface being reflective.
15. An optical switch device according to claim 14, wherein the
second surface is reflective so that a second beam of light can be
reflected while the first surface reflects the at least one beam of
light.
16. An optical switch device according to claim 13, wherein the
reflective means includes a reflective panel fabricated from a
material being partially reflective and partially transparent
whereby, when the reflective panel is disposed in the reflective
state, a portion of the at least one beam of light is redirected to
the second direction while a remaining portion of the at least one
beam of light continues in the first direction.
17. An optical switch device according to claim 14, wherein the
actuator means includes one of a scratch drive actuator mechanism
and a comb drive mechanism.
18. A free-space optical matrix crossconnect apparatus, comprising:
a base member; an array of reflective elements operatively
connected to the base member and arranged in a plurality of columns
and rows, each reflective element including a reflective panel and
an actuator, the reflective panel being pivotally connected to the
base member and unbiasedly movable between a reflective state
wherein the reflective panel is disposed perpendicularly relative
to the base member and a non-reflective state wherein the
reflective panel is disposed in a facially opposing relationship on
the base member; a plurality of fiber optic ports, each fiber optic
port disposed along a periphery of the base member at a respective
one of the columns and rows and capable of emitting and receiving a
light beam so that when the light beam from a light emitting fiber
optic port located at a selected one of the columns and rows is
transmitted to a selected light receiving fiber optic port located
at a selected remaining one of the rows and columns, the optical
switch device located at an intersection formed by the selected
column and row is actuated by the actuator to move the reflective
panel from the non-reflective state to the reflective state to
reflect the light beam from the light emitting fiber optic port to
the selected light receiving fiber optic port.
19. A free-space optical matrix crossconnect apparatus according to
claim 18, further comprising a plurality of collimator elements,
each collimator element being disposed adjacent to respective ones
of each fiber optic port and between each fiber optic port and the
reflective elements.
20. A free-space optical matrix crossconnect apparatus according to
claim 19, wherein the plurality of collimator elements and the
plurality of fiber optic ports are connected to the base
member.
21. A free-space optical matrix crossconnect apparatus according to
claim 18, wherein when the reflective element located at the
intersection formed by the selected column and row is in the
reflective state, remaining ones of the reflective elements located
in the selected column and row are in the non-reflective state.
22. A free-space optical matrix crossconnect apparatus according to
claim 21, wherein a plurality of light beams from a plurality of
light emitting fiber optic ports located at selected ones of the
columns and rows are transmitted to a plurality of selected light
receiving fiber optic ports located at selected remaining ones of
the rows and columns through a plurality of reflective elements
located at respective intersections formed by the selected columns
and rows in respective reflective states.
23. A free-space optical matrix crossconnect apparatus according to
claim 18, wherein the plurality of rows are oriented parallel to
each other, the plurality of columns are oriented parallel to each
other and the plurality of rows and columns are oriented
perpendicularly relative to each other.
Description
[0001] This non-provisional application claims the benefit of U.S.
Provisional Application Ser. No. 60/058,222, filed on Sep. 9,
1997.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to an optical switch device
that redirects a beam of light traveling in free-space along a
first direction to a second direction. Further, the present
invention is directed to a plurality of optical switch devices that
form a free-space optical matrix crossconnect apparatus.
[0004] 2. Description of Related Art
[0005] Modern communications companies now use fiber optic cables
as the primary carrier for voice and data signals transmitted as
light beams for ground-based communications networks. Similar to
communication networks using copper wire as the carrier for
electronic signals, fiber optic cable trunk lines are
interconnected to each other through switching nodes positioned at
various locations throughout the service area of the communications
network. Telephone calls, for example, are routed through nodes A,
B and C. Occasionally, a communications failure may take place
between nodes B and C. To restore communications, the signals which
can no longer be routed through node C must be routed through an
alternative node D. To achieve rerouting of the communications
signals, a conventional free-space micromachined optical matrix
switch is used. Also, conventional free-space micromachined optical
matrix switches are used for signal routing passes for providing
light signals to various locations.
[0006] One type of a conventional micromachined free-space optical
matrix switch 2 is introduced in FIGS. 1-4. The conventional
optical matrix switch 2 uses electrostatically actuated torsion
mirrors 4. The optical matrix switch 2 includes a first base member
6 and a second base member 8. The first base member 6 has an array
of bores 10 formed therethrough and arranged in a plurality of
columns and rows.
[0007] As best shown in FIG. 3, the torsion mirror 4 has a
reflective panel member 12 and a torsion bar 14 connected to the
reflective panel member 12 by a connector section 16. One of
ordinary skill in the art would appreciate that the reflective
panel member 12, the torsion bar 14 and the connecting section 16
are formed as a unitary construction.
[0008] Each of the bores 10 is sized to receive a respective one of
the torsion mirrors 4. Each of the torsion mirrors is mounted onto
the first base member by embedding opposite distal ends 18 and 20
of the torsion bar 14 into the first base member 6 so that each of
the torsion mirrors can pivot between a reflective state and a
non-reflective state as explained in more detail below.
[0009] The second base member 8 includes an array of cavities 22 as
best shown in FIG. 1. The first base member 6 and the second base
member 8 are connected to each other with the cavities 22 disposed
in a manner to receive an end portion of the reflective panel
member 12 when the reflective panel member 12 is in the reflective
state as shown by the torsion mirror 4 drawn in phantom in FIG. 4.
A support wall 24 retains the reflective panel member 12 at an
appropriate position for redirecting a beam of light L.sub.1 and
L.sub.2 traveling in a first direction to a second direction.
[0010] As best shown by FIG. 1, the bores 10 and the associated
torsion mirrors 4 are arranged in columns and rows labeled C1 and
C2 and R1 and R2 respectively. Each of the bores 10 are sized to
receive a respective one of the torsion mirrors 4. Electrical leads
28a-d provide electrical power to the respective ones of the
torsion mirrors 4 at the torsion bar 14. In the non-reflective
state, the reflective panel member 12 of the torsion mirror 4 is
substantially disposed in a plane formed by a first base surface 30
of the first base member 6. The reflective panel members 12 located
in R1, C1 and R2, C2 are shown in the non-reflective state whereby
the light beams L.sub.1 and L.sub.2 pass underneath the torsion
mirrors 4 as best shown by FIGS. 1, 2 and 4. In the reflective
state, the reflective panel member 12 drawn phantomly in FIG. 4 is
illustrated with an end portion of the reflective panel member 12
contacting the support wall 24. Also, the reflective panel members
are positioned within the bores so that, for example, the light
beams L.sub.1 and L.sub.2 being projected from the fiber optic
cables 26a and b positioned in rows R1 and R2 are deflected by the
reflective panel members located in R1, C2 and R2, C1 respectively
so that the light beams L.sub.1 and L.sub.2 can be redirected to
the fiber optic cables 26C and D located in C1 and C2 respectively.
In brief, because each of the light beams in this example is
redirected 90 degrees, a longitudinal axis "1" of the reflective
panel member 12, as shown in FIGS. 2 and 3, must be oriented at a
45 degree angle a relative to the incoming and outgoing light beams
L.sub.1 and L.sub.2 as best shown in FIG. 2.
[0011] For a more detailed explanation of the conventional optical
matrix switch 2 described above, reference is made to Journal of
Microelectromechanical Systems, Vol. 5, No. 4, December 1996 in an
article entitled "Electrostatic Micro Torsion Mirrors for an
Optical Switch Matrix" by Hiroshi Toshiyoshi and Hiroyuki Fujita.
For additional details regarding conventional optical matrix
crossconnects, reference is made to a book entitled "An
Introduction to Photonic Switching Fabrics" by H. Scott Hinton,
published in 1993 by Plenum Press in New York.
[0012] One problem with such an optical matrix switch described
above is that a voltage must be continuously applied to retain the
reflective panel mirror in the reflective state. Often, in
practice, the torsion mirror may not be used for years before it is
activated. Thereafter, it may continue to be used in the opposite
state for another period of years. Thus, electrical power is being
consumed while the torsion mirror is being retained in the
reflective state. Also, another problem associated with the
conventional optical matrix switch 2 is that precision alignment is
required to connect the first base member and the second base
member together so that the support wall 24 is properly oriented to
retain the reflective panel member properly in its reflective
state.
[0013] Additionally, electrostatic torque causes the reflective
panel member to move between the reflective state and the
non-reflective state. Electrostatic torque is a complicated area of
the art and there is limited data to determine when mechanical
fatigue might be expected over the lifetime of the conventional
optical matrix switch. Also, switching from the non-reflective
state to the reflective state requires approximately 300
milliseconds.
SUMMARY OF THE INVENTION
[0014] An optical switch device of the present invention is
operative to redirect the beam of light traveling in free-space
along a first direction to a second direction that is different
from the first direction. The optical switch device includes a base
member, a reflective panel and an actuator. The reflective panel is
pivotally connected to the base member and is unbiasedly movable
between a reflective state and a non-reflective state. In the
reflective state, the reflective panel is disposed in a manner to
redirect the beam of light from the first direction to the second
direction. In the non-reflective state, the reflective panel is
disposed away from the beam of light to permit the beam of light to
travel along the first direction. The actuator is connected to the
base member and the reflective panel and causes the reflective
panel to move to and between the reflective state and the
non-reflective state.
[0015] The reflective panel includes at least one hinge pin member
and at least two hinge pin connecting members. The two hinge pin
connecting members ire disposed apart from one another and are
connected to an edge portion of the reflective panel. The at least
two hinge pin connecting members project outwardly from the edge
portion of the reflective panel so that the at least one hinge pin
can be mounted to and secured between the at least two hinge pin
connecting members. A staple element having a channel sized to
receive the at least one hinge pin member is connected to the base
member with the at least one hinge pin member disposed within the
channel so that the reflective panel can pivotally move about a
pivot axis that extends through the at least one hinge pin member.
Although the staple element and the at least one hinge pin member
are disposed in close proximity to each other, the size of the
channel of the staple element permits the reflective panel to
freely pivot about the pivot axis without interference from the
staple element.
[0016] The actuator includes a hinge assembly and a translation
plate. The hinge assembly has at least one connecting rod with a
first end pivotally connected to the reflective panel and an
opposite second end pivotally connected to the translation plate.
The translation plate is slidably connected to the base member and
moves between a first position and a second position. When the
translation plate is in the first position, the reflective panel is
in the reflective state. When the translation plate is in the
second position, the reflective panel is in the non-reflective
state.
[0017] Preferably, the actuator is a scratch drive actuator
mechanism or a comb drive mechanism. At least one of these
mechanisms is connected to the translation plate and is operative
in conjunction with the base member to cause the translation plate
to move to and between the first and second positions.
[0018] Additionally, a spring element could also be used as an
actuator component. The spring element is connected to and between
the base member and the translation plate. While either the scratch
drive actuator mechanism or the comb drive mechanism moves the
translation plate to one of the first and second positions, the
spring element is operative to cause the translation plate to move
to the remaining one of the first and second positions. An
alternative actuator includes a translation plate having at least a
first channel and a second channel. A first driving pin is sized
for slidable engagement with the first channel and a second driving
pin is sized for slidable engagement with the second channel. The
first driving pin slidably engages the first channel with the
second driving pin retracts from the second channel so that the
translation plate moves to the first position with the second
driving pin being positioned offset relative to the second channel.
Correspondingly, the second driving pin slidably engages the second
channel while the first driving pin retracts from the first channel
so that the translation plate moves to the second position with the
first driving pin being positioned offset relative to the first
channel.
[0019] Another embodiment of the present invention is a free-space
optical matrix crossconnect apparatus that includes a base member,
an array of optical switch devices and a plurality of fiber optic
cables. The array of optical switch devices are operatively
connected to the base member and are arranged in a plurality of
columns and rows. Each fiber optic cable is disposed along a
periphery of the base member at a respective one of the columns and
rows and is capable of emitting and receiving a light beam.
[0020] The optical switch device of the present invention is used
in optical communications networks in order to redirect a beam of
light from an original destination node to an alternate destination
node. A plurality of optical switch devices are arranged in an
array to form a free-space optical matrix crossconnect apparatus.
The optical matrix crossconnect apparatus permits a plurality of
light beams to be redirected from respective ones of the original
destination nodes to a plurality of alternate destination
nodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention is described in detail with reference to the
following figures wherein like numerals reference like elements,
and wherein:
[0022] FIG. 1 is a partially exploded perspective view of a
conventional optical matrix switch that uses
electrostatically-operated torsion mirrors;
[0023] FIG. 2 is a top view of the conventional optical matrix
switch shown in FIG. 1;
[0024] FIG. 3 is a perspective view of the
electrostatically-operated torsion mirror used in the conventional
optical matrix switch in FIGS. 1 and 2;
[0025] FIG. 4 is a side view of the electrostatically-operated
torsion mirror shown in a non-reflective state and drawn phantomly
in the reflective state;
[0026] FIG. 5 is a perspective view of an optical matrix
crossconnect apparatus of the present invention using a plurality
of optical switch devices of the present invention;
[0027] FIG. 6 is a perspective view partially broken away of the
optical switch device of the present invention;
[0028] FIG. 7 is an enlarged perspective view partially broken away
of a reflective panel of the optical switch device of the present
invention illustrating a staple element connecting a reflective
panel to a base member;
[0029] FIG. 8 is a side view partially in cross section of the
staple element and reflective panel shown in FIG. 7;
[0030] FIG. 9 is a side view of the reflective panel in a
reflective state and a non-reflective state and a translation plate
in a first position and a second position that corresponds with the
reflective state and non-reflective state of the reflective
panel;
[0031] FIG. 10 is a graph illustrating rotation angle of the
reflective panel relative to a translation distance of the
translation plate;
[0032] FIG. 11 is a graph illustrating rotation angle of the
reflective panel as a function of time wherein the reflective panel
moves from the non-reflective state to the reflective state;
[0033] FIG. 12 is a perspective view of a second exemplary
embodiment of the optical switch device of the present invention
using two opposing scratch drive actuator mechanisms;
[0034] FIG. 13 is a third exemplary embodiment of the optical
switch device of the present invention using a scratch drive
actuator mechanism and spring elements;
[0035] FIG. 14 is a fourth exemplary embodiment of the optical
switch device using a channeled translation plate in conjunction
with corresponding driving pins driven by scratch drive actuator
mechanisms;
[0036] FIGS. 15A and 15B are top views of the channeled translation
plate in the first and second positions relative to the driving
pins;
[0037] FIG. 16 is a fifth exemplary embodiment of the optical
switch device using comb drive mechanisms to move the translation
plate to and between the first and second positions;
[0038] FIG. 17 is a perspective view of the reflective panel using
a first surface to reflect one light bean and a second surface to
reflect another light beam;
[0039] FIG. 18 is a side view of the reflective panel in FIG. 17
illustrating the first and second reflective surfaces; and
[0040] FIG. 19 is a perspective view of a reflective panel
fabricated from a semi-transparent, semi-reflective material so
that a light beam could be divided into a first light beam portion
and a second light bean portion.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0041] A first embodiment of an optical switch device 100 is
generally introduced in FIGS. 5-9. A plurality of optical switch
devices 100 forms a free-space optical matrix crossconnect
apparatus 102 which is discussed in greater detail below. As best
shown in FIG. 5, the optical switch device 100 is used for
redirecting beams of light L.sub.1-L.sub.n that are traveling in
free-space through the optical matrix crossconnect apparatus 102
along a first direction indicated by arrow F to a second direction
indicated by arrow S. As illustrated in FIG. 5, the first direction
F is different from the second direction S.
[0042] In FIG. 6, the first embodiment of the optical switch device
100 of the present invention includes a base member 104, a
reflective panel 106 and an actuator 108. The base member 104, the
reflective panel 106 and the actuator 106 are fabricated from a
stiff yet resilient material such as silicon-based materials which
are commonly used for micromachining operations.
[0043] The reflective panel 106 is pivotally connected to the base
member 104 by a hinging structure 109 that is discussed in more
detail below. In general, the hinging structure 109 enables the
reflective panel 106 to move unbiasedly between a reflective state
and a non-reflective state. With reference to FIG. 5, when the
optical switch device 100 is in the reflective state, the
reflective panel 106 is interposed in a path of a light beam, for
example, L.sub.1 traveling in free-space along direction F to the
second direction S. Again, with reference to FIG. 5, when the
reflective panel 106 is in a non-reflective state, the reflective
panel 106 is disposed away from the optical path of the beam of
light. In this instance, the beams of light pass over the
reflective panels 106 that lay in an imaginary plane substantially
parallel or coincident with the base member 104.
[0044] In FIG. 6, the actuator 108 is connected to the base member
104 and to the reflective panel 106. When energized, the actuator
108 is operative to cause the reflective panel to move to and
between the reflective state and the non-reflective state. By way
of example only, the actuator 108 illustrated in FIG. 6 is a
conventional scratch drive actuator mechanism. For additional
information regarding scratch drive actuator mechanisms, refer to
Transducers '97, 1997 International Conference on Solid-State
Sensors and Actuators, Chicago, June 16-19, 1997 in an article
entitled "A Quantitative Analysis of Scratch Drive Actuation for
Integrated X/Y Motion System" by P. Langlet et al., pp. 773-776.
The actuator 108 moves linearly as shown by arrow A in an actuation
channel 110 formed in the base member 104. Retainers 112 retains
the actuator 108 within the actuation channel 1 10 while enabling
the actuator 108 to move rectilinearly which, in turn, moves the
reflective panel 106 between the reflective state and the
non-reflective state.
[0045] As best shown in FIG. 7, the reflective panel 106 includes a
hinge pin member 1 14 and two hinge pin connecting members 116 that
are disposed apart from one another and are connected to an edge
portion 118 of the reflective panel 106. One of ordinary skill in
the art would appreciate that the hinge pin member 114, the hinge
pin connecting members 116 and the reflective panel 106 are formed
as a unitary construction. FIG. 7 shows that the reflective panel
106 includes one hinge pin member 114 and two hinge pin connecting
members 116. Although not by way of limitation, the reflective
panel 106 shown in FIG. 6 illustrates, by way of example only,
three hinge pin members 114 with four hinge pin connecting members
116.
[0046] The hinge pin connecting members 116 project outwardly from
the edge portion 118 of the reflective panel 106 so that the hinge
pin member 114 can be mounted therebetween. In FIGS. 7 and 8, a
staple element 120 is connected to the base member 104 in a manner
commonly known in micromachining techniques. The staple element 120
forms a channel 122 which is sized to receive the hinge pin member
114. When the reflective panel 106 is hinged to the base member
104, the hinge pin member 114 is disposed within the channel 122 to
provide pivotal movement of the reflective panel 106 about a pivot
axis "V" that extends through the hinge pin member 114. As best
shown in FIG. 8, the hinge pin member 114 is disposed in close
proximity with the staple element 120. However, even though the
hinge pin member 114 and the staple element 120 are disposed in
close proximity to each other, the reflective panel 106 is
permitted to freely pivot about the pivot axis "V" without
interference from the staple element 120.
[0047] With reference to FIGS. 6 and 9, the actuator 108 includes a
hinge assembly 124 and a translation plate 126. The hinge assembly
124 has a pair of connecting rods 128. A first end 130 of each of
the connecting rods 128 is pivotally connected to the reflective
panel 106. As shown in FIG. 6, the reflective panel 106 includes
arm members 132 that extend outwardly from respective lateral sides
of the reflective panel 106. The first end 130 of each of the
connecting rods 128 includes a hinging channel that receives the
staple member 120 to hingably connect the first ends 130 of each of
the connecting rods 128 to the arm members 132 of the reflective
panel 106 in a manner similar to the hinging method described
above. Each of the connecting rods 128 also includes a second end
134 which is disposed opposite of the respective first end 132 and
is pivotally connected to the translation plate 126 also in a
manner similarly described above.
[0048] With the translation plate 126 slidably connected to the
base member 104, the translation plate 126 is capable of moving
rectilinearly between a first position P.sub.F and a second
position P.sub.S. In FIG. 9, the translation plate 126 is shown in
the first position P.sub.F which results in the reflective panel
106 being disposed in the reflective state. Drawn in phantom in
FIG. 9, the translation plate 126 is moved into the second position
P.sub.S resulting in the reflective panel 106 being disposed in the
non-reflective state. A skilled artisan would appreciate that the
reflective panel rotates at a rotation angle ".alpha." between 0
degrees and 90 degrees. At 0 degrees, the reflective panel 106 is
in the non-reflective state and, at 90 degrees, the reflective
panel 106 is in the reflective state.
[0049] As shown in FIG. 9, the translation plate 126 moves a
translation distance "d" between the first position P.sub.F and the
second position P.sub.F. As shown in FIG. 10, approximately 22
microns, i.e., from the second position P.sub.S to the first
position P.sub.F, is the translation distance "d" required to
rotate the reflective panel 90 degrees, i.e., from the
non-reflective state to the reflective state.
[0050] FIG. 11 illustrates an amount of time required for the
reflective panel 106 to move from the non-reflective state and the
reflective state. The graph in FIG. I 1 illustrates that 700 .mu.s
(microseconds) are required to move the reflective panel 106 from
the non-reflective state to the reflective state, i.e., 0 degrees
to 90 degrees. Based upon electrostatically-operated torsion
mirrors, this is an improvement of approximately four hundred fold
in response time.
[0051] A second exemplary embodiment of an optical switch device
200 is illustrated in FIG. 12. The second exemplary embodiment of
the optical switch device 200 is substantially similar to the first
embodiment described above. However, the second embodiment of the
optical switch device 200 includes a first scratch drive actuator
mechanism 108a and a second scratch drive actuator mechanism 108b.
The first scratch drive actuator mechanism 108a causes the
reflective panel 106 to move from the non-reflective state to the
reflective state. The second scratch drive actuator mechanism 108b
is connected to the first scratch drive actuator mechanism 108a by
connectors 202. After the reflective panel 106 is moved to the
reflective state, the second scratch drive actuator mechanism 108b
is used to pull the first scratch drive actuator mechanism 108a in
a direction which would cause the reflective panel 106 to move to
the non-reflective state.
[0052] The second exemplary embodiment of the optical switch device
200 of the present invention requires power only when the first and
second scratch drive actuator mechanisms are moving the reflective
panel. Thus, once the reflective panel 106 is in either the
reflective state or the non-reflective state, no power is required
to retain the reflective panel in that particular state.
Furthermore, scratch drive actuators can be controlled to quickly
and accurately move the reflective panel to 90.degree., i.e. in the
reflective state. The prior art torsion mirror optical switching
device requires an accurately placed support wall.
[0053] A third exemplary embodiment of an optical switch device 300
of the present invention is illustrated in FIG. 13. Again, the
third exemplary embodiment of the optical switch device 300 is
substantially similar to the first and second exemplary embodiments
of the optical switch devices described above. For the third
exemplary embodiment of the optical switch device 300 of the
present invention, the actuator includes the scratch drive actuator
mechanism as described in the first exemplary embodiment of the
optical switch device. Also, the actuator includes spring elements
302. The spring elements 302 are connected to the scratch drive
actuator mechanism so that when the scratch drive actuator
mechanism moves the reflective panel 106 to the reflective state,
the spring elements 302 induce a spring bias against the scratch
drive actuator mechanism to return it to its original position. In
other words, the scratch drive actuator mechanism is used to move
the reflective panel 106 from the non-reflective state to the
reflective state while the spring elements 302 are used to move the
reflective panel 106 from the reflective state to the
non-reflective state.
[0054] A fourth exemplary embodiment of the optical switch device
400 is illustrated in FIG. 14. Except for the actuator, the fourth
exemplary embodiment of the optical switch device 400 of the
present invention is substantially similar to the exemplary
embodiments described above.
[0055] An actuator 408 includes a translation plate 426 that has a
pair of first channels 410 and a pair of second channels 412 as
shown in FIGS. 14, 15A and 15B. The actuator 408 also includes a
first pair of driving pins 414 and a second pair of driving pins
416. The first pair of driving pins 414 are sized for slidable
engagement -with respective ones of the first channels 410 while
the second pair of driving pins 416 are sized for slidable
engagement with respective ones of the second channels 412. Each of
the driving pins 414 and 416 have a pointed head 418 that contacts
the translation plate 426 as the respective pair of pins are
inserted into the respective channels by respective ones of scratch
drive actuator mechanisms 420. One of ordinary skill in the art
would appreciate that comb drive mechanisms could be used in lieu
of the scratch drive actuator mechanisms. Because comb drive
mechanisms are well known in the industry, no further description
is deemed necessary. The first pair of driving pins 414 slidably
engage respective ones of the first channels 410 while the second
driving pins 416 retract from the respective second channels 412 so
that the translation plate 42b moves to the first position P.sub.F
thereby moving the reflective panel 106 to the reflective state.
While the translation plate 426 is in the first position P.sub.F as
shown in FIG. 15A, the second pair of driving pins 416 are
positioned offset relative to the second channels 412. To move the
reflective panel 106 from the reflective state to the
non-reflective state, the second pair of driving pins 416 slidably
engage respective ones of the second channels 412 while the first
pair of driving pins 414 retract from the respective ones of the
first channels 410. Thus, the translation plate 426 moves to the
second position P.sub.S as shown in FIG. 15B. When the translation
plate 426 is in the second position P.sub.S, the first pair of
driving pins 414 are positioned offset relative to the respective
ones of the first channels. Note that actuator 408 moves between
the first position P.sub.F and the second position P.sub.S at the
translation distance "d."
[0056] A fifth exemplary embodiment of an optical switch device 500
is illustrated in FIG. 16. Again, the fifth exemplary embodiment of
the optical switch device 500 of the present invention is similar
to the exemplary embodiments discussed above except for the
actuator. In the fifth exemplary embodiment of the optical switch
device 500 of the present invention, a plurality of comb drive
mechanisms 508 are connected to the translation plate 526 by push
rods 534. The push rods 534 are disposed obliquely relative to the
direction of rectilinear movement shown by arrow A of the
translation plate 526. Thus, corresponding pairs of the comb drive
mechanisms 508 move the translation plate 526 to and between the
first position P.sub.F and the second position P.sub.S, thereby
moving the reflective panel 106 to and between the reflective state
and non-reflective state.
[0057] A plurality of the optical switch devices described above
can be arranged in a manner to form the free-space optical matrix
crossconnect apparatus 102 as shown in FIG. 5.
[0058] The free-space optical matrix crossconnect apparatus 102
includes the base member 104, an array of optical switch devices
100 and a plurality of fiber optic cables 140. The array of optical
switch devices 100 are operatively connected to the base member 104
and are arranged in a plurality of columns C.sub.1-C.sub.n and a
plurality of rows R.sub.1-R.sub.n. As described above, each optical
switch device 100 includes a reflective panel and an actuator. The
reflective panel is pivotally connected to the base member and
moves in an unbiased manner between the reflective state and the
non-reflective state. In the reflective state, the reflective panel
is disposed perpendicularly relative to the base member as shown in
FIG. 9. In the non-reflective state, the reflective panel is
disposed in a facially opposing relationship with the base member
also as shown in FIG. 9 and drawn phantomly. As shown in FIG. 5,
the reflective panels located in C.sub.1 R.sub.1, C.sub.2 R.sub.2
and C.sub.n R.sub.n are disposed in the reflective state wherein
the light beams traveling in free-space through the optical matrix
crossconnect apparatus 102 are redirected to respective ones of the
fiber optic cables 140 located in rows R.sub.1-R.sub.n. The
reflective panels that are in the non-reflective state allow the
light beams to travel along their respective optical paths in an
uninterrupted manner.
[0059] Each fiber optic cable 140 is disposed along a periphery 105
of the base member 104 at respective ones of the columns and rows
in FIG. 5. Further, each fiber optic cable 140 is capable of
emitting and receiving a light beam. By way of example, when the
light beam from a light emitting fiber optic cable located at a
selected column is transmitted to a selected light receiving fiber
optic cable located at a selected row, the optical switch device
located at an intersection I formed by the selected column and row
is actuated by the actuator to move the reflective panel from the
non-reflective state to the reflective state in order to reflect
the light beam from the light emitting fiber optic cable to the
selected light receiving fiber optic cable. Of course, fiber optic
cable is bi-directional in that each fiber optic cable can both
emit and receive light. Therefore, in the example above, "row" can
be substituted for "column" and vice versa without departing from
the spirit of the invention.
[0060] The free-space optical matrix crossconnect apparatus 102
also includes a plurality of collimator elements 142. Each
collimator element 142 is positioned adjacent to respective ones of
each fiber optic cable 140 and between each fiber optic cable 140
and the optical switch devices 100. Although not by way of
limitation, the plurality of collimator elements 142 and the
plurality of fiber optic cables 140 are connected to the base
member 104.
[0061] It is appreciated that for proper operation of the
free-space optical matrix crossconnect apparatus 102, when the
optical switch device located at the intersection is in the
reflective state, remaining ones of the optical switch devices
located in the selected column and row are in the non-reflective
state. Also, a skilled artisan would comprehend that a plurality of
light beams emitted from a plurality of light emitting fiber optic
cables located either at the columns or rows can be transmitted to
a plurality of selected light receiving fiber optic cables located
at selected remaining ones of the columns and rows through a
plurality of optical switch devices located at respective
intersections with the reflective panels being in the reflective
states. Although not by way of limitation, the plurality of rows
are oriented parallel to each other while the plurality of columns
are also oriented parallel to each other. As a result, the
plurality of rows and columns are oriented perpendicularly relative
to each other.
[0062] All of the exemplary embodiments of the optical switch
devices described above as well as the free-space optical matrix
crossconnect apparatus described above use a reflective panel
having only a first surface being reflective. However, one of
ordinary skill in the art would appreciate that the reflective
panel may have two reflective surfaces or is fabricated from a
material being partially reflective and partially transparent. In
the FIGS. 17 and 18, the reflective panel 106 includes a first
surface 146 and a second surface 148 which is disposed opposite the
first surface. As illustrated in FIG. 17, both the first surface
146 and the second surface 148 are fabricated from a reflective
material.
[0063] In FIG. 19, the reflective panel 106 is fabricated from a
material that is partially reflective and partially transparent.
Thus, when the reflective panel 106 is disposed in the reflective
state, a light beam L traveling in direction F is divided into a
first portion of the light beam L.sub.fp which is redirected to the
second direction S while a remaining portion of the light beam
L.sub.rp passes through the reflective panel 106 and continues in
the first direction F.
[0064] The optical switch device of the present invention as well
as the free-space optical matrix crossconnect apparatus provide
advantages over the conventional torsion mirror devices. Unlike the
torsion mirror devices, power is not required to maintain the
reflective panel in either the reflective state or non-reflective
state. Also, the scratch drive actuator mechanisms and the comb
drive mechanisms can accurately move the reflective panel into the
reflective state. Thus, there is no need for a support wall to
properly retain the reflective panel in its reflective state.
Furthermore, a consideration of mechanical fatigue as a result of
electrostatic torque is now eliminated. Additionally, switching the
reflective panel from the non-reflective state to the reflective
state is approximately four hundred times faster compared with the
torsion mirror devices.
[0065] Although the present invention has been described in
connection with specific exemplary embodiments, it should be
appreciated that modifications or changes may be made to the
embodiments of the present invention without departing from the
inventive concepts contained herein.
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