U.S. patent application number 11/202540 was filed with the patent office on 2005-12-22 for coupling device for coupling light between a planar optical component and an optical assembly.
This patent application is currently assigned to Infineon Technologies AG. Invention is credited to Kropp, Jorg-Reinhard.
Application Number | 20050281507 11/202540 |
Document ID | / |
Family ID | 31197294 |
Filed Date | 2005-12-22 |
United States Patent
Application |
20050281507 |
Kind Code |
A1 |
Kropp, Jorg-Reinhard |
December 22, 2005 |
Coupling device for coupling light between a planar optical
component and an optical assembly
Abstract
A multilayer planar optical component has a multiplicity of
optical conductors. Each optical conductor is assigned a deflecting
device that launches or couples out light at an angle to a
longitudinal direction of the respective optical conductor, and the
deflecting devices form a two-dimensional grid in the projection
onto a plane parallel to the surface of the planar optical
component. A coupling device for coupling light between such a
planar optical component and an optical assembly has a lens array
with a multiplicity of lenses disposed along a two-dimensional
grid.
Inventors: |
Kropp, Jorg-Reinhard;
(Berlin, DE) |
Correspondence
Address: |
LERNER AND GREENBERG, PA
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Assignee: |
Infineon Technologies AG
|
Family ID: |
31197294 |
Appl. No.: |
11/202540 |
Filed: |
August 12, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11202540 |
Aug 12, 2005 |
|
|
|
10277124 |
Oct 21, 2002 |
|
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Current U.S.
Class: |
385/31 ;
385/33 |
Current CPC
Class: |
G02B 6/4249 20130101;
G02B 6/43 20130101; H05K 1/0274 20130101; G02B 6/4214 20130101;
Y10S 385/901 20130101; G02B 6/30 20130101 |
Class at
Publication: |
385/031 ;
385/033 |
International
Class: |
G02B 006/26 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 2002 |
DE |
102 38 741.9 |
Claims
I claim:
1. A coupling device for coupling light between a planar optical
component and an optical assembly having a multiplicity of optical
coupling faces that form a two-dimensional grid, the planar optical
component containing a surface, deflecting faces disposed in a
two-dimensional grid in a projection onto a plane parallel to the
surface, and a multiplicity of optical conductors having
light-guiding core regions running in at least two layers disposed
parallel to one another, each of the optical conductors associated
with one of the deflecting faces, the deflecting faces launching or
coupling out the light at an angle to a longitudinal direction of
the optical conductors, the coupling device comprising: a lens
array having a multiplicity of lenses disposed along a
two-dimensional grid, said lenses of said lens array in each case
coupling the light between one of the deflecting faces for one of
the optical conductors of the planar optical component and one of
the optical coupling faces of the optical assembly.
2. The coupling device as claimed in claim 1, wherein said lens
array is constructed such that there is implemented a different
projection of the light onto a respectively assigned one of the
optical coupling faces, which equalizes different spacings of the
deflecting faces of individual ones of the layers of the planar
optical component from the surface of the planar optical
component.
3. The coupling device according to claim 1, wherein said
individual ones of said lenses have equivalent projecting
behaviors, an optical projection of an end face of a coupled
optical assembly being positioned approximately at a mean depth of
the layers.
4. The coupling device according to claim 1, wherein said lenses
are disposed in rows, said lenses in each of said rows assigned to
a specific one of the layers have a focal position adapted to a
spacing of a respective layer from the surface of the planar
optical component.
5. The coupling device according to claim 1, wherein said lenses
are disposed in rows, said lenses in each of said of rows assigned
to a specific one of the layers have, by comparison with said
lenses of other rows, a different spacing from the surface of the
planar optical component such that a beam path from said lenses is
parallel in each case.
6. The coupling device according to claim 5, wherein said lenses
are disposed in rows, said lenses of each of said rows have a
different lens thickness by comparison with said lenses of other
rows in such a way that equal scale ratios are obtained for all the
layers.
7. The coupling device according to claim 1, wherein said lens
array has a first aligning device that lines up with a second
aligning device of the planar optical component.
8. The coupling device according to claim 7, wherein said lens
array has two bores formed therein that line up with bores of the
planar optical component, and said lens array and the planar
optical component can be aligned with one another via guide pins
inserted into the bores.
9. The coupling device according to claim 1, further comprising a
plug receptacle, and said lens array is mounted in said plug
receptacle.
10. The coupling device according to claim 9, wherein plug
receptacle forms latching elements for latching an optical
plug.
11. The coupling device according to claim 1, wherein said lens
array can be connected permanently to the planar optical component
by one of soldering, bonding and latching elements.
12. A configuration, including: a planar optical component
containing: a surface; a multiplicity of optical conductors having
light-guiding core regions running in at least two layers disposed
parallel to one another; and deflecting faces disposed in a
two-dimensional grid in a projection onto a plane parallel to said
surface, each of said optical conductors associated with one of
said deflecting faces, said deflecting faces launching or coupling
out light at an angle to a longitudinal direction of said optical
conductors; and a coupling device containing a lens array having a
multiplicity of lenses disposed along a two-dimensional grid, said
coupling device connected to said planar optical component such
that in each case one of said deflecting faces of said planar
optical component being assigned to one of said lenses of said lens
array of said coupling device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional application of application Ser. No.
10/277,124, filed Oct. 21, 2002, which claims the priority, under
35 U.S.C. .sctn.119, of German patent application No. 102 38 741.9,
filed Aug. 19, 2002.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a coupling device for coupling
light between a planar optical component having a multiplicity of
optical conductors whose light-guiding core regions run in at least
two layers disposed parallel to one another, and an optical
assembly, as well as a configuration having such a planar optical
component and such a coupling device.
[0004] Optical parallel connections (parallel optical interconnects
(POIs)) are used, in particular, for high-speed connections in
local networks such as local area networks (LANs)) and system
networks such as system area networks (SANs)). A known system is
marketed by Infineon Technologies AG under the designation
trademark PAROLI. A transmitter module with a VCSEL transmitter
row, and a receiver module with a photodiode receiver row are
connected to one another in this case via fiber ribbons.
[0005] The connection of individual printed circuit boards of a
rack cabinet is usually performed via the backplane of the rack
cabinet. It is known to use optical parallel connections in order
to avoid or reduce complicated electrical wiring. In this case,
plug bushings in the backplane are used in each case to make
contact with optical modules that are mounted on the printed
circuit boards. The backplane wiring is then performed with the aid
of individual optical waveguide cables. A problem consists in the
volume of data, which is limited technically in mechanical terms by
the prescribed area of the backplane.
[0006] In view of the continuously rising volumes of data, there is
a need for structures that can be used in parallel optical
interconnects, and in particular for connecting printed circuit
boards, which take account of an increased demand on transmission
bandwidth.
SUMMARY OF THE INVENTION
[0007] It is accordingly an object of the invention to provide a
planar optical component, and a coupling device for coupling light
between a planar optical component and an optical assembly that
overcomes the above-mentioned disadvantages of the prior art
devices of this general type, which permit high-volume data
transmission in parallel optical interconnects and, for this
purpose, provide a high measure of parallelism.
[0008] With the foregoing and other objects in view there is
provided, in accordance with the invention, a planar optical
component. The planar optical component contains a surface, a
multiplicity of optical conductors having light-guiding core
regions running in at least two layers disposed parallel to one
another, and deflecting devices disposed in a two-dimensional grid
in a projection onto a plane parallel to the surface. Each of the
optical conductors is associated with one of the deflecting
devices. The deflecting devices launch or couple out light at an
angle to a longitudinal direction of the optical conductors.
[0009] In accordance therewith, the planar optical component
according to the invention is distinguished in that a multiplicity
of optical conductors run in at least two layers disposed parallel
to one another. Each optical conductor is assigned a deflecting
device that launches or couples out light at an angle to the
longitudinal direction of the respective optical conductor. The
deflecting devices form a two-dimensional grid in the projection
onto a plane parallel to the surface of the planar optical
component.
[0010] A planar optical component is thereby provided that is of
multilayer construction and in this case has structures that permit
coupling of the optical conductors of the planar optical component
to the optical conductors of a two-dimensional optical array plug.
This provides a higher measure of parallelism and permits a high
transmission rate.
[0011] The planar optical component is, in particular, a multilayer
optical printed circuit board that is used, for example, as a
backplane in a rack cabinet.
[0012] In a preferred refinement, the deflecting devices assigned
to an optical layer are disposed along a straight line. The
deflecting devices of different layers of the optical component are
preferably disposed offset from one another. This produces in the
projection onto the surface of the planar optical component a
two-dimensional grid with a high density of data lines.
[0013] The deflecting devices each preferably have reflection
regions that reflect the light guided in the optical conductors in
the direction of the surface of the planar optical component. The
reflection region of the deflecting devices is preferably disposed
here in each case at an angle of substantially 45.degree. to the
longitudinal direction of the respective optical conductor, such
that the light is substantially launched or coupled out at a right
angle to the surface of the planar component.
[0014] The deflecting devices are preferably formed by separate
mirrors embedded in the respective layer. The light launched or
coupled out by a deflecting device in this case transilluminates
the respectively higher layers.
[0015] Alternatively, it is provided that the planar structure has
cutouts on its surface in such a way that the light respectively
coupled out by the deflecting devices traverses a free beam region
up to the surface of the component. This avoids damping of the
launched or coupled-out light in the layers situated
there-above.
[0016] In a further refinement, it is provided that the deflecting
devices are formed by a wedge-shaped cutout introduced into the
component, which cutout has a silvered boundary surface running at
an angle of substantially 45.degree. to the longitudinal direction
of the optical conductors. The light reflected at the boundary
surface transilluminates the layers situated there-above in each
case. The cutout is formed, for example, by milling, etching or
laser ablation of the component.
[0017] It is likewise within the scope of the invention that the
deflecting devices are constructed in a separate component that is
inserted into a cutout in the planar optical component, or adjoins
an edge region of the planar optical component. The component is,
by way of example, a mirror disposed at an angle of 45.degree. that
is disposed in a rectangular cutout in the component or adjoins the
component. The light of the individual optical conductors in this
case transilluminates a free beam region before impinging on the
respective deflecting device. A simplified production of the
deflecting devices is advantageously not a function of the planar
optical component.
[0018] The planar optical component preferably has aligning devices
for passive alignment of the optical component. These are, for
example, bores in the optical component that serve to hold guide
pins. The deflecting devices of each optical layer are preferably
aligned with the aligning devices. As a result of this, the
position of each deflecting device is accurately defined and
adjusted both with reference to the position of the other
deflecting device and with reference to a plug to be coupled that
is positioned via the aligning device with reference to the planar
optical component.
[0019] It is preferably provided that the individual optical layers
of the planar optical component are produced separately in each
case and then connected to one another. Thus, multilayer optical
components with a multiplicity of layers can be produced in a
simple way. The individual optical layers are formed of, for
example, of plastic or glass.
[0020] A coupling device according to the invention serves to
couple light between the planar optical component as described
above and an optical assembly that has a multiplicity of coupling
faces that form a two-dimensional grid. The coupling device has a
lens array with a multiplicity of lenses disposed along a
two-dimensional grid, the lenses of the lens array in each case
coupling light between a deflecting device of an optical conductor
of an assigned planar optical component and a coupling face of an
assigned optical assembly.
[0021] The assigned optical assembly is preferably an optical plug
that has a multiplicity of optical conductors. The optical coupling
faces are in this case the optical conductor coupling faces, which
form a two-dimensional grid. Basically, however, the optical
assembly can also be, for example, an optoelectronic transmit or
receive transducer with transmit or receive elements that are
disposed in a two-dimensional grid, a transmit or receive element
in each case forming a coupling face within the meaning of the
invention.
[0022] The coupling device according to the invention permits, in
particular, the coupling of a two-dimensional optical array plug to
a multilayer planar optical component, a parallelism of the data
transmission in accordance with the invention resulting in two
dimensions.
[0023] The lens array is preferably constructed in such a way that
there is implemented a different projection of the light onto the
respectively assigned coupling face. As a result, the different
spacing of the deflecting devices of the individual optical layers
of the assigned planar optical component from the surface thereof
is equalized. Several alternatives are provided for this
purpose.
[0024] In a first alternative, the individual lenses of the lens
array have the same projecting behavior, the optical projection of
the end face of a coupled component, in particular optical plug,
being positioned approximately at the mean depth of the optical
layers. This configuration is particularly simple. The optical
launching into the uppermost and lowermost layers of the planar
optical component is, however, somewhat poorer than in the case of
the middle layers, because of the expansion of the beam path.
[0025] In a second alternative, the lenses of each row of the lens
array that are assigned to a specific optical layer have a focal
position adapted to the spacing of the optical layer from the
surface of the planar optical component. A precise projection is
therefore performed between the deflecting device and the assigned
coupling face. It is true that the magnification in the optical
projection differs for each layer. However, this is of subordinate
importance as long as the optical coupling suffices.
[0026] In a third alternative, the lenses of each row of the lens
array that are assigned to a specific optical layer have, by
comparison with the lenses of other rows, a different spacing from
the surface of the assigned planar optical component in such a way
that the beam path in the lens bodies is parallel in each case. The
lenses can all have the same refractive power in this case. The
nearer an optical layer is to the surface of the planar optical
structure, the greater will be the spacing of the associated lenses
of the lens array from the surface. Moreover, the lenses of each
row of the lens array have preferably a different lens thickness by
comparison with the lenses of other rows in such a way that equal
scale ratios are obtained for all the layers.
[0027] The lens array preferably has an aligning device that lines
up with the aligning device of the assigned planar optical
component. For this purpose, there are provided, for example, two
bores in the body of the lens array that line up with the
corresponding bores of the assigned planar optical component. The
lens array and the planar optical component can be aligned with one
another via guide pins inserted into the respective bores.
[0028] The lens array is preferably mounted in a plug receptacle
for holding a two-dimensional optical plug. Moreover, the plug
receptacle preferably forms latching elements for latching such an
optical plug.
[0029] The lens array can preferably be connected permanently to
the assigned optical component by soldering, bonding or by use of
latching elements, for example. The lens array, the plug receptacle
and the guide pins can in this case form a structural unit that is
connected to the planar optical component.
[0030] Finally, the invention also relates to a configuration
having the planar optical component and the coupling device, in
which the coupling device is connected to the planar optical
component in such a way that in each case a deflecting device of
the planar optical component is assigned to a lens of the lens
array of the coupling device. This is performed, for example, via
the aligning device mentioned. The specific refinement of a
multilayer planar optical component in conjunction with a
two-dimensional lens array permits a two-dimensional optical plug
to be coupled to a multilayer planar optical component, light
preferably being launched or coupled out at a right angle to the
surface of the planar optical component. The configuration is
particularly suitable for coupling a two-dimensional optical plug
to a multilayer optical backplane of a rack cabinet.
[0031] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0032] Although the invention is illustrated and described herein
as embodied in a coupling device for coupling light between a
planar optical component and the optical assembly, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein
without departing from the spirit of the invention and within the
scope and range of equivalents of the claims.
[0033] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a diagrammatic, plan view of a multilayer optical
printed circuit board with a two-dimensional array of deflecting
mirrors according to the invention;
[0035] FIG. 2 is a sectional view of the multilayer optical printed
circuit board with a multiplicity of deflecting mirrors;
[0036] FIG. 3 is a sectional view of the multilayer optical printed
circuit board with the multiplicity of deflecting mirrors, a free
beam region being formed over each deflecting mirror;
[0037] FIG. 4 is a sectional view of the multilayer optical printed
circuit board with a wedge-shaped cutout that forms a reflecting
layer;
[0038] FIG. 5A is a plan view of a lens array;
[0039] FIG. 5B is a sectional view of the lens array;
[0040] FIG. 6 is a sectional view of a first configuration having
the multilayer optical printed circuit board, the lens array and an
optical plug;
[0041] FIG. 7 is a sectional view of a second configuration having
the multilayer optical printed circuit board, the lens array and
the optical plug;
[0042] FIG. 8 is a sectional view of a third configuration having
the multilayer optical printed circuit board, the lens array and
the optical plug;
[0043] FIG. 9 is a sectional view of a plug unit with the
multilayer optical printed circuit board, the lens array and a plug
receptacle; and
[0044] FIG. 10 is a sectional view of the multilayer optical
printed circuit board having a cutout in which an obliquely running
mirror is disposed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] Referring now to the figures of the drawing in detail and
first, particularly, to FIG. 1 thereof, there is shown a plan view
of a multilayer optical printed circuit board 1 having an
multiplicity of optical conductors (wave-guides) 2 at whose ends a
reflecting deflecting mirror 3 is disposed in each case. The
wave-guides 2 run in different parallel planes or optical layers of
the printed circuit board 1. A plurality of the waveguides 2 are
located in this case in each optical layer. Wave-guide ends or the
deflecting mirrors 3 assigned to the latter are disposed offset
from one another from layer to layer such that the deflecting
mirrors 3 form in the projection onto the surface of the planar
optical component 1 a two-dimensional grid 4 that has 4.times.8
grid points in the exemplary embodiment illustrated.
[0046] As illustrated in FIG. 1, the grid is preferably such that
the spacing between the grid points in both spatial directions of
the grid is the same. However, the spacings can basically also
differ from one another.
[0047] Two bores 51, 52 are disposed in the printed circuit board 1
in a symmetrical configuration relative to the grid 4 of the
deflecting mirrors 3. The bores 51, 52 share the purpose, first, of
aligning the printed circuit board 1 with reference to further
components, and, second, of aligning the individual planes relative
to one another. Thus, the individual planes of the printed circuit
board 1 are produced in such a way that the waveguide ends or the
deflecting mirrors 3 disposed on the latter have a defined
alignment in each plane with reference to the bores 51, 52.
[0048] The multilayer optical printed circuit board 1 forms, for
example, a backplane of a circuit housing. Further printed circuit
boards of the circuit housing are respectively connected via a
two-dimensional array plug to the backplane such that backplane
cabling is eliminated. However, in principle, the printed circuit
board can be used in any desired context in which data are to be
transmitted with high parallelism, and there is to be a coupling
between a multilayer planar optical component and an array plug
and/or an optoelectronic module. It can also be provided, in
particular in this case, that optoelectronic modules and further
electric components are disposed on the printed circuit board. The
optoelectronic modules launch light into the individual optical
conductors 2, or decouple it from the latter.
[0049] The production of the planar optical component having the
multiplicity of waveguides 2 in different layers can be performed
in a plurality of ways. In the case of the use of multimode
waveguides, production can be performed using the particularly
simple plastic technology. In this case, a first layer of flat
plastic is structured, for example, by hot embossing with the
light-guiding core regions provided in this layer, together with
the associated reflection surfaces or deflecting mirrors 3. The
reflection surfaces are provided for this purpose with a
corresponding silvering. It is perfectly possible for the silvering
to be wavelength-selective in this case. Subsequently, the plastic
material with the higher refractive index is knife-coated into the
embossed trenches. A multilayer optical printed circuit board is
produced by disposing a plurality of layers produced in this way
one above another.
[0050] However, other methods of production are also conceivable.
For example, the individual layers can be formed of thin glass
layers with a thickness of 100 .mu.m, for example, such as are
commercially available. The individual waveguides can be introduced
by etching and subsequent casting of a core material or else by
diffusion and ion exchange.
[0051] FIG. 2 shows a first example for the implementation of a
planar optical component in accordance with FIG. 1, in a lateral
sectional view. The section is in this case taken along the line
II-II shown in FIG. 1, and therefore positioned such that a
plurality of waveguides 2 are also sectioned. In the exemplary
embodiment illustrated, four waveguide planes or layers 1a, 1b, 1c,
1d are disposed one above another on a substrate 6. Each layer 1a,
1b, 1c, 1d has a plurality of optical conductors in the form of
strip waveguides. In the sectional illustration, an optical
conductor with a light-guiding core, 21a, 21b, 21c, 21d is to be
seen in each case. Disposed offset in each layer 1a, 1b, 1c, 1d are
the reflecting mirrors 3 that in each case couple out or--in the
case of a reverse beam path--launch light of the associated
waveguide 2 at right angles to a longitudinal direction of the
optical conductor and thus perpendicular to a surface 101 of the
planar optical component. The light respectively transilluminates
the layers situated above in this case. The mirrors 3 are
constructed in each case as separate elements.
[0052] FIG. 3 shows an alternatively constructed optical printed
circuit board 1' with reflecting surfaces 3. Provided in accordance
therewith in the optical printed circuit board 1' is a cutout 7
that is formed by virtue of the fact that there are formed in the
individual waveguide planes 1a', 1b', 1c', 1d' cutouts that adjoin
the respective reflecting mirrors 3. The individual layers 1a',
1b', 1c', 1d' are offset in this case in such a way that in each
case no waveguide material is located over the individual mirrors 3
of the individual layers. The light coupled out or launched is
therefore not damped by layers situated above. The free beam region
provided by the cutout 7 can, if desired, also be filled by an
optically transparent material.
[0053] In the exemplary embodiment of FIG. 4, the reflecting
mirrors are provided by a wedge-shaped cutout 8 that converges in
the direction of a surface 101" of an optical printed circuit board
1", and forms in the printed circuit board 1" a silvered coupling
face 81 running at an angle of substantially 45.degree.. The cutout
8 is constructed, for example, by milling, laser ablation or
etching. The coupling face 81 running at an angle of 45.degree. is
silvered from behind after introduction into the printed circuit
board material, such that it provides a multiplicity of reflecting
mirrors for the individual optical conductor core regions 21a",
21b", 21c", 21d".
[0054] A further exemplary embodiment is shown in FIG. 10.
According thereto, there is provided in a printed circuit board
1'", a cutout 9 in which a mirror 10 extends which runs at an angle
of 45.degree.. The light exits in each case from the optical
conductors 21a'", 21b'", 21c'" and 21d'", and is reflected upward
after traversing a free beam region through the mirror 10 that
provides a multiplicity of deflecting mirrors. This refinement is
particularly simple, since the deflecting mirrors need not be
integrated in the optical printed circuit board 1'". An additional
beam widening is disadvantageous because of the free beam region
after exiting of the light from the respective waveguide. The
cutout 9 can be filled with an optically transparent material.
[0055] Instead of the mirror 10, it is also possible to use another
structure with a multiplicity of individually constructed
deflecting mirrors. In this case each deflecting mirror can be
furnished with separate optical projecting properties, for example
can be of focusing construction. Each deflecting mirror can, for
example, implement a focusing effect whose strength is a function
of the layer to which the mirror is aligned and, if appropriate,
also of the length of the free beam region that the light traverses
before impinging on the mirror.
[0056] The mirror 10 or the other structure can also alternatively
be disposed to the side of the edge of the printed circuit board
1'".
[0057] FIGS. 5A and 5B shows a plan view and a section of a
two-dimensional lens array 11 with a multiplicity of lenses 111
that are disposed along a grid. In the exemplary embodiment
illustrated, the grid is identical to the grid 4 of the deflecting
mirrors 3 of the optical printed circuit board of FIGS. 1 to 4.
[0058] The lens array 11 is preferably disposed between the
multilayer optical printed circuit board 1 and a two-dimensional
optical multiple plug, and couples the light between the respective
deflecting mirrors 3 of the printed circuit board 1 and individual
optical conductor coupling faces that form the optical plug in a
way known per se.
[0059] The lens array 11 has two bores 131, 132 that are of the
same size and have the same spacing as the bores 51, 52 of the
printed circuit board 1, such that the printed circuit board 1 and
the lens array 11 can be fixed and aligned with one another via
guide pins inserted into the bores 51, 52, 131, 132. When the lens
array 11 is mounted on the printed circuit board 1, the lens array
11 is automatically aligned in this case with the reflecting
surfaces 3 of the printed circuit board 1.
[0060] The deflecting mirrors 3 of the individual layers 1a, 1b,
1c, 1d of the optical printed circuit board 1 naturally have a
different spacing from the surface 101 of the component. It follows
from this that the radiation, reflected at the deflecting mirrors
3, of the individual optical conductors experience a different beam
expansion up to the coupling with the associated lens of the lens
array 11, depending on in which layer or at which depth the
waveguide is located. This can lead to problems in focusing the
light beam onto the associated coupling face of an optical
conductor of an optical plug. A plurality of alternative
configuration variants that avoid or reduce such problems are
explained below.
[0061] FIGS. 6 to 8 illustrate diagrammatically the optical printed
circuit board 1, the lens array 11 and an optical plug 12 that has
a multiplicity of optical conductors 123 in a two-dimensional array
configuration. Light is coupled in each case via the lenses 111 of
the lens array 11 between end faces 122 of the optical conductors
123 of the plug 12 and the deflecting mirrors 3 of the optical
conductors of the optical printed circuit board 1. It may be
pointed out in this case that the deflecting mirrors can also be
constructed in accordance with the refinements of FIGS. 2, 3 and
10, or in another way.
[0062] In accordance with FIG. 6, the lenses 111 of the lens array
11 are of identical construction. This advantageously permits a
particularly simple production of the lens array 11. The lenses 111
are constructed in this case in such a way that the optical
projection of the plug end face 121 of the coupled optical plug 12
is positioned approximately in the middle one of the optical layers
1a, 1b, 1c, 1d. Thus, for the light of the wave-guides of the
middle optical layers 1b, 1c an ideal projection is performed onto
the corresponding coupling faces 122 of the optical conductors 123
of the optical plug 121. Because of the expansion of the beam path,
the optical coupling between the light of the waveguides on the
upper and lower layers 1a, 1d is somewhat poorer than in the middle
layers, but still acceptable.
[0063] A configuration with an alternative refinement of a lens
array 11' is illustrated in FIG. 7. It may first be pointed out in
this case that each row 111a', 111b', 111c', 111d' of the lens
array 11' is assigned to a row of deflecting mirrors of a layer 1a,
1b, 1c, 1d' of the planar optical component 1. It is provided that
each lens row 111a', 111b', 111c', 111d' of the lens array 11' is
constructed in such a way that the focal position differs in each
case and is tuned to-the spacing of the deflecting device 3
assigned to the lenses. It is therefore to be seen that the lenses
111a' disposed on the left in FIG. 4 effect less focusing than the
lenses 111d' of the lens array that are disposed on the right.
[0064] It is disadvantageous in this configuration that the
magnification during the optical projection differs for each
optical layer 1a, 1b, 1c, 1d. However, this is of subordinate
importance as long as the optical coupling is sufficient.
[0065] FIG. 8 shows another variant in which the beam path in the
lenses of the individual rows 111a", 111b", 111c", 111d" of the
lens array 11" are configured in such a way that the beam path runs
parallel in each case in the lens body. Consequently, each row of
the lens array has a different spacing from the printed circuit
board 1 and a different lens thickness. The different spacing of
the lenses from the printed circuit board 1 ensures that despite
the equal refractive power of the lenses, the light of each layer
in the lens body is guided in parallel. The different thickness of
the lenses provides a standard spacing from the optical plug 12.
The result is an adapted height gradation of the lens surfaces to
the optical layers of the printed circuit board 1. Despite the
differences in spacing, equal scale ratios are thereby provided for
the waveguides of all the layers 1a, 1b, 1c, 1d.
[0066] It is also possible to use combinations of the embodiments,
illustrated in FIGS. 7 and 8, of the lens array, that is to say the
lenses of the individual rows have both a different focal length
and a different lens thickness.
[0067] The lenses of the lens array 11, 11", 11" are produced, for
example, from optically transparent plastics by precision casting
technology. In the case of the variants of FIGS. 6 and 7, it is
also possible to use other production methods and, for example, to
use graded-index lenses or Fresnel lenses produced by ion
exchange.
[0068] FIG. 9 shows all the essential components of a configuration
that contains the optical printed circuit board 1 and the lens
array 11. The printed circuit board 1 and the lens array 11 are
fixed to one another via guide pins 14a, 14b inserted into
respective bores, and aligned with one another in such a way that
the respective grids formed by the lenses 111 or by deflecting
mirrors are situated one above another. Since the guide pins 14a,
14b project over the lens array 11 in the direction of a plug to be
coupled, they serve additionally to center a plug to be coupled
that is provided with a fiber array. The lens array is mounted
permanently in an outer plug socket 15 or plug receptacle. The plug
socket 15 has the task of bringing forward an optical plug to be
coupled during a plugging operation. It can be configured as a
funnel as shown in FIG. 9, for example, but in a departure
therefrom, can also include mutually tuned centering stages.
Moreover, function elements 16 for latching the optical plug to be
coupled with the plug socket 15 are provided in the plug
socket.
[0069] The plug socket 15, the lens array 11 and the plug pins 14a,
14b form a permanent structural transmission unit in the exemplary
embodiment illustrated. During mounting, the unit is placed on the
multilayer optical printed circuit board 1 with the aid of the plug
pins 14a, 14b and centered in the process. The transmission unit
can be fixed on the printed circuit board 1 by bonding or else by
soldering. In the latter case, parts of the surfaces of the printed
circuit board and the transmission unit have suitable metallic
coatings. It can also be provided that the transmission unit and
the printed circuit board 1 have form-fitting elements such as
latching hooks and corresponding openings such that the
transmission unit can also be connected latchably to the printed
circuit board 1.
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